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6 pages, 4612 KiB

Open AccessProceeding Paper

Flood Detection in Complex Surface Mining Areas Using Satellite Data for Sustainable Management

by Konstantinos Karalidis, Georgios Louloudis, Christos Roumpos, Eleni Mertiri and Francis Pavloudakis

Mater. Proc. 2023, 15(1), 1; https://doi.org/10.3390/materproc2023015001 - 09 Oct 2023

Viewed by 608

Abstract

In the context of the lignite phase-out plan in Greece, the aim of the Public Power Corporation (PPC) is sustainable mine closure and land reclamation and, at the same time, the enhancement of safe mining and post-mining activities. The main objective of this [...] Read more.

In the context of the lignite phase-out plan in Greece, the aim of the Public Power Corporation (PPC) is sustainable mine closure and land reclamation and, at the same time, the enhancement of safe mining and post-mining activities. The main objective of this study is to provide a methodology to identify the areas in complex surface mining landscapes that are more vulnerable to flooding using remotely sensed satellite data. This is an integral part of the strategic planning of the new land uses and the design of new and improved water management strategies. In this research, the change detection method is applied using Synthetic Aperture Radar (SAR), and flood-prone zones are delineated. Full article

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6 pages, 3817 KiB

Open AccessProceeding Paper

The Hydrogeological Conditions as a Crucial Factor for Creating Pit Lakes: The Case of Kyparissia Mine in Megalopolis, Greece

by Georgios Louloudis, Christos Roumpos, Eleni Mertiri, Georgios Kasfikis and Eleni Vasileiou

Mater. Proc. 2023, 15(1), 2; https://doi.org/10.3390/materproc2023015002 - 09 Oct 2023

Viewed by 730

Abstract

Hydrogeological conditions constitute a crucial factor during mining excavations. However, they could also define when and how rapidly the final pit voids will be filled with water after mine closure. They also influence the final steady-state water volume of the lake formed. This [...] Read more.

Hydrogeological conditions constitute a crucial factor during mining excavations. However, they could also define when and how rapidly the final pit voids will be filled with water after mine closure. They also influence the final steady-state water volume of the lake formed. This paper investigates the hydrogeological conditions of the Kyparissia surface mine in the Megalopolis lignite field. Due to the very rapid filling from three karstic aquifers, these were the determining factors for ceasing exploitation in 2012. A pit lake has been formed in the mine void since 2017, with an average depth of 30 m and a maximum depth of approximately 36 m, extending to a surface of 0.8 km². The significant role of the hydrogeological setting is highlighted in the creation, maintenance, and development of pit lakes. Full article

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8 pages, 219 KiB

Open AccessProceeding Paper

Understanding the Social License to Operate from a Cultural Perspective: The Case Studies of Australia, Greece, and India

by Chrysanthi Rodolaki and George Barakos

Mater. Proc. 2023, 15(1), 3; https://doi.org/10.3390/materproc2023015003 - 09 Oct 2023

Viewed by 983

Abstract

A reliable, sustainable, and transparent supply of critical raw materials is vital for developing future technologies and transitioning to a carbon emission-free world. However, mining can generate social, economic, and environmental impacts, compromising the sector’s public perception and jeopardising the social acceptance of [...] Read more.

A reliable, sustainable, and transparent supply of critical raw materials is vital for developing future technologies and transitioning to a carbon emission-free world. However, mining can generate social, economic, and environmental impacts, compromising the sector’s public perception and jeopardising the social acceptance of operations. In various contexts, the social impacts of mining are assessed with different sets of indexes and targets. This study investigates cultural indicators of societal acceptance for mining critical raw materials in Australia, Greece, and India. Identifying and comparing the perception of mining in the three countries points out the difference in each society’s behaviour based on their culture. Full article

6 pages, 4785 KiB

Open AccessProceeding Paper

A Scenario-Based Analysis for the Selection of Post-Mining Land Uses Applying a Cellular Automata Model

by Konstantinos Karalidis, Christos Roumpos, Aikaterini Servou, Nikolaos Paraskevis and Francis Pavloudakis

Mater. Proc. 2023, 15(1), 4; https://doi.org/10.3390/materproc2023015004 - 09 Oct 2023

Viewed by 384

Abstract

In line with the European Green Deal, Greece plans to achieve climate neutrality by 2050. In this context, the country aims to cease all lignite mines by 2028 and transition away from coal. Effective strategic planning is crucial for mine closure, considering technical, [...] Read more.

In line with the European Green Deal, Greece plans to achieve climate neutrality by 2050. In this context, the country aims to cease all lignite mines by 2028 and transition away from coal. Effective strategic planning is crucial for mine closure, considering technical, environmental, and social factors. Cellular automata models, known for their adaptability to dynamic environments, are widely used for land use simulation. This research focuses on the surface mining area of Ptolemais in Western Macedonia, Greece, using a cellular automata model to predict new land uses in two scenarios: industrial and agricultural development. The interpretation of the results proved that the applied model could be a helpful tool for the planning and analysis of new land uses considering the spatiotemporal aspect of each scenario. Full article

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7 pages, 826 KiB

Open AccessProceeding Paper

Using Force Field Analysis for Examining and Managing Stakeholders’ Perceptions of Mining Projects

by Francis Pavloudakis, Philip-Mark Spanidis and Christos Roumpos

Mater. Proc. 2023, 15(1), 5; https://doi.org/10.3390/materproc2023015005 - 10 Oct 2023

Cited by 1 | Viewed by 836

Abstract

This article uses force field analysis (FFA) to examine the role of stakeholders in the lignite mining project of the Western Macedonia Region, Greece, which is entering the closure phase at an accelerated pace due to energy transition policies. The FFA is applied [...] Read more.

This article uses force field analysis (FFA) to examine the role of stakeholders in the lignite mining project of the Western Macedonia Region, Greece, which is entering the closure phase at an accelerated pace due to energy transition policies. The FFA is applied in four steps: identification of internal and external stakeholders; classification of them into groups according to their interest and influence on the project; assessment of each stakeholder’s strength in quantitative terms and graphical representation of it in a force field diagram; and management of stakeholders’ perceptions. The result of this article is the determination of a specific course of action that balances the benefits and impacts for all stakeholders. Full article

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7 pages, 5416 KiB

Open AccessProceeding Paper

Face Mapping in Open Pit Mines—A New Approach

by Agni Patra, Konstantinos Pilalidis, Francis Pavloudakis and Ioannis Kapageridis

Mater. Proc. 2023, 15(1), 6; https://doi.org/10.3390/materproc2023015006 - 11 Oct 2023

Viewed by 776

Abstract

In the South Field Mine located in the Lignite Center of Western Macedonia, Northern Greece, a method of photogrammetry was successfully used for mapping quickly and precisely the faces of all mine benches. The important information, which was not available with the conventional [...] Read more.

In the South Field Mine located in the Lignite Center of Western Macedonia, Northern Greece, a method of photogrammetry was successfully used for mapping quickly and precisely the faces of all mine benches. The important information, which was not available with the conventional way of face sampling, is knowledge of the exact position and thickness of the minable lignite seams. This allows the development of a powerful lignite deposit exploitation tool and can certainly be applied to any other surface mine. Another major advantage of using this methodology concerns the spatial accuracy of the lignite-quality data produced from the lab analysis of the face samples. This information is crucial and may be used as inputs in a database that can be integrated into drilling, survey, and other data, and improve the geological and reserve models of the exploitation area. Full article

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8 pages, 754 KiB

Open AccessProceeding Paper

Reconciliation of Conflicting Societal Objectives: Nature Protection vs. Mining

by Eberhard Falck and Vitor Correia

Mater. Proc. 2023, 15(1), 7; https://doi.org/10.3390/materproc2023015007 - 11 Oct 2023

Viewed by 424

Abstract

Critical raw materials (CRMs) like lithium, cobalt, and copper are crucial for our modern economy, driving digitalisation and the energy transition. The EU-funded CIRAN project addresses the challenge of balancing environmental protection and the demand for CRMs. It focuses on developing innovative land-use [...] Read more.

Critical raw materials (CRMs) like lithium, cobalt, and copper are crucial for our modern economy, driving digitalisation and the energy transition. The EU-funded CIRAN project addresses the challenge of balancing environmental protection and the demand for CRMs. It focuses on developing innovative land-use governance models, social contract frameworks, and business models. These initiatives enable informed and sustainable decisions in mining operations, fostering environmental protection while meeting the growing need for CRMs. Full article

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8 pages, 1072 KiB

Open AccessProceeding Paper

Curriculum Development for Improving Mineral Exploration-Related Master Programs towards Innovation, Entrepreneurship and Social Responsibility

by Sibila Borojević Šoštarić, Gabriela Paszkowska, Nils Jansson, Luis Lopes, Alberto Sanchez Miravalles, Ana Maričić and Ferenc Mádai

Mater. Proc. 2023, 15(1), 8; https://doi.org/10.3390/materproc2023015008 - 11 Oct 2023

Viewed by 518

Abstract

Nordic and West Balkan countries are major investment regions in Europe for greenfield and brownfield mineral exploration; however, the availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle is limited, especially in West Balkan countries. The partners of [...] Read more.

Nordic and West Balkan countries are major investment regions in Europe for greenfield and brownfield mineral exploration; however, the availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle is limited, especially in West Balkan countries. The partners of the TIMREX EIT RawMaterials-labeled MSc program have developed a joint curriculum focused on innovative raw materials prospecting and exploration methods, with strong innovation and entrepreneurial components. The program incorporates new exploration techniques and methodologies, portable and more highly sensitive equipment, robotized exploration equipment and the processing and interpreting of large, multidimensional datasets. The TIMREX curriculum was built around the ideal mineral exploration program, as suggested by raw materials stakeholders and orientated to field geology, exploration techniques and data processing, and also includes elements of sustainability, transversal societal and regulatory aspects. The program also focuses on EIT Overarching Learning Outcomes (OLO-s), which are embedded as core elements of the curriculum (innovation, entrepreneurship, sustainability, creativity, leadership and intercultural competencies). Significant contributions to the OLOs also arise from cross-organizational program elements, including the Exploration Entrepreneurship course, summer field camp, the Internship and the Social and Civic internship. Full article

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6 pages, 1626 KiB

Open AccessProceeding Paper

Narrow Reef Mining (NRM)—Innovative Mining Technology for Narrow, Sub-Horizontal PGE Ore Bodies

by Vječislav Bohanek, Luka Petro and Sibila Borojević Šoštarić

Mater. Proc. 2023, 15(1), 9; https://doi.org/10.3390/materproc2023015009 - 11 Oct 2023

Viewed by 801

Abstract

The expansion of mining activities around the world due to the increasing population and demand for metals are transforming mining methods. Mining is going deeper and deeper, and deposits of small thicknesses and large inclinations are becoming interesting for mining. Mining technology must [...] Read more.

The expansion of mining activities around the world due to the increasing population and demand for metals are transforming mining methods. Mining is going deeper and deeper, and deposits of small thicknesses and large inclinations are becoming interesting for mining. Mining technology must be adapted to the conditions of each deposit. The NRE fleet is a unique, innovative, electric robotic solution for underground mining, aiming to increase safety and productivity while reducing capital and operating costs. The fleet is specifically designed for mining sub-horizontal PGE orebodies, but in the future, it can be used for mining other deposits. Full article

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7 pages, 233 KiB

Open AccessProceeding Paper

Toward the Exploitation of Unconventional Heavy Oils: Electrostatic Technologies for the Minimization of Dehydration Cost

by Christina Argyropoulou, Vassilis Gaganis and Dimitris Marinakis

Mater. Proc. 2023, 15(1), 10; https://doi.org/10.3390/materproc2023015010 - 13 Oct 2023

Viewed by 543

Abstract

The growing energy demand has created a special interest in the unconventional reserves of heavy and extra-heavy oil, despite their difficulty both in extraction and separation due to the high specific gravity, high viscosity, low mobility, and high content in asphaltenes and heteroatoms. [...] Read more.

The growing energy demand has created a special interest in the unconventional reserves of heavy and extra-heavy oil, despite their difficulty both in extraction and separation due to the high specific gravity, high viscosity, low mobility, and high content in asphaltenes and heteroatoms. The study is a comprehensive review of the implemented technologies and emerging techniques for the dehydration of heavy and extra-heavy oils with an °API gravity from 20 to below of 10 and a viscosity between 100 and 10,000 cP. Special focus is given to the electrostatic treatment, due to its versatility of applications and its potential for the further improvement in dehydration efficiency, thus reducing the demand for energy and chemical demulsifiers. Full article

7 pages, 1078 KiB

Open AccessProceeding Paper

Evaluation Methodology of Open-Pit Mine Overall Slope Failure Risks

by Natalija Pavlovic, Branko Petrovic and Tomislav Subaranovic

Mater. Proc. 2023, 15(1), 11; https://doi.org/10.3390/materproc2023015011 - 16 Oct 2023

Viewed by 562

Abstract

Slope failure risks and corresponding probabilities and consequences are related to a large number of causes, thus, their quantification is a complex process. The semi-qualitative method FMEA was modified into a quantitative value method V-FMEA for specific mining requirements, which enabled the risk [...] Read more.

Slope failure risks and corresponding probabilities and consequences are related to a large number of causes, thus, their quantification is a complex process. The semi-qualitative method FMEA was modified into a quantitative value method V-FMEA for specific mining requirements, which enabled the risk assessment to perform a constant check of acceptable probabilities of the overall slope failure and the implementation of detection and preventive activities as functions of the present value of consequence costs. The large open-pit mine Field E slope failure served as a good example of the proposed new risk evaluation methodology. Full article

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6 pages, 2155 KiB

Open AccessProceeding Paper

Applying Model-Based Systems Engineering to Tailings Storage Facility Structures

by Bartłomiej Bursa, Paweł Stefaniak and Ioannis Kakogiannos

Mater. Proc. 2023, 15(1), 12; https://doi.org/10.3390/materproc2023015012 - 16 Oct 2023

Viewed by 538

Abstract

Model-based systems engineering (MBSE) is a methodology that focuses on creating and exploiting the digital system and engineering domain models as the primary means of exchange of information, feedback, and requirements, as opposed to document-centric systems engineering. The numerical model that encompasses all [...] Read more.

Model-based systems engineering (MBSE) is a methodology that focuses on creating and exploiting the digital system and engineering domain models as the primary means of exchange of information, feedback, and requirements, as opposed to document-centric systems engineering. The numerical model that encompasses all structural information lies at the heart of the system. Furthermore, this computational model can calculate crucial parameters such as displacements, stresses, and strains. The innovative SEC4TD project, funded by the EIT Raw Materials, proposes an integrated end-to-end (E2E) solution composed of three hardware and software innovative products for mining operators and service providers that will enable multi-scale multi-platform data collection and visualization, events prediction, effective information management, and data traceability. Within this framework, SEC4TD has commenced utilizing the MBSE approach to develop a system specifically for tailings dams. The system integrates all the data from the field, laboratory tests, and monitoring systems to assess the stability of the tailings dam. In the event of unsatisfactory results or the identification of potentially dangerous occurrences, the system immediately notifies the engineering personnel responsible for the tailings storage facility. The MBSE system for tailings dams has been tested at the two tailings storage facilities, one in Poland and another in Bosnia. The article describes the concept, architecture, and data used in the system. Full article

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7 pages, 2137 KiB

Open AccessProceeding Paper

Extractive Waste Management in Coal Surface Mining Projects—A Circular Economy Approach

by Ariadni Sokratidou, Christos Roumpos, Nikolaos Paraskevis, Aikaterini Servou and Francis Pavloudakis

Mater. Proc. 2023, 15(1), 13; https://doi.org/10.3390/materproc2023015013 - 16 Oct 2023

Cited by 1 | Viewed by 591

Abstract

Coal surface mines usually occupy large areas for the development of mining activities, and they affect and change the landscape and land cover in various ways. After completing the exploitation of a specific mine section, the sustainable reclamation of mining land is directly [...] Read more.

Coal surface mines usually occupy large areas for the development of mining activities, and they affect and change the landscape and land cover in various ways. After completing the exploitation of a specific mine section, the sustainable reclamation of mining land is directly associated with the optimal exploitation of waste dumping sites. This study investigates the main issues related to extractive waste management concerning the progressive development of dumping sites in continuous surface mining projects, from initial excavations to the completion of mining operations and post-mining utilization, considering basic geospatial parameters and circular economy principles. In this framework, the waste dumping areas of the exhausted Amyntaion lignite mines in North Greece are examined. Research results showed that the waste management that was applied in this area was characterized by sustainable attributes, and an equilibrium was observed in the dumping material volume. Full article

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4 pages, 1049 KiB

Open AccessProceeding Paper

Transforming Decommissioned Mines to a Gravity Energy Storage System

by Michail Galetakis, Georgios Biotakis, Vasilios Deligiorgis and Emmanouil Varouchakis

Mater. Proc. 2023, 15(1), 14; https://doi.org/10.3390/materproc2023015014 - 16 Oct 2023

Viewed by 511

Abstract

A new gravitational energy storage system is studied, which uses a reversible conveyor belt to elevate granular material and a regenerative motor for energy harvesting during the downward movement of material. This system can be installed in decommissioned open-pit mines, which offer suitable [...] Read more.

A new gravitational energy storage system is studied, which uses a reversible conveyor belt to elevate granular material and a regenerative motor for energy harvesting during the downward movement of material. This system can be installed in decommissioned open-pit mines, which offer suitable topography and available material. The parameters affecting the performance of this energy storage system are examined by employing sensitivity/uncertainty analysis. Results showed that the inclination of the conveyor, the filling factor of the conveyor belt, and the efficiency of the motor/generator had the greatest impact on the overall energy storage efficiency. Full article

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7 pages, 327 KiB

Open AccessProceeding Paper

Knowledge Gaps in Mining Operations: Empirical Evidence from the Greek Lignite Mining Industry

by Philip-Mark Spanidis, Francis Pavloudakis and Christos Roumpos

Mater. Proc. 2023, 15(1), 15; https://doi.org/10.3390/materproc2023015015 - 16 Oct 2023

Cited by 1 | Viewed by 492

Abstract

The objective of the paper is an introductory discussion on the knowledge gaps (KGs) observed in mining operations. A qualitative research (QLR) methodology, based on empirical evidence from the Greek mining industry, is discussed to identify the KGs appearing in mining operations and [...] Read more.

The objective of the paper is an introductory discussion on the knowledge gaps (KGs) observed in mining operations. A qualitative research (QLR) methodology, based on empirical evidence from the Greek mining industry, is discussed to identify the KGs appearing in mining operations and investigate the cause and criticality of each KG. Recommendations for the extension and integration of the methodology as a tool appropriate for introducing knowledge management (KM) in Greek mining organizations are provided. Full article

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6 pages, 231 KiB

Open AccessProceeding Paper

Industry 4.0 Roadmap for the Mining Sector

by Doris Skenderas and Chrysa Politi

Mater. Proc. 2023, 15(1), 16; https://doi.org/10.3390/materproc2023015016 - 16 Oct 2023

Viewed by 1217

Abstract

The mining industry is by nature a challenging and demanding sector. Beyond ore extraction, management, processing, and transportation are involved in mining activities. Mining operations, often located in geographically remote and isolated areas, are capital-intensive and have substantial environmental and social impacts. The [...] Read more.

The mining industry is by nature a challenging and demanding sector. Beyond ore extraction, management, processing, and transportation are involved in mining activities. Mining operations, often located in geographically remote and isolated areas, are capital-intensive and have substantial environmental and social impacts. The sector is considered mature and conservative regarding innovation. Nevertheless, its multidimensional nature, combined with declining ore grades and the increased demand for scarce resources, generates an imperative for innovation and the adoption of new technologies. In line with Industry 4.0, Mining 4.0 is the framework for integrating technologies such as the Internet of Things (IoT), automated drones, 3D printing, robotics, sensors, data analytics for monitoring, and performance evaluation in the mining industry. The legislation, the regulatory framework, and governance arrangements often create barriers to the adoption of innovative concepts in the mining sector. This study is an overview of gaps, barriers, inefficiencies, and enablers in the regulatory framework of the mining sector in relation to the utilization of new technologies. Full article

7 pages, 1991 KiB

Open AccessProceeding Paper

Machine Learning Techniques to Model and Predict Airflow Requirements in Underground Mining

by Maria Karagianni and Andreas Benardos

Mater. Proc. 2023, 15(1), 17; https://doi.org/10.3390/materproc2023015017 - 16 Oct 2023

Viewed by 646

Abstract

This paper analyzes the airflow requirements of underground operations and the accurate assessment of future conditions so as to effectively adjust ventilation parameters. More particularly, ML techniques are utilized to capture patterns or prevailing conditions and to be able to generalize/predict future conditions [...] Read more.

This paper analyzes the airflow requirements of underground operations and the accurate assessment of future conditions so as to effectively adjust ventilation parameters. More particularly, ML techniques are utilized to capture patterns or prevailing conditions and to be able to generalize/predict future conditions managed via the ventilation system. The case examined is about underground bauxite mining operations, the ventilation characteristics and requirements of which have been firstly developed and modelled into a validated digital twin. With this twin model, several scenarios are developed and evaluated and more importantly data are gathered, allowing for the training of the ML algorithms used to assess and predict the required ventilation airflow, taking into account air quality data, the number of workers, and machine fleet. Full article

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6 pages, 931 KiB

Open AccessProceeding Paper

A Concise Review of Carbon Dioxide Storage in Depleted Oil Fields of Prinos in Northern Greece

by Georgios C. Avraam and Konstantinos I. Vatalis

Mater. Proc. 2023, 15(1), 18; https://doi.org/10.3390/materproc2023015018 - 17 Oct 2023

Viewed by 838

Abstract

This paper examines the prospects of carbon dioxide capture and storage in depleted oil wells in Prinos in Kavala, Northern Greece. The need to store this gas arises from measures to minimize carbon emissions into the atmosphere to be climate-neutral by 2050 and [...] Read more.

This paper examines the prospects of carbon dioxide capture and storage in depleted oil wells in Prinos in Kavala, Northern Greece. The need to store this gas arises from measures to minimize carbon emissions into the atmosphere to be climate-neutral by 2050 and establish an economy with net-zero greenhouse gas emissions. Greece, as part of the European Green Deal, has adopted the EU’s strategy in line with its commitment to global climate action under the Paris Agreement. The possibility of reusing the produced carbon dioxide through the oil industry is being investigated, a method that has been the subject of studies worldwide in recent decades. Incorporating evidence from studies, scientific research, and publications, the paper demonstrates that CO₂ storage is an affordable and technologically compatible method with existing gas storage methods. The resulting economic and environmental benefits are highlighted, and reference is also made to the possibility of exploiting similar reservoirs in the wider area. In brief, the greenhouse effect will be reduced, and oil fields “Epsilon” and “Ammodis” are going to be extracted; hence, the financial gain should be increased. The importance of making such an investment at this particular period and the environmental and economic benefits for Greece and the EU are pointed out. Full article

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5 pages, 2095 KiB

Open AccessProceeding Paper

Factors Affecting the Properties of Slag-Based Alkali-Activated Materials

by Konstantinos Komnitsas, Vasiliki Karmali, Dimitra Vathi and Eleftherios Kaklamanos

Mater. Proc. 2023, 15(1), 19; https://doi.org/10.3390/materproc2023015019 - 24 Oct 2023

Viewed by 382

Abstract

This study, carried out in the frame of the Horizon Europe ENICON project, “Sustainable processing of Europe’s low grade sulphidic and lateritic Ni/Co ores and tailings into battery grade metals”, evaluates the properties of alkali-activated materials (AAMs) produced from slag obtained from the [...] Read more.

This study, carried out in the frame of the Horizon Europe ENICON project, “Sustainable processing of Europe’s low grade sulphidic and lateritic Ni/Co ores and tailings into battery grade metals”, evaluates the properties of alkali-activated materials (AAMs) produced from slag obtained from the Euronickel ferronickel plant at Kavadarci, Republic of N. Macedonia. The activating solution comprises sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) solutions. The effect of various operating parameters, i.e., the molarity of the activating solution (6–10 mol/L), pre-curing period (24–96 h), curing temperature (20–80 °C), and aging period (7–96 days) on the compressive strength, density, porosity and water absorption of the produced AAMs, was initially assessed. The first experimental results indicate that the produced AAMs acquired compressive strength exceeding 40 MPa after curing at 80 °C and aging for 7 days. This value increased to higher than 55 and 70 MPa when the aging period was 28 and 96 days, respectively. Full article

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7 pages, 1445 KiB

Open AccessProceeding Paper

Using Natural and Synthetic Zeolites for Mine Soils Clean-Up

by Maria Roulia and Charalampos Vasilatos

Mater. Proc. 2023, 15(1), 20; https://doi.org/10.3390/materproc2023015020 - 24 Oct 2023

Viewed by 497

Abstract

Acid mine drainage originates from mining waste, tailings and overburden being exposed to air and water; it is also observed in abandoned mines, characterized by high acidity and increased concentrations of sulfate and heavy metals. It is considered a notorious pollutant, mostly affecting [...] Read more.

Acid mine drainage originates from mining waste, tailings and overburden being exposed to air and water; it is also observed in abandoned mines, characterized by high acidity and increased concentrations of sulfate and heavy metals. It is considered a notorious pollutant, mostly affecting superficial and ground water quality. Until 1977, Lavrion mines have been the heart of dynamic Greek mining and extractive metallurgy. The present paper discusses the possibility of using low-cost eco-friendly materials, i.e., natural and synthetic zeolites for the in situ rehabilitation of Lavrion mine soil. Na-P1 synthetic zeolite prepared from Meliti fly ash and two natural zeolites from Samos tuffs mostly containing clinoptilolite and mordenite, respectively, were employed. The results indicated that all three aluminosilicates alleviated two basic soil parameters closely correlated with fertility, i.e., high acidity and low CEC. Regarding toxic metals leaching, Na-P1 synthetic zeolite proved more efficient, reducing heavy metal contents in the leachates by 38%, 72%, 61%, 67%, 77% and 33% for Pb, Cd, Zn, Cu, Mn and Fe, respectively. This was attributed to both the increased pH and CEC values of the Na-P1 zeolite. Between the Samos zeolites, the richest in mordenite exhibited the better performance. Full article

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7 pages, 948 KiB

Open AccessProceeding Paper

A Comparative Study on the Properties of Volcanic Rocks from the Aegean Islands, Greece, for Utilization as Pozzolanic Additives in Cement

by Theodoros Sainis, Glikeria Kakali, Panagiotis Pomonis and Charalampos Vasilatos

Mater. Proc. 2023, 15(1), 21; https://doi.org/10.3390/materproc2023015021 - 24 Oct 2023

Viewed by 544

Abstract

This comparative study investigates the pozzolanic potential of volcanic rocks sourced from the Aegean Islands, Greece, as additives in cement. The utilization of volcanic materials as pozzolanic additives has gained interest due to its ability to enhance the performance and sustainability of cement-based [...] Read more.

This comparative study investigates the pozzolanic potential of volcanic rocks sourced from the Aegean Islands, Greece, as additives in cement. The utilization of volcanic materials as pozzolanic additives has gained interest due to its ability to enhance the performance and sustainability of cement-based materials. Pumice of Pleistocene age from Gyali Island, Pleistocene and Pliocene rhyolites from Kos Island, the Upper Miocene zeolitized rhyolite of Samos Island, and pumiceous tuffs of Upper Miocene age from Chios Island were sampled, and their chemical, mineralogical, and physical properties were analyzed. The results were compared to identify the most suitable for use as pozzolana in cement-based applications. The reactive silica determinations showed that all the rocks studied satisfy the EN 197 1-2 specification for reactive SiO₂ content > 25%. Despite their lower Chapelle values, the Pliocene and Pleistocene rhyolites (perlites) of Kos Island (Kefalos area) exhibit reactive silica values higher than 25%, acceptable LOI, and, due to their homogeneity and specifications compliance along with their wide spatial extend, may be considered the most promising among the rock formations studied as a natural pozzolana resource suitable for the cement industry. Full article

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7 pages, 627 KiB

Open AccessProceeding Paper

Application of International Standards to Evaluate the Potential of Sustainable Secondary Production of Tin and Tungsten in Portugal

by Md Ariful Islam, José E. Brito Iria, Georg Meissner, George Barakos and Helmut Mischo

Mater. Proc. 2023, 15(1), 22; https://doi.org/10.3390/materproc2023015022 - 24 Oct 2023

Viewed by 527

Abstract

The ambitious movement towards industry 5.0 technologies and the green transition drives the efforts towards securing critical metals’ supply chains globally. In Europe, highly economically important Tin and Tungsten are raising concerns regarding supply security due to geographical reserves’ uniformity and socio-political reluctance [...] Read more.

The ambitious movement towards industry 5.0 technologies and the green transition drives the efforts towards securing critical metals’ supply chains globally. In Europe, highly economically important Tin and Tungsten are raising concerns regarding supply security due to geographical reserves’ uniformity and socio-political reluctance to mining. Nevertheless, mines that have seized operations in Portugal due to not being sustainable in the past are attracting renewed attention for further exploitation due to growing market demand and reclamation efforts for environmental concerns. Such abandoned resources need to be reassessed for their feasibility from economic, social, and environmental perspectives to ensure sustainable exploitation. Presenting the production criticality of Tin and Tungsten, this study implements the United Nations Framework Classification for Resources (UNFC) to assess the viability of abandoned mines and tailings dumps in Portugal, considering the indicators of Sustainable Development Goals (SDGs). The work indicates that Portugal’s abandoned Vale das Gatas Tin and Tungsten mine has good potential for further development. Furthermore, social perception towards new and abandoned mining is evaluated by collecting opinions from different parts of the country. It has been identified that sustainable technology and job opportunities are the driving parameters for the social acceptance of mining projects in Portugal. Full article

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6 pages, 2894 KiB

Open AccessProceeding Paper

Alluvial Gold Mining from Argonauts to Agricola

by Spyridon Mathioudakis, George Xiroudakis, Evangelos Petrakis and Emmanouil Manoutsoglou

Mater. Proc. 2023, 15(1), 23; https://doi.org/10.3390/materproc2023015023 - 25 Oct 2023

Viewed by 422

Abstract

This work examines alluvial gold deposit mining and processing methods from the Argonautic expedition until the Renaissance. According to Greek mythology, the mountain rivers of Colchis (Georgia) carried coarse sand and gold particles, which were washed in special wooden sluice boxes. The finer [...] Read more.

This work examines alluvial gold deposit mining and processing methods from the Argonautic expedition until the Renaissance. According to Greek mythology, the mountain rivers of Colchis (Georgia) carried coarse sand and gold particles, which were washed in special wooden sluice boxes. The finer fractions were held in the lower part of the device, which was lined with sheepskin. Using a sheepskin to extract gold from riverbeds gave rise to the myth of the Golden Fleece. Afterwards, during the Roman Empire period, the mining of alluvial gold was performed manually until the discovery of hydraulic mining, a technique that contributed to a massive increase in production. At the same time, the Romans employed various techniques to separate the metals from the total mass of the ore. Gold refining was carried out through cupellation and the mercury amalgamation process. During the Renaissance, Georgius Bauer Agricola wrote De Re Metallica, one of the essential machinery books in mining in the 16th century. He developed a new type of pump to remove water, the uncontrolled flow of which caused significant problems in the underground mining process. The bucket chain pump, the “pater noster” pump, and the piston pump are some of the most innovative devices he presented in his work. Also, Agricola extensively referenced the recovery techniques for gold and other precious metals during the Archaic period that helped preserve the myth of the Argonautic expedition and the Golden Fleece. Full article

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12 pages, 5559 KiB

Open AccessProceeding Paper

Critical Raw Material Resource Potentials in Europe

by Antje Wittenberg and Daniel de Oliveira

Mater. Proc. 2023, 15(1), 24; https://doi.org/10.3390/materproc2023015024 - 30 Oct 2023

Viewed by 1361

Abstract

The vulnerability of economies and the associated familiar lifestyles have led to numerous policy measures in Europe. The proposed Critical Raw Materials Act (CRMA) sets indicative targets for 2030. A sustainable change in the supply situation requires the targeted exploration of raw materials [...] Read more.

The vulnerability of economies and the associated familiar lifestyles have led to numerous policy measures in Europe. The proposed Critical Raw Materials Act (CRMA) sets indicative targets for 2030. A sustainable change in the supply situation requires the targeted exploration of raw materials precisely within the framework of national geological research of suitable detail and in advance of entrepreneurial raw material projects. EU projects like GeoERA assist in shaping the tailor-made exploration programs fit for purpose. GeoERA scientific projects like FRAME and MINDeSEA completed, and updated existing mineral data on CRM are publicly available through EuroGeoSurveys’ European Geological Data Infrastructure (EGDI). Full article

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5 pages, 1779 KiB

Open AccessProceeding Paper

An Assessment of Hand-Held XRF Analyser Performance for the Characterisation of Aluminium Scrap

by Angeliki Ntourntoureka, Michail Galetakis and Vasileios Deligiorgis

Mater. Proc. 2023, 15(1), 25; https://doi.org/10.3390/materproc2023015025 - 03 Nov 2023

Viewed by 307

Abstract

The characterisation of aluminium scrap plays a crucial role in its recycling, and hand-held X-ray fluorescence (XRF) analysers offer a portable and efficient solution for on-site analysis. This study focuses on assessing the performance of a hand-held XRF analyser for the characterisation of [...] Read more.

The characterisation of aluminium scrap plays a crucial role in its recycling, and hand-held X-ray fluorescence (XRF) analysers offer a portable and efficient solution for on-site analysis. This study focuses on assessing the performance of a hand-held XRF analyser for the characterisation of aluminium scrap using the gage repeatability and reproducibility (Gage R&R) method. Full article

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6 pages, 1604 KiB

Open AccessProceeding Paper

Effect of By-Pass Filter Dust on Durability of Self-Compacting Concrete

by Andreas Kounadis, Konstantinos Tsivolas and Efstratios Badogiannis

Mater. Proc. 2023, 15(1), 26; https://doi.org/10.3390/materproc2023015026 - 03 Nov 2023

Cited by 1 | Viewed by 337

Abstract

By-pass filter dust (BPD) is one of the main by-products produced and collected during the cement production process, being a potential atmospheric and subsoil pollutant. In this paper, the utilization of BPD by partially replacing a conventional filler such as marble powder with [...] Read more.

By-pass filter dust (BPD) is one of the main by-products produced and collected during the cement production process, being a potential atmospheric and subsoil pollutant. In this paper, the utilization of BPD by partially replacing a conventional filler such as marble powder with regard to the durability and transport properties of Self-Compacting Concrete (SCC) is thoroughly investigated. More specifically, BPD’s incorporation effect was evaluated after conducting a series of tests related to SCCs’ water absorption, sorptivity, water permeability, chloride diffusion coefficient, carbonation and freeze and thaw resistance. The above-mentioned test results demonstrated that BPD, thanks to its high pozzolanic reactivity in conjunction with its filler effect, contributed to the production of SCC of a denser cementitious matrix, which, in turn, lead to improved durability. Full article

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4 pages, 988 KiB

Open AccessProceeding Paper

Investigating the Recovery of Noble Metals from Single-Use Medical Technology-Specific Waste Streams

by Evgenios Kokkinos, Domna Merachtsaki, Aggeliki Lampou, Charikleia Prochaska, Effrosyni Peleka, Konstantinos Simeonidis, Georgios Vourlias and Anastasios Zouboulis

Mater. Proc. 2023, 15(1), 27; https://doi.org/10.3390/materproc2023015027 - 03 Nov 2023

Viewed by 364

Abstract

Noble metals (Pt, Ir, Au, Ta, etc.) have found several applications in specific medical technology products since they present inertness and visibility when examined via fluoroscopy by an external observer/operator. These products are usually applied as single-use materials and, as a result, the [...] Read more.

Noble metals (Pt, Ir, Au, Ta, etc.) have found several applications in specific medical technology products since they present inertness and visibility when examined via fluoroscopy by an external observer/operator. These products are usually applied as single-use materials and, as a result, the corresponding waste streams may be quite rich in valuable metals. In this work, it was proven that noble metals can be recovered from such waste streams. Initially, pyrolysis may completely remove the plastic covering of medical products. In addition, selective dissolution of noble metals can be achieved by applying different inorganic acids or their mixtures. Full article

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10 pages, 2299 KiB

Open AccessProceeding Paper

Recycling Concrete to Aggregates. Implications on CO₂ Footprint

by Ioannis Bampanis and Charalampos Vasilatos

Mater. Proc. 2023, 15(1), 28; https://doi.org/10.3390/materproc2023015028 - 03 Nov 2023

Cited by 1 | Viewed by 1151

Abstract

Over the last decades, the needs of the contemporary way of life and the ongoing population growth have affected the construction industry by causing rapid development of the sector. This accretion combined with the challenging management of construction and demolition waste (CDW) resulted [...] Read more.

Over the last decades, the needs of the contemporary way of life and the ongoing population growth have affected the construction industry by causing rapid development of the sector. This accretion combined with the challenging management of construction and demolition waste (CDW) resulted in an increasing amount of waste being produced as well as an associated impact on the environment. Those impacts render their management necessary, in order to contribute to the concepts of sustainable development and Circular economy. The present paper discusses the usage of recycled aggregates (RAs) from CDW, in correlation with natural aggregates (NA) in the manufacture of concrete, both from quality and environmental perspectives. Upon analysis of the physical–chemical and mechanical properties, a replacement ratio of RAs of 50% was suggested, considering two factors: (1) the highest acceptable decrease in aggregate properties; and (2) the higher contribution to the environment, which is also accepted by the EN-12620 standard. Furthermore, it was calculated that the net carbon balance of aggregate utilization, based on the above scenario, is approximately 20% lower compared to NA. Full article

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6 pages, 237 KiB

Open AccessProceeding Paper

Potential Benefits from Carbon Capture Utilisation and Methanol Production in Magnesite Processing Line

by Antonis Peppas, Doris Skenderas, Chrysa Politi and Dimitris Sparis

Mater. Proc. 2023, 15(1), 29; https://doi.org/10.3390/materproc2023015029 - 03 Nov 2023

Viewed by 353

Abstract

Magnesite (MgCO₃) is a carbonate mineral, which is calcinated and further processed to generate magnesia (MgO) refractory materials and other products. MgCO₃ products are mainly used in the iron and steel industries, in cement manufacture as a refractory material, and [...] Read more.

Magnesite (MgCO₃) is a carbonate mineral, which is calcinated and further processed to generate magnesia (MgO) refractory materials and other products. MgCO₃ products are mainly used in the iron and steel industries, in cement manufacture as a refractory material, and as raw materials in the chemical industry, in agriculture, etc. The MgO refractory industry is linked with carbon dioxide (CO₂) emissions released not only from the fuel combustion in the production process of MgCO₃, but also from its decomposition. Even though the exact amount of CO₂ eq. depends on the specific product, there is the urge to minimise the CO₂ emitted from MgO₃ processing. Carbon capture and utilisation (CCU) technology has gained ground in recent years in this industry. The incorporation of CCU systems for the processing of fuel gases has been investigated as a means to contribute further to the decarbonisation of the extractive industries. The CO₂ captured through this process can be converted into a value-added chemical or liquid fuel. This study aims to overview the impact of the application of CCU technologies in MgCO₃ processing lines and the conversion of the captured CO₂ to methanol (MeOH). In this regard, the strengths (S), the weaknesses (W), the opportunities (O), and the threats (T) of the proposed concept will be discussed in a SWOT analysis coupled with the environmental and techno-economic aspects. Full article

6 pages, 222 KiB

Open AccessProceeding Paper

Potential Application of RES and Underground H₂ Storage in Abandoned Mines

by Antonis Peppas, Sotiris Kottaridis and Chrysa Politi

Mater. Proc. 2023, 15(1), 30; https://doi.org/10.3390/materproc2023015030 - 03 Nov 2023

Viewed by 584

Abstract

Mining operations, as with all industrial operations, have a significant impact on the environment both through the generation of waste and through landscape change. In view of this, pioneering and sustainable post-mining technologies are demanded to reduce environmental impact. Clean energy can be [...] Read more.

Mining operations, as with all industrial operations, have a significant impact on the environment both through the generation of waste and through landscape change. In view of this, pioneering and sustainable post-mining technologies are demanded to reduce environmental impact. Clean energy can be part of the solution, with emphasis on the penetration of renewable energy sources (RES) for the mitigation of greenhouse gases. RES production is inherently fluctuating, at times being insufficient while others creating energy surpluses. Converting a mining site into a parallel renewable energy generation facility can provide new job opportunities and economic value, as well as contribute to a more secure energy supply. Abandoned mines present a viable option for the installation of such systems, exploiting their underground facilities for safe storage. In this regard, the underground facilities can be exploited for green hydrogen (H₂) energy storage systems to be used on-site in times of RES deficits. Underground H₂ storage has many advantages over surface storage, including safer storage, smaller footprints, a larger storage capacity, and a lower cost. The re-use of pre-existing infrastructure and land availability for deploying solar parks also offers innovative ways to generate clean energy. This study examines the potential of repurposing abandoned mines in the form of renewable energy generation facilities in order to improve their environmental impact and move quickly towards sustainable and innovative mining throughout Europe. Full article

8 pages, 278 KiB

Open AccessProceeding Paper

An Overview of Quality Assessment Methods for Water and Soil in Mining Regions

by Ioanna Petropoulou, Maria-Sotiria Frousiou and Eleni Vasileiou

Mater. Proc. 2023, 15(1), 31; https://doi.org/10.3390/materproc2023015031 - 03 Nov 2023

Viewed by 480

Abstract

Mining activities are a form of severe anthropogenic stress and result in water and soil contamination in mining sites. A decline in the quality of water affects humans directly through water consumption or indirectly through contaminated food consumption. Soil pollution has an immediate [...] Read more.

Mining activities are a form of severe anthropogenic stress and result in water and soil contamination in mining sites. A decline in the quality of water affects humans directly through water consumption or indirectly through contaminated food consumption. Soil pollution has an immediate consequence on farming products and soil fertility and may affect water resources. Monitoring environmental conditions and changes is essential for mining industries and local authorities. The aim of this paper is to review different methods, their purpose, and adequacy, for the environmental management of mining areas. Full article

7 pages, 1158 KiB

Open AccessProceeding Paper

Application of Multi-Criteria Decision-Making Methods in Mineral Processing—A Review

by Zoran Štirbanović, Dragiša Stanujkić, Jovica Sokolović and Ivana Ilić

Mater. Proc. 2023, 15(1), 32; https://doi.org/10.3390/materproc2023015032 - 03 Nov 2023

Viewed by 467

Abstract

Multi-criteria decision-making (MCDM) methods represent an efficient mathematical tool for making selections between several alternatives which are seemingly similar and also when a large number of influential criteria need to be taken into consideration. In other words, MCDM methods make difficult choices easier, [...] Read more.

Multi-criteria decision-making (MCDM) methods represent an efficient mathematical tool for making selections between several alternatives which are seemingly similar and also when a large number of influential criteria need to be taken into consideration. In other words, MCDM methods make difficult choices easier, so that was the reason why they found applications in various areas of life, industry, science, etc. In mineral processing, when conducting scientific research or in industrial practice, it is often necessary to make different kinds of decisions based on several often-conflicting parameters such as technological, economic and environmental parameters. Making the wrong choices can affect the industrial process, result in additional expenses and endanger the health of workers and the environment, thus the application of MCDM methods can be the solution and give additional help in decision-making processes. In the past few decades, a large number of MCDM methods were developed, and some of them have found application in mineral processing for different purposes, such as the selection of various equipment (flotation machines, crushers, etc.), the selection of flotation collectors and other reagents used in mineral processing, and the selection of technologies for processing different raw materials, grinding circuits, and so on. In this paper, a comprehensive overview of the used MCDM methods and their applications regarding mineral preparation and processing will be given. Full article

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7 pages, 4669 KiB

Open AccessProceeding Paper

Mapping the Soil Chemical Properties of the Sarigkiol Basin, Western Macedonia, Greece, in View of the Transition to the Post-Lignite Era

by Despoina Psarraki, Panagiotis Papazotos, Eleni Vasileiou and Maria Perraki

Mater. Proc. 2023, 15(1), 33; https://doi.org/10.3390/materproc2023015033 - 06 Nov 2023

Viewed by 427

Abstract

The chemical properties of soils in the Sarigkiol Basin, Western Macedonia, Greece, were studied to investigate the potential for new land uses in post-mining areas. An extensive dataset of chemical parameters was analyzed in a total of 34 representative soil samples from the [...] Read more.

The chemical properties of soils in the Sarigkiol Basin, Western Macedonia, Greece, were studied to investigate the potential for new land uses in post-mining areas. An extensive dataset of chemical parameters was analyzed in a total of 34 representative soil samples from the Sarigkiol Basin. The data were processed using statistical methods (Spearman’s correlation coefficient (CC), factor analysis (FA), and hierarchical cluster analysis (HCA)) and thematic maps. Soil properties were assessed using different geoenvironmental indices (e.g., pollution load index (PLI), enrichment factor (EF), and geoaccumulation index (I_geo)). The results show that geogenic factors are crucial for soil chemical properties and that agricultural activities play an important role in soil contamination. The mapping of soil properties in such a mining area is of great interest for the next step of the transition to the post-lignite era and new land uses for sustainable rehabilitation. Full article

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13 pages, 3358 KiB

Open AccessProceeding Paper

Characterization of Waste from the Dicalcium Phosphate Industry as a Potential Secondary Source of Rare Earth Elements

by Marcin Płachciak, Fidel Grandia, Vladimir Roddatis and Marcin Daniel Syczewski

Mater. Proc. 2023, 15(1), 34; https://doi.org/10.3390/materproc2023015034 - 06 Nov 2023

Viewed by 530

Abstract

Fluorite-rich sludge is the main waste from dicalcium phosphate (DCP) production. This sludge consists of 40–60% of CaF₂, which precipitates during the reaction between fluorapatite (the main component of raw phosphorite material) and HCl. In addition, the sludge contains elevated amounts [...] Read more.

Fluorite-rich sludge is the main waste from dicalcium phosphate (DCP) production. This sludge consists of 40–60% of CaF₂, which precipitates during the reaction between fluorapatite (the main component of raw phosphorite material) and HCl. In addition, the sludge contains elevated amounts of critical elements such as REEs. In this study, two industrial sites producing DCP in Spain were studied to assess the potential valorization of these sludges. Currently, almost 2 Mt of waste remains landfilled in these sites. The concentrations of Y, La, Nd, Dy, and Gd found within the residues are about 1100 ppm, 450 ppm, 300 ppm, 80 ppm, and 75 ppm, respectively. Fluorite, being the host mineral of the REEs, occurs as very fine-grained spherules (<5 μm) that are smaller than other minerals in the waste (quartz, gypsum), favoring the options of hydrometallurgical separation. REEs extraction from the fluorite could be an advantageous option, if separated from uranium, which is the main environmental concern of the future valorization of this kind of waste. Full article

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5 pages, 234 KiB

Open AccessProceeding Paper

Preliminary Assessment of Social License to Operate (SLO) and Corporate Communication in Four European Lithium Projects

by Toni Eerola and Konstantinos Komnitsas

Mater. Proc. 2023, 15(1), 35; https://doi.org/10.3390/materproc2023015035 - 06 Nov 2023

Viewed by 925

Abstract

Lithium, that is now exclusively produced outside the European Union (EU), is needed urgently for the green energy transition. The EU has promising lithium projects; however, the social license to operate (SLO) is important for their long-term viability. In this paper, four lithium [...] Read more.

Lithium, that is now exclusively produced outside the European Union (EU), is needed urgently for the green energy transition. The EU has promising lithium projects; however, the social license to operate (SLO) is important for their long-term viability. In this paper, four lithium projects are preliminary assessed using data from the literature and media regarding their SLO. The projects that aim for hard rock lithium production are (i) the Rapasaari project owned by Sibanye-Stillwater Keliber Oy in Kaustinen, western Finland, (ii) the Mina do Barroso project, owned by Savannah Resources, in northern Portugal, (iii) the St. Austell project, owned by Cornish Lithium plc, in Cornwall, UK, and (iv) the Emili project, owned by Imerys, in Beauvoir (Allier) in western France. The respective corporate websites were searched, regarding their languages while the companies’ SLO approaches and strategies were also analyzed. Full article

6 pages, 636 KiB

Open AccessProceeding Paper

Preliminary Environmental Assessment of Carbonated Slags as a Carbon Capture, Utilization, and Storage Materials (CCUS)

by Ponnapat Watjanatepin, Laura Steinwidder, Anthony de Schutter, Giuseppe Granata, Sara Vicca, Tom Van Gerven and Karel Van Acker

Mater. Proc. 2023, 15(1), 36; https://doi.org/10.3390/materproc2023015036 - 06 Nov 2023

Viewed by 380

Abstract

The steel manufacturing industry is one of the most concentrated anthropogenic carbon-emitting point sources that is still expected to increase further each year. Moreover, steel slags are also generated at a rate of 10–20% of the total crude steel production. The possibility to [...] Read more.

The steel manufacturing industry is one of the most concentrated anthropogenic carbon-emitting point sources that is still expected to increase further each year. Moreover, steel slags are also generated at a rate of 10–20% of the total crude steel production. The possibility to valorize both the flue gases and steel slags through mineral carbonation has garnered the spotlight in recent research on waste valorization and sustainable steel production practices. Mineral carbonation of steel slags leads to the stable adsorption of carbon dioxide onto the surface of the steel slags. Nonetheless, it is essential to assess whether the environmental benefits resulting from the mineral carbonation process would outweigh the environmental burdens associated with the transformation and carbonation processes. To this end, this study aims to illustrate the potential environmentally friendly industrial waste valorization pathway by performing life cycle assessment (LCA) to obtain the environmental impacts of carbonated steel slags. The environmental impacts are calculated by the ReCiPe 2016 midpoint methodology. Furthermore, contribution analysis for the carbonated slag production is provided. This study also illustrates a comparison of steel slag carbonation with pure carbon and flue gases by means of scenario analysis. The results of this study should provide insights into the possibility of employing mineral carbonation on industrial wastes in the metallurgical sector as well as highlight the possible areas of improvement for prospective scale-ups. To this end, the results of this study could contribute to the improvement of the environmental sustainability of the steel manufacturing sector. Full article

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5 pages, 1387 KiB

Open AccessProceeding Paper

Magnetite–Hematite Characterization at Micron Scale with Implications for Metallurgical Processing and Decarbonization

by Beate Orberger, Christiane Wagner, Omar Boudouma, Nicolas Rividi, Christine Bauer, Rebecca Wagner, Ghasem Nabatian, Maryam Honarmand and Iman Monsef

Mater. Proc. 2023, 15(1), 37; https://doi.org/10.3390/materproc2023015037 - 06 Nov 2023

Viewed by 493

Abstract

Magnetite deposits represent important iron ore resources. Selective sorting of valuables from gangue and targeting of potential critical metals that can be recovered from waste streams must be implemented from the exploration and excavation steps onwards. Optical and scanning electron microscopy, electron microprobe [...] Read more.

Magnetite deposits represent important iron ore resources. Selective sorting of valuables from gangue and targeting of potential critical metals that can be recovered from waste streams must be implemented from the exploration and excavation steps onwards. Optical and scanning electron microscopy, electron microprobe analysis, dual-energy X-ray transmission, and computed tomography were applied to determine the mineralogy and classify the iron oxides of different iron ore types. These characteristics can be used for sorting at the exploration and extraction steps to reduce unvaluable materials at the loading and hauling steps, which contribute about 50% of the greenhouse gas emissions of the iron ore mining and mineral processing sector. These data also contribute to fine-tuning mineral processing parameters. Full article

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5 pages, 666 KiB

Open AccessProceeding Paper

Thermal Treatment of Serpentinized Olivine Wastes, Obtained from Chromite Mineral Enrichment Operations, as an Example of Circular Economy in the Mining Sector

by Evgenios Kokkinos, Effrosyni Peleka and Anastasios Zouboulis

Mater. Proc. 2023, 15(1), 38; https://doi.org/10.3390/materproc2023015038 - 07 Nov 2023

Viewed by 374

Abstract

Chromite ore occurs mainly in ophiolitic mineral complexes and within ultrabasic rocks. As a result, the mining and enrichment processes applied to this ore lead to the production of large amounts of ultrabasic rocks, considered to be a waste stream. These wastes are [...] Read more.

Chromite ore occurs mainly in ophiolitic mineral complexes and within ultrabasic rocks. As a result, the mining and enrichment processes applied to this ore lead to the production of large amounts of ultrabasic rocks, considered to be a waste stream. These wastes are mainly various structures of olivine and serpentine (i.e., hydrous structures of olivine). The ultrabasic rocks may be considered a by-product of this process, following the framework of the circular economy, but the presence of serpentine degrades their quality. In this work, it was proven that the thermal treatment of ultrabasic rock samples may eliminate the serpentine content. Full article

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9 pages, 4160 KiB

Open AccessProceeding Paper

RIS Internship–Sustainable and Structured Internship Programme for Raw Materials Master’s Students and Organizations from RIS Regions

by Sibila Borojević Šoštarić, Kristina Koret, Vječislav Bohanek and Ferenc Madai

Mater. Proc. 2023, 15(1), 39; https://doi.org/10.3390/materproc2023015039 - 07 Nov 2023

Viewed by 1024

Abstract

The deficit of graduates working in the core raw materials sectors will significantly impact raw materials organizations in European RIS regions. The RIS Internship programme aims to improve professional opportunities for RIS raw materials students, familiarize the future young professionals with the work [...] Read more.

The deficit of graduates working in the core raw materials sectors will significantly impact raw materials organizations in European RIS regions. The RIS Internship programme aims to improve professional opportunities for RIS raw materials students, familiarize the future young professionals with the work environment and real-life challenges, and trigger their intrinsic interest for the development of a future career in the sector. The overall objectives of the programme are to increase the students’ entrepreneurial and business skills, boost the employment of the RM graduates within the hosting organizations, and leverage the regional brain drain. Eligible students and organizations are coming from core raw materials professions: mining, geosciences and geotechnology, geosciences, material science, extractive waste management, and metallurgy and recycling, all belonging to the STEM area. The territorial coverage includes European RIS countries: Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, the Czech Republic, Estonia, Greece, Hungary, Italy (southern part) Latvia, Lithuania, Montenegro, North Macedonia, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Turkey, and Ukraine. The programme was implemented via the recorded pretraining webinars of students and supervisors, the development of an RIS Internship guide for successful RIS Internship implementation, and an on-line matchmaking platform, making it structured and sustainable with minimum future investment. Full article

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8 pages, 2002 KiB

Open AccessProceeding Paper

Science to Business Transfer Training Program—The Involvement of Universities

by Malwina Kobylańska and Agnieszka Urbańska-Ciszek

Mater. Proc. 2023, 15(1), 40; https://doi.org/10.3390/materproc2023015040 - 08 Nov 2023

Viewed by 379

Abstract

The successful commercialization of the results of research works, R&D projects and inventions, as well as the cooperation between research centres, industry and business, is becoming commonplace and crucial in regional development. Regardless of the scientific level of the research results, the utility [...] Read more.

The successful commercialization of the results of research works, R&D projects and inventions, as well as the cooperation between research centres, industry and business, is becoming commonplace and crucial in regional development. Regardless of the scientific level of the research results, the utility of these results and the adopted business model for their implementation are the key factors determining the market success. Currently, the recognized skills and competencies of academic staff at Eastern and Southeastern European universities in the field of the implementation and commercialization of scientific research results do not seem sufficient. This article presents the methodology, development and results of the tailor-made Science to Business transfer program implemented within the TrainESEEv.2 ‘Training the trainers in East and Southeast Europe’ project, with a focus on the Raw Materials sector needs. Full article

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7 pages, 2192 KiB

Open AccessProceeding Paper

Fast and Cost-Effective Quantitative Assessment of the Chemical and Mineral Composition of Heavy Mineral Sands Ores: Application of the New SOLSA Combined XRF-XRD Analytical Solution to the Grande Cote Operation Ti-Zr Mine

by Maud Herbelin, Sylvain Delchini, Henry Pillière, Luca Lutterotti, Marion Nicco, Moctar Dia, Monique Le Guen and Thomas Riegler

Mater. Proc. 2023, 15(1), 41; https://doi.org/10.3390/materproc2023015041 - 08 Nov 2023

Viewed by 641

Abstract

Mine optimisation and anticipation of ore behaviour in the mineral processing and separation circuits are major economic drivers for all mining operations. Recent methodological developments with the inception of geometallurgy across multiple commodities have highlighted the importance of mineralogy in addition to elemental [...] Read more.

Mine optimisation and anticipation of ore behaviour in the mineral processing and separation circuits are major economic drivers for all mining operations. Recent methodological developments with the inception of geometallurgy across multiple commodities have highlighted the importance of mineralogy in addition to elemental grades. In the last few decades, many quantitative tools have been developed, mostly SEM-based such as QEMSCAN^®, and used to provide the quantitative mineralogical compositions of samples. Their main drawback is the time and cost associated with sample preparation, acquisition time, and data QA/QC. The combined XRF-XRD of the SOLSA (Sonic On-Line drilling and Sampling Analysis) analytical solution brings a new methodology able to produce quantitative mineralogical and geochemical data at a speed compatible with a production environment. Its range of applications covers the entire life of a mining operation, from the initial exploration stage to mineral processing control, as well as waste management and environmental monitoring. Full article

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8 pages, 1272 KiB

Open AccessProceeding Paper

Water and Alkali Leaching for Simultaneous Iron and Alumina Separation from Hydrogen-Reduced Bauxite Residue-Calcite Pellets

by Manish Kumar Kar, Casper van der Eijk and Jafar Safarian

Mater. Proc. 2023, 15(1), 42; https://doi.org/10.3390/materproc2023015042 - 09 Nov 2023

Viewed by 469

Abstract

Iron and alumina can be separated from bauxite residue and calcite self-hardened reduced pellets through simultaneous magnetic separation and alkali leaching. Bauxite residue and calcite self-hardened pellets were reduced non-isothermally by hydrogen gas to obtain metallic iron. Thereafter, the fine grounded reduced pellet [...] Read more.

Iron and alumina can be separated from bauxite residue and calcite self-hardened reduced pellets through simultaneous magnetic separation and alkali leaching. Bauxite residue and calcite self-hardened pellets were reduced non-isothermally by hydrogen gas to obtain metallic iron. Thereafter, the fine grounded reduced pellet powder was leached with a simultaneous magnetic stirrer, while two different leaching processes were applied. In a magnetic stirring alkali-leaching process, the simultaneous leaching and magnetic separation by Na₂CO₃ solution was carried out. In another process, the reduced pellets were leached into water with gradual magnetic separation followed by the addition of Na₂CO₃ solution. X-ray diffraction, scanning electron microscopy, X-ray fluorescence, and inductively coupled plasma mass spectroscopy were used to conduct phase analysis, microstructural analysis, compositional analysis, and elemental analysis of the leaching solutions, respectively. It was found that, there was an increase in iron in the magnetic fraction as compared to a nonmagnetic fraction in both the leaching processes; however, the iron recovery is more noticeable in the magnetic alkali leaching process. The recovery of alumina depends upon the amount of mayenite formation during reduction. The greater the amount of mayenite and the lower the amount of gehlenite, the greater the alumina recovery will be. The simultaneous alkali leaching and magnetic separation lead to greater unlocking of the reduced matrix and to greater iron and alumina recovery compared to magnetic water leaching followed by alkaline leaching. Full article

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6 pages, 1283 KiB

Open AccessProceeding Paper

Beneficiation of Eskişehir Beylikova Bastnasite Ore and Rare Earth Elements Recovery

by Gulsah Turker, Tulay Koc Delice, Arda Temizkalb, Ozgun Cem Ozgur and Belma Soydas Sozer

Mater. Proc. 2023, 15(1), 44; https://doi.org/10.3390/materproc2023015044 - 14 Nov 2023

Viewed by 443

Abstract

The unique magnetic, optical, and electrical properties of rare earth elements (REEs) have become essential in modern high technology. Considering the necessity of technology, efficient management and utilization of rare earth resources are of great importance. Even though there are more than 250 [...] Read more.

The unique magnetic, optical, and electrical properties of rare earth elements (REEs) have become essential in modern high technology. Considering the necessity of technology, efficient management and utilization of rare earth resources are of great importance. Even though there are more than 250 rare earth minerals around the world, the number of minerals that can be economically processed does not exceed three. Among these minerals, bastnaesite has a significant impact on scientific advancement and social progress. This project aims to contribute to the establishment of a sustainable supply chain for REE in Türkiye and Europe by conducting research and development activities to leverage the utilization of REEs found in our country. The primary objective of this project is to extract rare earth oxides from complex ore in the Eskişehir Beylikova region, which holds the largest reserve potential discovered in our country, and to refine these metal oxides to produce metals that can be used in magnet manufacturing. The project encompasses five main work packages over three years: project management, ore enrichment, solvent extraction-based purification, utilization of REOs and metals in additive materials, and magnet production. Full article

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7 pages, 1765 KiB

Open AccessProceeding Paper

Impact of Extractant Type and pH on Yttrium Recycling from End of Life Fluorescent Lamp

by Tulay Koc Delice, Gulsah Turker, Huseyin Eren Obuz and Belma Soydas Sozer

Mater. Proc. 2023, 15(1), 45; https://doi.org/10.3390/materproc2023015045 - 14 Nov 2023

Viewed by 446

Abstract

Rare-earth elements (REEs), which are indispensable for high technology and renewable energy, are becoming more significant due to their distinct properties (e.g., catalytic, metallurgical, magnetic, etc.) and their diverse applications in a wide range of contemporary technologies, environmental initiatives, and economic domains. In [...] Read more.

Rare-earth elements (REEs), which are indispensable for high technology and renewable energy, are becoming more significant due to their distinct properties (e.g., catalytic, metallurgical, magnetic, etc.) and their diverse applications in a wide range of contemporary technologies, environmental initiatives, and economic domains. In the pursuit of an environmentally friendly, sustainable, circular approach, recycling and utilizing secondary rare-earth resources as potential reservoirs of REEs may present an alternative to primary mining, addressing future raw material demands. Secondary REE sources include various products such as fluorescent lamps, light-emitting diodes (LEDs), magnets, wind turbines, electric motors, and batteries. Powders used in fluorescent lamps contain approximately 3% phosphorus, and these powders comprise a high ratio of precious REEs such as Y, Eu, La, Ce, and Tb. This study involves the recovery of yttrium from end-of-life fluorescent lamps. The composition of the end-of-life fluorescent lamp was analyzed using X-ray fluorescence (XRF) and X-ray diffraction (XRD) techniques subsequent to grinding. The leaching process was conducted to investigate the effects of leach parameters on the efficiency of the reaction. In the subsequent phase of the study, a solution obtained with the optimum leaching efficiency was subjected to the purification of Y using the solvent extraction (SX) method. The effect of each different extractant and pH values on Y-recovery were investigated for SX process. Yttrium oxide powders were characterized by XRF and ICP(OES) techniques, and high-purity Y₂O₃ powders were obtained with high yield. Full article

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14 pages, 234 KiB

Open AccessProceeding Paper

Sustainability Reporting in the Raw Materials Industry

by Eugenia Filtikaki, Mary Vastardi and Katerina Adam

Mater. Proc. 2023, 15(1), 46; https://doi.org/10.3390/materproc2023015046 - 16 Nov 2023

Viewed by 909

Abstract

The aim of this paper is to study and compare the Global Reporting Initiative (GRI) standard widely used in the Sustainability Reporting of the Raw Material (RM) Industry with the recently emerged European Sustainability Reporting Standards (ESRS). The Non-Financial Reporting Directive (NFRD), 2014, [...] Read more.

The aim of this paper is to study and compare the Global Reporting Initiative (GRI) standard widely used in the Sustainability Reporting of the Raw Material (RM) Industry with the recently emerged European Sustainability Reporting Standards (ESRS). The Non-Financial Reporting Directive (NFRD), 2014, that initially set the requirements for NFR to companies with more than 500 employees, will be replaced by 2024 with the new European Corporate Sustainability Reporting Directive (CSRD) 2023. As of 2024, large undertakings, as well as small and medium-sized undertakings that are public-interest entities, will be required to publish reports on their environmental and social impacts, replacing the NFRD. Within this framework, the present paper aims to review and compare the two standards, GRI and ESRS, given that due to the forthcoming Directive, a significantly higher number of companies, as compared to the entities subjected to NFRD, including large and SME companies of the RM sector, will have to prepare the procedures for the implementation of the new standards. Moreover, it has been reported that EFRAG-GRI organizations have started planning the new standard update. Taking into account the extensive use of the GRI indicators in sustainability reporting, the article highlights both their similarities and differences with the first set of 12 draft ESRS. From this study, it was mainly concluded that the two sustainability reporting standards present several similarities; thus, companies already using GRI are expected to seamlessly adapt to the new standard. Full article

6 pages, 2697 KiB

Open AccessProceeding Paper

Immobilization of Rare Earth Elements and Yttrium (REY) by Iron (Bio)Precipitation in Acid Sulfate Waters from El Bierzo (Spain)

by Blanca Rincón-Tomás, Francisco Javier González, Enrique López-Pamo and Esther Santofimia

Mater. Proc. 2023, 15(1), 47; https://doi.org/10.3390/materproc2023015047 - 16 Nov 2023

Viewed by 386

Abstract

Acid sulfate waters originated from acid rock drainage (ARD), affecting the La Silva stream (El Bierzo, Spain), present anomalously high values of rare earth elements and yttrium (REY). These REY are maintained dissolved along the water stream as sulfate ions forming complexes like [...] Read more.

Acid sulfate waters originated from acid rock drainage (ARD), affecting the La Silva stream (El Bierzo, Spain), present anomalously high values of rare earth elements and yttrium (REY). These REY are maintained dissolved along the water stream as sulfate ions forming complexes like REYSO₄⁺ and REY(SO₄)²⁻. Negatively charged REY complexes seem to have an affinity for iron precipitates found along the La Silva stream and its tributaries since their surface is positively charged at this low pH. The presence of iron-oxidizing bacteria in iron precipitates addresses the possibility of their implication in this REY immobilization and its potential use in (bio)remediation and strategic metal industry applications. Full article

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4 pages, 919 KiB

Open AccessProceeding Paper

Application of the Electro-Electrodialysis Technology in the Copper Mineral Processing Industry: Recovery of Antimony from Mining Tailings and Recycling of the Regenerated Solution Media

by Manuel César Martí-Calatayud, Lorena Hernández-Pérez, Andréa Moura Bernardes, Marco Antônio Siqueira Rodrigues, Gerardo Cifuentes, Gabriel Riveros and Valentín Pérez-Herranz

Mater. Proc. 2023, 15(1), 48; https://doi.org/10.3390/materproc2023015048 - 16 Nov 2023

Viewed by 394

Abstract

In this work, electrodialysis (ED) and electro-electrodialysis (EED) were investigated as technologies for the recovery of Sb from wastes and effluents generated during the pyrometallurgical processing of copper sulfide minerals and the hydrometallurgical treatment of low-copper-content mixed minerals. This work addresses the challenge [...] Read more.

In this work, electrodialysis (ED) and electro-electrodialysis (EED) were investigated as technologies for the recovery of Sb from wastes and effluents generated during the pyrometallurgical processing of copper sulfide minerals and the hydrometallurgical treatment of low-copper-content mixed minerals. This work addresses the challenge of applying electrochemical methods for recovering these valuable materials and recycling highly concentrated acid solutions used in the latter separation stages of the electrorefining process. The electrochemical characterization of the solutions was conducted, and the electrodeposition of Sb and Bi was performed in electrochemical cells. Also, the implementation of membrane processes in the recovery of such materials was investigated. Full article

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7 pages, 223 KiB

Open AccessProceeding Paper

Experience in the Implementation of Risk Management in Occupational Safety and Health and Environmental Issues in Extractive Companies

by Petros Maraboutis, Niki-Iliana Poulimenou and Elena Nikolaou

Mater. Proc. 2023, 15(1), 49; https://doi.org/10.3390/materproc2023015049 - 21 Nov 2023

Viewed by 384

Abstract

Risk management (RM) as a management technique has developed significantly over the past 20 years globally to address risks. RM is often linked to financial, reputational, and quality risks. The purpose of this article is to shed light on how the extractive sector [...] Read more.

Risk management (RM) as a management technique has developed significantly over the past 20 years globally to address risks. RM is often linked to financial, reputational, and quality risks. The purpose of this article is to shed light on how the extractive sector manages environmental and occupational safety and health (OSH) risks through a number of interviews with extractive industries. These interviews were held as part of the European Commission project “Elaboration of Guidelines for Best Risk Management Approaches in the Extractive Sector” in order to investigate synergies between the areas of the environment and OSH for an effective and integrated risk management approach that stimulates improved performance, leading to overall risk reduction. The interviews revealed how the sector addresses risks, which methodologies are most used, and how risk management is applied in each of the main stages of the extractive value chain. According to these interviews, companies seem to actively search to find corrective measures. On an operational level, most extractive companies use a combination of RM tools and custom-made risk management practices, predominantly for internal use and not for licensing. The extractive sector believes that society’s acceptance is a key element to being licensed to operate. Thus, the management of risks from the perspective of providing high OSH standards and, at the same time, achieving the lowest impact on the environment are key to a productive operation. Full article

9 pages, 1975 KiB

Open AccessProceeding Paper

Granulometric, Chemical, and Mineralogical Evaluation of Greek Lignite Bottom Ash for Potential Utilization in Concrete Manufacturing

by Argyro Asvesta, Ioannis Kapageridis, Agapi Vasileiadou, Kyros Koios and Nikolaos Kantiranis

Mater. Proc. 2023, 15(1), 50; https://doi.org/10.3390/materproc2023015050 - 24 Nov 2023

Viewed by 546

Abstract

Coal bottom ash is used globally in various applications in the construction industry to reduce its negative environmental impacts. In this study, the potential utilization of lignite bottom ash from four power plants in Greece in concrete manufacturing was evaluated through granulometric, chemical, [...] Read more.

Coal bottom ash is used globally in various applications in the construction industry to reduce its negative environmental impacts. In this study, the potential utilization of lignite bottom ash from four power plants in Greece in concrete manufacturing was evaluated through granulometric, chemical, and mineralogical analyses. The particle-size distribution of bottom ash obtained from dry sieving resembles that of sand, making bottom ash suitable for replacing fine aggregates in the production of concrete. Its chemical composition, determined with selective point analyses energy dispersive spectroscopy (EDS), reveals high amounts of silica and alumina indicating pozzolanic properties, and high calcium contents suggesting hydraulic/cementitious character. Mineralogical characterization, obtained from powder X-Ray diffraction analyses (XRD), displays the prevalence of amorphous matter, calcite, quartz, aluminosilicate minerals, and portlandite, implying a beneficial pozzolanic and hydraulic activity in concrete manufacturing. Full article

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6 pages, 3003 KiB

Open AccessProceeding Paper

A Review of the Distribution of Critical and Strategic Mineral Raw Materials in the Vein-Type Mineralizations of Vertiskos Unit, Northern Greece

by Christos L. Stergiou, Grigorios Aarne Sakellaris, Vasilios Melfos and Panagiotis Voudouris

Mater. Proc. 2023, 15(1), 51; https://doi.org/10.3390/materproc2023015051 - 24 Nov 2023

Viewed by 319

Abstract

Supply risk and economic importance are the key aspects controlling the metals classified as critical. Several of the critical metals are also classified as rare based on their restricted geological availability. In Europe, numerous mineralizations have been reported as being enriched in critical, [...] Read more.

Supply risk and economic importance are the key aspects controlling the metals classified as critical. Several of the critical metals are also classified as rare based on their restricted geological availability. In Europe, numerous mineralizations have been reported as being enriched in critical, strategic, and rare metals, and could potentially facilitate the production of these metals as by-products. Within this context, this paper reviews the critical and rare metals incorporated in the vein-type mineralization hosted in the Vertiskos unit in Greece. Several Cenozoic polymetallic mineralizations hosted in quartz veins and metamorphic rocks, which are enriched in Cu–As–Pb–Bi–Ag–Au–Te or in Sb-W are being reported in the region. The polymetallic mineral assemblages are characterized by base metal sulfides—Bi-sulfosalts, Bi-sulfotellurides, and tellurides—associated with Au and Ag. On the contrary, Bi-Te mineral phases are lacking or are completely absent from the Sb-W mineralization. The highest critical metals enrichments are reported from Kolchiko and include Bi (995 ppm), Co (320 ppm) and W (844 ppm). Gold is up to 28.3 ppm in Koronouda, while Ag reaches up to 2433 ppm in Laodikino. Full article

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7 pages, 1222 KiB

Open AccessProceeding Paper

Optimizing Geothermal Energy Extraction in CO₂ Plume Geothermal Systems

by Sofianos Panagiotis Fotias, Spyridon Bellas and Vassilis Gaganis

Mater. Proc. 2023, 15(1), 52; https://doi.org/10.3390/materproc2023015052 - 24 Nov 2023

Viewed by 529

Abstract

CPG (CO₂ Plume Geothermal) has recently emerged as a promising technology to combine the extraction of geothermal energy with underground CO₂ storage, thus achieving double positive results. The idea is to inject CO₂ in its supercritical form to create a [...] Read more.

CPG (CO₂ Plume Geothermal) has recently emerged as a promising technology to combine the extraction of geothermal energy with underground CO₂ storage, thus achieving double positive results. The idea is to inject CO₂ in its supercritical form to create a plume and replace the reservoir brine, which is continuously circulated to transfer heat from the reservoir to surface facilities. Apart from the positive aspects of this technology, including the reduced energy to inject and lift the working fluid as well as its enhanced mobility in the reservoir and reduced environmental footprint, there are also negative issues that must be handled by adequately studying the geological field/reservoir and appropriately designing the production system. In this work, we present a finite volume numerical simulation that can study a geothermal reservoir from its geological origin to the dynamic simulation of CO₂ injection and estimate the geothermal energy extraction. It is shown that the system performance is strongly related to the selected schedule, and optimizing it in conjunction with the related cost is of the utmost importance for the Final Investment Decision to be taken and for the viability of such multipurpose projects under a sustainable future. Full article

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8 pages, 2335 KiB

Open AccessProceeding Paper

The Efficient Use of Sulfuric Acid in Bauxite Residue Leaching

by Aikaterini Toli, Dimitrios Kotsanis, Maria Psoma, Danai Marinos, Panagiotis Davris, Efthymios Balomenos and Dimitrios Panias

Mater. Proc. 2023, 15(1), 53; https://doi.org/10.3390/materproc2023015053 - 27 Nov 2023

Viewed by 490

Abstract

Bauxite residue (BR), an alkaline industrial waste, is a major byproduct of the alumina production process known as the Bayer process. The Bayer process generates a byproduct known as bauxite residue (red mud). This residue was leached with sulfuric acid in a pilot [...] Read more.

Bauxite residue (BR), an alkaline industrial waste, is a major byproduct of the alumina production process known as the Bayer process. The Bayer process generates a byproduct known as bauxite residue (red mud). This residue was leached with sulfuric acid in a pilot plant of Mytilineos S.A to recover scandium. Scandium was selectively recovered in pilot-scale experiments using ion exchange. This process generated a raffinate solution containing various dissolved impurities such as aluminum, sodium, calcium, iron, and mainly sulfate ions. The regeneration of the raffinate solution can reduce the cost of the process and minimize the use of H₂SO₄. The potential of raffinate recycling as a technology for reducing the usage of H₂SO₄ in the leaching process was evaluated by neutralizing bauxite residue with a raffinate solution before the leaching step. This study aimed to investigate the feasibility of using a raffinate solution for the neutralization of BR, enabling its reuse and improving the process’s environmental sustainability. The neutralization process decreases the pH value of BR pulp with 50% w/v pulp density from 11 to 6. Experimental investigations were carried out to assess the leaching behavior of bauxite residue compared to neutralized bauxite residue (NBR) using sulfuric acid. The obtained results were compared to evaluate the effectiveness of NBR as a substitute for bauxite residue in the leaching process. The consumption of acid during the leaching of neutralized BR was three times less than the BR leaching. An X-ray diffraction (XRD) analysis of BR and NBR was conducted to determine the mineralogical phases of the materials. The results of the study provide valuable insights into potential ways to reduce the cost of the BR leaching process, while also improving its environmental impact by recycling valuable materials. Full article

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7 pages, 8736 KiB

Open AccessProceeding Paper

Application of Portable Spectroscopic Tools in the Exploration of Manganese Oxide Minerals: Preliminary Results from the Case Study of Drama Mn-Oxide Deposits, Northern Greece

by George Soulamidis, Marjolene Jatteau, Christina Stouraiti, Panagiotis Voudouris, Constantinos Mavrogonatos, Konstantinos Soukis, Cécile Fabre, Marie-Camille Caumon, Jean Cauzid and Alexandre Tarantola

Mater. Proc. 2023, 15(1), 54; https://doi.org/10.3390/materproc2023015054 - 27 Nov 2023

Viewed by 431

Abstract

In situ analysis techniques of ore and drill core samples provide fast results that can be used to facilitate the decision-making process during the geochemical exploration of ore deposits. This study applies the use of two portable devices, pXRF and Laser-Induced Breakdown Spectroscopy [...] Read more.

In situ analysis techniques of ore and drill core samples provide fast results that can be used to facilitate the decision-making process during the geochemical exploration of ore deposits. This study applies the use of two portable devices, pXRF and Laser-Induced Breakdown Spectroscopy (pLIBS), to a small manganese oxide deposit situated in the Rhodope metamorphic complex, Kato Nevrokopi, northern Greece. The study provides an example of exploration of a variety of manganese minerals, including Mn-oxides, Mn-carbonates, and Mn-silicates. It tests the accuracy of mineral identification using these two techniques. The application of pXRF helped in the elemental identification of critical trace metals in certain Mn minerals and showed that there is Ag enrichment in the ore, which is associated with the mineral hetaerolite (ZnMn₂O₄). From the LIBS analysis, it can be seen that Mn minerals with different Mn valences (+2, +3, and +4) display distinct spectra. This observation will be further examined by expanding the sampling pool of the spectra of manganese oxides. It is postulated that the presence of trace elements in Mn minerals may differ according to the valence of the Mn, which in turn affects the LIBS signals of the sample. Full article

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9 pages, 771 KiB

Open AccessProceeding Paper

A Unified Approach to Describing Flow Dynamics in Geothermal Energy Production Systems

by Stefanos Lempesis, Sofianos Panagiotis Fotias and Vassilis Gaganis

Mater. Proc. 2023, 15(1), 55; https://doi.org/10.3390/materproc2023015055 - 30 Nov 2023

Cited by 1 | Viewed by 346

Abstract

Geothermal energy is typically produced by a collection of wells which drain a reservoir. Engineers’ experience and reservoir monitoring data are employed to properly determine the wells in operation and their production rate. However, identifying the optimal well configuration which contributes the most [...] Read more.

Geothermal energy is typically produced by a collection of wells which drain a reservoir. Engineers’ experience and reservoir monitoring data are employed to properly determine the wells in operation and their production rate. However, identifying the optimal well configuration which contributes the most to the geothermal power produced at the system outlet is very complex since the extracted fluid’s energy is attenuated when traveling through the production wells and the surface network toward the delivery point. Undoubtedly, a reliable optimizer focusing on a unified system would greatly improve its management regarding both energy production and sustainability. In this work, a mathematical model is proposed, which fully describes flow in the joined production system, by coupling the reservoir, wellbore and ground pipeline network flow dynamics. The reservoir IPR (inflow performance relationship) curves are combined with the pipeline network’s hydraulic/thermal behavior, to estimate the geothermal fluid’s pressure, flow and temperature at the delivery point. Every design detail, such as the well geometry, subsurface heat loss and pressure/heat loss along the ground pipeline network, is accounted for. Subsequently, an optimizer identifies the choking that needs to be imposed at each wellhead, so that the geothermal fluids produced account for the minimum mass rate for a given heat load, thus contributing to the sustainability of the geothermal system. The model can be calibrated using history matching to further improve the estimation accuracy. Optimal conditions can be recalculated every time a change takes place in the subsurface system, the surface network or the production constraints. Full article

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3 pages, 373 KiB

Open AccessProceeding Paper

Energy Transition Metals: Future Demand and Low-Carbon Processing Technologies

by Konstantinos Komnitsas, Ilias Lazos and Toni Eerola

Mater. Proc. 2023, 15(1), 56; https://doi.org/10.3390/materproc2023015056 - 13 Dec 2023

Viewed by 641

Abstract

This paper discusses the importance of the energy transition metals Ni, Co and Li in building Europe’s clean technology value chains and meeting the 2050 climate-neutrality goal. Some emerging metal extraction technologies, investigated in the framework of the Horizon Europe projects ENICON and [...] Read more.

This paper discusses the importance of the energy transition metals Ni, Co and Li in building Europe’s clean technology value chains and meeting the 2050 climate-neutrality goal. Some emerging metal extraction technologies, investigated in the framework of the Horizon Europe projects ENICON and EXCEED, in order to decrease the carbon footprint of the production of energy transition metals, are also discussed. Full article

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12 pages, 32012 KiB

Open AccessProceeding Paper

Recovery of Stainless Steel from End-of-Use Dishwashers

by Eirini Evangelou, Georgios N. Anastassakis, Spyridon-Dionysios Karamoutsos and Athanasios Stergiou

Mater. Proc. 2023, 15(1), 57; https://doi.org/10.3390/materproc2023015057 - 14 Dec 2023

Viewed by 343

Abstract

Wastes of Electrical and Electronic Equipment (WEEE) include a variety of products, from house appliances to spacecraft equipment, turning them into a significant source of secondary raw materials. Stainless steel is one of the most useful and valuable products of WEEE. Large quantities [...] Read more.

Wastes of Electrical and Electronic Equipment (WEEE) include a variety of products, from house appliances to spacecraft equipment, turning them into a significant source of secondary raw materials. Stainless steel is one of the most useful and valuable products of WEEE. Large quantities of stainless steel can be recovered from dishwashers. In this research project, the preparation of the samples includes the separation of their components, according to the following successive procedure: the dishwashers are processed through a magnetic separator to hold the magnetic ferrous pieces, an eddy current separator to separate the non-ferrous metals and an induction sorting sensor to detect and separate the remaining metallic fractions. From this procedure, two outgoing streams are produced: the stainless steel stream with some impurities and the impurity stream. Thereinafter, the stainless steel stream passes through a high intensity magnetic separator in order to eliminate the contained impurities. The result of this high-intensity magnetic separation is a magnetic stream containing the stainless steel pieces and a non-magnetic stream which contains the impurities. The final step of this procedure is hand sorting, so that any remaining impurities in the magnetic stream are removed. Full article

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9 pages, 2553 KiB

Open AccessProceeding Paper

Isothermal Pre-Reduction Behavior of Nchwaning Manganese Ore in H₂ Atmosphere

by Alok Sarkar, Trygve Lindahl Schanche and Jafar Safarian

Mater. Proc. 2023, 15(1), 58; https://doi.org/10.3390/materproc2023015058 - 15 Dec 2023

Viewed by 594

Abstract

The application of H₂ to pre-reduce manganese ores is a sustainable approach to performing decarbonization in the ferroalloy industry. The process has been extensively studied and tested in a lab-to-pilot scale in the HAlMan EU project. This work presents the results of [...] Read more.

The application of H₂ to pre-reduce manganese ores is a sustainable approach to performing decarbonization in the ferroalloy industry. The process has been extensively studied and tested in a lab-to-pilot scale in the HAlMan EU project. This work presents the results of an experimental study that was conducted in a lab-scale vertical thermogravimetric furnace for the pre-reduction of a manganese ore by H₂ under isothermal conditions at 500 °C, 600 °C, 700 °C, and 800 °C. The ore and reduced samples were characterized by XRF, XRD, BET and SEM techniques to outline the H₂ reduction behavior of the ore from mineralogical, microstructural, and chemical points of view. The rate and extent of reduction were studied using the continuous mass changes during the reduction. It was found that the pre-reduction at a temperature of 700 °C and 800 °C yields metallic iron formation from Fe₂O₃ and MnO formation from MnO₂/Mn₂O₃. The pre-reduction at lower temperatures did not show a complete reduction in Fe and MnO. The pore structure of the ore was affected by the pre-reduction temperature, and a significant porosity evolution was observed. Full article

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7 pages, 249 KiB

Open AccessProceeding Paper

Exploring Barriers to the Implementation of Circularity Processes for Batteries

by Vasileios Rizos and Patricia Urban

Mater. Proc. 2023, 15(1), 59; https://doi.org/10.3390/materproc2023015059 - 15 Dec 2023

Viewed by 442

Abstract

The batteries sector is expected to play a key role in the energy transition and will need to cope with soaring material demand in the future. Implementing circularity approaches for batteries that enter the EU market is considered to be among the key [...] Read more.

The batteries sector is expected to play a key role in the energy transition and will need to cope with soaring material demand in the future. Implementing circularity approaches for batteries that enter the EU market is considered to be among the key options for mitigating the impacts of increased resource use, but also for securing future access to raw materials needed for decarbonization technologies. Using a multi-case study method, this paper aims to identify key challenges that hinder the adoption of circularity and resource efficiency practices by companies in the battery sector. The analysis is based on qualitative data collected from a sample of 10 companies. To support the categorization of data, a conceptual framework of existing barriers faced by businesses implementing circularity models is developed through a literature review. This paper concludes by identifying areas where EU policy intervention is needed. Full article

6 pages, 1946 KiB

Open AccessProceeding Paper

Recovery of Copper and Zinc from the Ash of Incinerated Municipal Waste

by Ragnhild Elise Dirdal, Aslak Roalkvam Skåra, Eirik Nøst Nedkvitne, Jon Petter Omtvedt and Dag Øistein Eriksen

Mater. Proc. 2023, 15(1), 60; https://doi.org/10.3390/materproc2023015060 - 15 Dec 2023

Viewed by 387

Abstract

We tested some possible processes for using ashes from incinerators, both fly and bottom ash, and included older processes, like the Schnabel process, in our assessment. The possibilities for selective leaching with ammonia and ammonium carbonate are utilized, as well as ammonia recycling. [...] Read more.

We tested some possible processes for using ashes from incinerators, both fly and bottom ash, and included older processes, like the Schnabel process, in our assessment. The possibilities for selective leaching with ammonia and ammonium carbonate are utilized, as well as ammonia recycling. Fly ash and bottom ash may be treated similarly but with some specific differences. Our conclusion is that recovery from incinerated municipal waste ash is an economical and viable source of copper and zinc. Such a process will also reduce the amount of waste to handle and make it more chemically stable due to the alkalinity of the residue. Full article

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7282 KiB

Open AccessProceeding Paper

Contribution to the Optimization of the Smelting Reduction of Nickeliferous Laterites, Based on the Recent Industrial Experience

by Charalabos Zografidis and Konstantinos Betsis

Mater. Proc. 2023, 15(1), 61; https://doi.org/10.3390/materproc2023015061 - 19 Dec 2023

Viewed by 261

Abstract

The Greek ferronickel industry faces the challenge of restructuring and reoperation in the future, given that privatization is in progress, including the acquisition of the company’s assets for a joint venture enterprise. Within this framework, the current paper aims to contribute to the [...] Read more.

The Greek ferronickel industry faces the challenge of restructuring and reoperation in the future, given that privatization is in progress, including the acquisition of the company’s assets for a joint venture enterprise. Within this framework, the current paper aims to contribute to the discussion about developing a new management strategy for the optimization of the pyrometallurgical process, focusing on the critical step of smelting reduction. Based mainly on industrial experience, factors which critically affect the safety and cost-effectiveness of smelting reduction are detected and presented, also by means of case studies, being classified as follows: (i) optimal raw materials’ feed management, including laterite ores (domestic or not), solid fuels and electrode paste; (ii) focus on preventive maintenance management. Substantial increase in the facilities’ operational index and cost saving is obtained; (iii) modern human resources management strategy, enhancing evaluation indicators’ use, education culture, process standardization and tacit—explicit knowledge management. Their economic footprint is discussed. Full article

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7 pages, 1307 KiB

Open AccessProceeding Paper

Li Extraction from a-Spodumene Concentrate via Carbonizing Calcination

by Katerina Maliachova, Nikolaos Doukas, Danai Tsakiri, Michail Samouhos, Lefkothea Sakellariou, Iliana Douni, Maria Taxiarchou and Ioannis Paspaliaris

Mater. Proc. 2023, 15(1), 62; https://doi.org/10.3390/materproc2023015062 - 21 Dec 2023

Viewed by 828

Abstract

The conventional lithium extraction method involves the calcination of a-spodumene at 1050 °C so that it can be converted to the more-reactive b-spodumene and then a sulfuric acid roasting step at 250 °C. Lithium is finally extracted via leaching with water. This method [...] Read more.

The conventional lithium extraction method involves the calcination of a-spodumene at 1050 °C so that it can be converted to the more-reactive b-spodumene and then a sulfuric acid roasting step at 250 °C. Lithium is finally extracted via leaching with water. This method is energy-intensive, leading to high capital and operational costs. In this study, the direct calcination of a-spodumene with the use of sodium carbonate and calcium oxide was examined, aiming to significantly reduce the calcination temperature and completely omit the sulfuric acid roasting step, thereby radically redesigning the lithium extraction process. The calcination product was then leached with different leaching agents, such as water and sulfuric acid, and at different temperatures. The efficiency of the additives was evaluated through the results of lithium extraction achieved during the leaching step. Different leaching agents and temperatures were investigated. The maximum lithium extraction achieved was 96%, obtained after calcination using a sodium carbonate/spodumene mixture and leaching with sulfuric acid at 90 °C. High lithium extractions, up to 83%, can also be achieved under the same calcination conditions and after leaching with sulfuric acid at lower temperatures, such as 40 °C, and for shorter leaching times. Full article

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5 pages, 908 KiB

Open AccessProceeding Paper

Possibilities and Limitations of the Use of Hydrogen in Different Metallurgical Sectors

by Casper van der Eijk, Halvor Dalaker and Jafar Safarian

Mater. Proc. 2023, 15(1), 63; https://doi.org/10.3390/materproc2023015063 - 21 Dec 2023

Viewed by 451

Abstract

Hydrogen is increasingly being recognized as a crucial element in reducing carbon emissions in the metallurgical industry. Its use in the steel sector is gaining momentum through various initiatives at high TRL levels. Moreover, hydrogen shows promise in other metal production processes as [...] Read more.

Hydrogen is increasingly being recognized as a crucial element in reducing carbon emissions in the metallurgical industry. Its use in the steel sector is gaining momentum through various initiatives at high TRL levels. Moreover, hydrogen shows promise in other metal production processes as well. One application involves utilizing hydrogen for effective selective reduction copper from copper slags with a low amount of iron being reduced. Hydrogen can also be employed in the pre-reduction of manganese ore, leading to the carbon-free production of manganese metal through aluminothermic reactions. Additionally, hydrogen can be used in the processing of bauxite residue, where iron is partially or completely reduced to separate an iron-rich fraction, allowing for alumina recovery via leaching. Full article

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4 pages, 715 KiB

Open AccessProceeding Paper

Structural and Electrochemical Characterization of Natural Manganese Oxides for Energy Storage Applications

by George Soulamidis, Christina Stouraiti, Maria Kourmousi, Panagiotis Tzevelekidis, Eleni Charalampous and Christiana A. Mitsopoulou

Mater. Proc. 2023, 15(1), 64; https://doi.org/10.3390/materproc2023015064 - 25 Dec 2023

Viewed by 377

Abstract

Manganese oxide minerals have a remarkable range of applications. This investigation delves into their potential utility in energy storage, particularly as supercapacitors. The study centers on natural manganese oxides sourced from the Drama region (Greece), evaluating their electrochemical promise and devising strategies for [...] Read more.

Manganese oxide minerals have a remarkable range of applications. This investigation delves into their potential utility in energy storage, particularly as supercapacitors. The study centers on natural manganese oxides sourced from the Drama region (Greece), evaluating their electrochemical promise and devising strategies for addressing the remediation of mining waste sites. Samples were collected from abandoned mining sites at Kato Nevrokopi area, Drama region. Techniques such as X-ray diffraction (XRD) were employed to probe the structural characteristics of the minerals. Electrochemical studies involved the preparation of electrodes using natural and heat-treated nsutite (hausmannite). Then, the designed electrodes were subjected to cyclic voltammetry tests and charge-discharge measurements. Results showed superior electrochemical performance for the hausmannite-based electrode due to its greater structural homogeneity. Full article

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7 pages, 414 KiB

Open AccessProceeding Paper

Multi-Risk Assessment in Post-Mining Lignite Areas

by Dafni M. Nalmpant-Sarikaki, Alexandros I. Theocharis, Nikolaos C. Koukouzas, Andreas G. Benardos and Ioannis E. Zevgolis

Mater. Proc. 2023, 15(1), 65; https://doi.org/10.3390/materproc2023015065 - 25 Dec 2023

Viewed by 281

Abstract

As Europe addresses decarbonization, huge coal mining areas shall be reclaimed and appropriately valorized, creating the post-mining areas. This work assesses their resilience and safety by methodologically addressing multi-hazards threatening closed and abandoned mines. The current work modifies an indicator-based semi-quantitative multi-hazard method [...] Read more.

As Europe addresses decarbonization, huge coal mining areas shall be reclaimed and appropriately valorized, creating the post-mining areas. This work assesses their resilience and safety by methodologically addressing multi-hazards threatening closed and abandoned mines. The current work modifies an indicator-based semi-quantitative multi-hazard method towards post-mining risk assessment, described as the (1) identification of the hazards, (2) assessment of the interactions, and (3) quantification of the level of interactions. The methodology can appropriately quantify the multi-hazard severity for various scenarios. However, it has limitations, not considering appropriately the hazards’ sequence and missing an objective criterion for scenario comparison. Full article

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6 pages, 2870 KiB

Open AccessProceeding Paper

Geochemical and Limnological Characterization of the Corta Atalaya Pit Lake (Riotinto Mines, Spain)

by Esther Santofimia, Blanca Rincón-Tomás, Enrique López-Pamo, Francisco Javier González and Ricardo Amils

Mater. Proc. 2023, 15(1), 66; https://doi.org/10.3390/materproc2023015066 - 25 Dec 2023

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Abstract

This study examines some relevant limnological and hydrogeochemical characteristics of the most emblematic pit lake of the Iberian Pyrite Belt (IPB). Corta Atalaya (CA) open pit mine is known for its large size and for being one of the most important exploitations of [...] Read more.

This study examines some relevant limnological and hydrogeochemical characteristics of the most emblematic pit lake of the Iberian Pyrite Belt (IPB). Corta Atalaya (CA) open pit mine is known for its large size and for being one of the most important exploitations of copper in Europe. Despite its historical importance, little is known about the lake formed in this open pit. During this study, the pit lake presented a surface area of 16 ha, a maximum depth of 106 m, and a 5.8 hm³ volume of acid and metal-enriched water. CA pit lake shows permanent chemical stratification (meromictic lake), where three layers with different density and chemical composition can be differentiated: (i) a superficial layer of 5 ± 2 m water depth, with electric conductivity (EC) between 5.4–6.64 mS/cm, and oxygenated and Fe(III)-rich mixolimnion; (ii) an intermediate layer (between 5–30 m, chemocline), exhibiting strong vertical changes in parameters such as temperature (T) and EC, which show an increase with depth; and (iii) a thick bottom layer from 30 m to 106 m depth, with anoxic, elevated EC (47 mS/cm) and T (32 °C) values, and a concentration of Fe as Fe(II) (monimolimnion).The characterization of the water column is essential to know the potential sources of strategic and critical raw materials, and to evaluate their possible recuperation, thereby activating a circular economy. Full article

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10 pages, 4958 KiB

Open AccessProceeding Paper

High-Performance Solid-Phase Extraction Chromatography for Recycling of NdFeB Magnet Waste

by Tiaan Punt, Kerstin Forsberg and Michael Svärd

Mater. Proc. 2023, 15(1), 67; https://doi.org/10.3390/materproc2023015067 - 25 Dec 2023

Viewed by 284

Abstract

The increasing use of rare-earth elements (REEs) in renewable technologies such as electric vehicles and wind turbines is driving a rapid rise in their economic importance. This work investigated the separation of REEs (Nd, Pr, Sm, and Dy) from NdFeB magnets using high-performance [...] Read more.

The increasing use of rare-earth elements (REEs) in renewable technologies such as electric vehicles and wind turbines is driving a rapid rise in their economic importance. This work investigated the separation of REEs (Nd, Pr, Sm, and Dy) from NdFeB magnets using high-performance solid-phase extraction chromatography. More than 99% of the REEs were extracted from an Fe-rich sulfate-based leach liquor using a three counter-current stage solvent extraction of 34.7 vol.% and O/A 1.5. The REE-loaded H₂SO₄ strip solution was separated into a high-purity Nd and Pr fraction from separate Sm and Dy fractions in a single stage using a D2EHPA-impregnated column and H₂SO₄ gradient elution. Full article

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9 pages, 1771 KiB

Open AccessProceeding Paper

Investigation of Recycling Behavior of Lithium Iron Phosphate Batteries with Different Thermal Pre-Treatments

by Hüseyin Eren Obuz, Firat Tekmanli, Luka Nils Mettke, Marius Müller and Bengi Yagmurlu

Mater. Proc. 2023, 15(1), 68; https://doi.org/10.3390/materproc2023015068 - 26 Dec 2023

Viewed by 562

Abstract

Lithium iron phosphate (LFP) batteries are becoming a growing trend as a consequence of EU regulations and their advantages over nickel manganese cobalt (NMC) batteries. The use of LFP batteries is expected to increase considerably globally, creating an enormous waste problem. Battery recycling [...] Read more.

Lithium iron phosphate (LFP) batteries are becoming a growing trend as a consequence of EU regulations and their advantages over nickel manganese cobalt (NMC) batteries. The use of LFP batteries is expected to increase considerably globally, creating an enormous waste problem. Battery recycling is emphasized in the EU’s battery laws, especially for lithium. Proper recycling of LFP batteries reduces environmental damage and supports the circular economy. Graphite and lithium are acknowledged as essential raw minerals. Recycling LFP batteries can be accomplished using pyrometallurgical and hydrometallurgical techniques. This study investigates the impact of thermal pre-treatments on flotation and leaching to produce an efficient recycling process. Full article

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7 pages, 3034 KiB

Open AccessProceeding Paper

Electric Arc Furnace Dust Vitrification via Soda Lime Recycled Glass

by Andronikos Maris, Dimitra Ioannidou, Ilias Sammas, Stavros Deligiannis and Petros E. Tsakiridis

Mater. Proc. 2023, 15(1), 69; https://doi.org/10.3390/materproc2023015069 - 27 Dec 2023

Viewed by 330

Abstract

The present research work focuses on the characterization and leachability evaluation of electric arc furnace dust (EAFD) and its vitreous outgrowths produced during vitrification with soda lime recycled glass (SLRG). EAFD is a hazardous industrial waste generated in the collection of particulate material [...] Read more.

The present research work focuses on the characterization and leachability evaluation of electric arc furnace dust (EAFD) and its vitreous outgrowths produced during vitrification with soda lime recycled glass (SLRG). EAFD is a hazardous industrial waste generated in the collection of particulate material during the steelmaking process via an electric arc furnace. Glasses of various syntheses were obtained during EAFD vitrification with various amounts of silica scrap (50, 60 and 70 wt%). The characterization of the as-received dust was carried out by using granulometry analysis, chemical analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM), in conjunction with Energy Dispersive X-ray Spectroscopy (EDS). The produced glasses during vitrification were studied by means of chemical and mineralogical analysis, whereas their microstructure in polished sections was examined by SEM/EDS. Their behavior during leaching was determined by the EN 12457-2 compliance leaching test and according to the results, the trace elements detected in the leachates were well below the corresponding regulatory limits. Full article

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6 pages, 1163 KiB

Open AccessProceeding Paper

Evolution of Alluvial Gold Mining Technologies

by Spyridon Mathioudakis, George Xiroudakis, Evangelos Petrakis and Emmanouil Manoutsoglou

Mater. Proc. 2023, 15(1), 70; https://doi.org/10.3390/materproc2023015070 - 28 Dec 2023

Viewed by 543

Abstract

This work provides historical information and examines changes in the methods and equipment used in gold recovery and processing operations. Alluvial gold recovery methods, mainly based on gravity separation combined with mercury (amalgamation), have been applied since the early days of mining. Historically, [...] Read more.

This work provides historical information and examines changes in the methods and equipment used in gold recovery and processing operations. Alluvial gold recovery methods, mainly based on gravity separation combined with mercury (amalgamation), have been applied since the early days of mining. Historically, mining gold from the riverbeds was first implemented in Ancient Anatolia (also called “Asia Minor”) and Ancient Greece. As a first attempt to recover gold, the traditional immersion of sheepskin in river water to trap alluvial gold was developed. This technique has been considered a milestone in the famous myth of the Golden Fleece. Since then, gold extraction and processing technologies have evolved. In this respect, Emperor Augustus developed hydraulic gold mining during the period of the Roman Empire. Subsequently, the innovative machines of Georgius Bauer (Agricola) were widely used during the Renaissance, while Spanish colonialists in America improved their techniques by observing the efficient methods of the natives. Finally, the “American Gold Rush” era was perhaps the most crucial period of the alluvial gold mining process. It took place along the rivers of America during the 19th and 20th centuries. Today, in the technologically advanced society, various gold mining machines, including spiral and jig concentrators, provide higher production rates and less environmental harm. Full article

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8 pages, 2032 KiB

Open AccessProceeding Paper

Investigation of Industrial Residues and Waste Materials to Expand the Raw Material Base for the Production of Lightweight Aggregates

by Jacob Fenner, Andrej Zeller, Steffen Liebezeit, Manuela Knorr, Alexander Schnell, Luka Mettke and Daniel Goldmann

Mater. Proc. 2023, 15(1), 71; https://doi.org/10.3390/materproc2023015071 - 03 Jan 2024

Viewed by 298

Abstract

More than 218 million tonnes of mineral construction waste are produced in Germany every year. In view of the shortage of domestic raw materials and an increasing demand for lightweight aggregates and gypsum, it is important to find alternative sources of raw materials [...] Read more.

More than 218 million tonnes of mineral construction waste are produced in Germany every year. In view of the shortage of domestic raw materials and an increasing demand for lightweight aggregates and gypsum, it is important to find alternative sources of raw materials for the production of light aggregates. The main focus of our investigations is on construction and demolition waste and industrial by-products, which have so far only been used at a low level. Chemical analyses can be used to classify potential substances in the ternary diagram according to RILEY and to examine their basic suitability. However, the results show that the suitability of a raw material for the production of lightweight aggregates cannot be determined solely on the basis of the classification in the ternary diagram. Experimental investigations are necessary in any case. From the range of residual and waste materials investigated, the rhyolite fractions showed the best bloating properties. Without the addition of bloating agents, bloating values of 1.4 can be achieved. The addition of iron slurry to a reduction in the bloating temperature by about 100 °C, however, is associated with a slight reduction in the bloating value. With our investigations, we were able to show that an expansion of the raw material base for the production of lightweight aggregates is also possible beyond the use of classic, heterogeneous building rubble containing bricks. Full article

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8 pages, 1849 KiB

Open AccessProceeding Paper

Effect of Freeze–Thaw Cycles on the Flexural Strength of Greek Natural Stones

by Konstantinos Laskaridis, Angeliki Arapakou, Michael Patronis, Christos Papatrechas and Ioannis Kouseris

Mater. Proc. 2023, 15(1), 72; https://doi.org/10.3390/materproc2023015072 - 05 Jan 2024

Viewed by 795

Abstract

The purpose of this study is to explore the potential influence of cyclic freezing–thawing on the flexural strength of Greek natural stones that are extensively utilized for construction or decoration purposes. Such testing approaches are an indispensable part of the stone selection criteria [...] Read more.

The purpose of this study is to explore the potential influence of cyclic freezing–thawing on the flexural strength of Greek natural stones that are extensively utilized for construction or decoration purposes. Such testing approaches are an indispensable part of the stone selection criteria due to their ability to assess the stone’s durability. It is especially crucial in locations where exposure to freeze–thaw cycles is common. For this study, samples from various types of stones, including limestones, calcite and dolomite marble, cipollino marble, schists, and mylonites, were examined to assess their flexural strength under concentrated loads and their associated values after freeze–thaw cycles in compliance with European standards (EN). The results show that stones of the same type have comparable flexural strength behaviour. Only in a few cases were significant increases or decreases in strength observed. Specific stones demonstrated a substantial reduction in their flexural strength when exposed to freeze–thaw cycling despite their initially calculated high values without having undergone the frost durability test. Full article

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9 pages, 3035 KiB

Open AccessProceeding Paper

Prediction of Hydrate Dissociation Conditions in Natural/Acid/Flue Gas Streams in the Presence and Absence of Inhibitors

by Ismail Ismail and Vassilis Gaganis

Mater. Proc. 2023, 15(1), 73; https://doi.org/10.3390/materproc2023015073 - 08 Jan 2024

Viewed by 364

Abstract

Accurate predictions of hydrate dissociation conditions are of paramount importance for optimizing mitigation strategies and preventing hydrate formation in oil and gas operations. These predictions are crucial for selecting appropriate thermodynamic inhibitors, reducing operating costs, and minimizing environmental impact. Moreover, they facilitate the [...] Read more.

Accurate predictions of hydrate dissociation conditions are of paramount importance for optimizing mitigation strategies and preventing hydrate formation in oil and gas operations. These predictions are crucial for selecting appropriate thermodynamic inhibitors, reducing operating costs, and minimizing environmental impact. Moreover, they facilitate the practical application of innovative hydrate technologies such as energy storage, gas separation, and carbon capture. To address this need, various commercial PVT software packages, such as MultiFlash, HydraFLASH, CSMGem, and CSMHyd, are commonly used. However, these packages employ different computational approaches, including hydrate modeling, equations of state (EoS), and phase behavior representation, which can influence their prediction capabilities. To assess their accuracy, we conducted an evaluation using a comprehensive database of 400 experimental dissociation pressure data points from both uninhibited and inhibited hydrate former systems. Through our evaluation, we identified the unique strengths and weaknesses of each software package, providing valuable guidance for industry practitioners and researchers who aim to accurately predict hydrate stability conditions, enabling them to implement effective mitigation strategies and exploit technological solutions. Full article

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10 pages, 1184 KiB

Open AccessProceeding Paper

Well Control Strategies for Effective CO₂ Subsurface Storage: Optimization and Policies

by Ismail Ismail and Vassilis Gaganis

Mater. Proc. 2023, 15(1), 74; https://doi.org/10.3390/materproc2023015074 - 08 Jan 2024

Viewed by 475

Abstract

To combat the detrimental impacts of climate change and meet the obligations outlined in the 2015 Paris Agreement, Carbon Capture, Utilization, and Storage (CCUS) has emerged as a crucial technology with significant potential for achieving climate targets. CCUS involves the capture, storage, and [...] Read more.

To combat the detrimental impacts of climate change and meet the obligations outlined in the 2015 Paris Agreement, Carbon Capture, Utilization, and Storage (CCUS) has emerged as a crucial technology with significant potential for achieving climate targets. CCUS involves the capture, storage, and utilization of carbon dioxide (CO₂) emissions from existing energy infrastructure, hard-to-abate industries, or directly from the atmosphere, presenting a promising solution for emission reduction. However, fully harnessing the benefits of carbon storage requires the development of technically robust, safe, and cost-effective well control strategies that align with fundamental subsurface policies. This study aims to offer a comprehensive reference guide for carbon storage applications by reviewing relevant research in the field and establishing key subsurface storage policies for carbon storage in saline aquifer formation along with their practical implementation in carbon storage development plans. Additionally, we explore the utilization of optimization techniques employed thus far in the development of effective well control strategies in saline aquifers, presenting mathematical tools utilized and the achieved results. Full article

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6 pages, 1181 KiB

Open AccessProceeding Paper

Mineral Exploration at the Kimmeria Fe-Cu Skarn Deposit, N. Greece: Reassessment and New Perspectives Focusing on the CRMs

by Michalis Fitros, Constantinos Mavrogonatos, Marianthi Anastasatou, Adamantia Chatziapostolou, Konstantinos Laskaridis, Petros Karmis, Magdalini Angeli, Dimitrios Tsouvalas, Alexandros Liakopoulos, Dimitrios Tarenidis and Vasiliki Angelatou

Mater. Proc. 2023, 15(1), 75; https://doi.org/10.3390/materproc2023015075 - 12 Jan 2024

Viewed by 427

Abstract

Following the worldwide increasing demand for Critical Raw Materials (CRMs), the Hellenic Geological Survey (HSGME) implemented a national project focused on the re-evaluation of certain Public Mining Areas in Greece. In this framework, exploration activities, including geological mapping, and mineralogical, geochemical, and geophysical [...] Read more.

Following the worldwide increasing demand for Critical Raw Materials (CRMs), the Hellenic Geological Survey (HSGME) implemented a national project focused on the re-evaluation of certain Public Mining Areas in Greece. In this framework, exploration activities, including geological mapping, and mineralogical, geochemical, and geophysical studies, revealed significant mineralization targets which possibly host elevated contents of certain CRMs in the Kimmeria Fe skarn deposit. The mineralization is related to the contact metamorphic aureole of the Oligocene Xanthi pluton. Various skarn minerals form the following paragenetic zones in order of decreasing temperature: (i) garnet–wollastonite, (ii) garnet–clinopyroxene, (iii) garnet–epidote, and (iv) vesuvianite–scapolite. The skarn deposit consists of magnetite-rich ore occurring along with sulfides (chalcopyrite, pyrite, bismuthinite, and molybdenite), scheelite, minor sulfosalts (aikinite, wittichenite, and cubanite) and native elements (Au and Bi). Bulk-rock geochemical analyses yielded significant values, as follows: Fe₂O₃, up to 58 wt%; Cu, up to 6.6 wt%; Bi, up to 1100 ppm; W, up to 670 ppm; V, up to 200 ppm; Mo, up to 200 ppm; and Au, up to 2.1 g/t. Soil and stream sediment geochemistry reveals spatial and linear trends for certain groups of associated elements (i.e., Fe₂O₃-Cu-Bi-W and Mo-W-Zn). These trends reflect the surficial distribution of mineralized zones and imply the existence of partially unexposed mineralization in the western part of the study area, a fact also supported by geophysical evidence. A preliminary drilling project has been proposed to evaluate the qualitative characteristics of the deeper parts of the mineralization, investigate buried ore zones in the western part, and overall, reassess the economic potential of the deposit. Full article

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5 pages, 1022 KiB

Open AccessProceeding Paper

Biotechnological Recycling and Recovery of Metals from Waste Printed Circuit Boards and Spent Li-Ion Batteries—Selected Results from the ERAMIN EU BaCLEM Project

by Sandeep Panda, Ata Akcil, Stoyan Gaydardzhiev, Eric D. van Hullebusch, Mehmet Gönen and Seydou Dembele

Mater. Proc. 2023, 15(1), 76; https://doi.org/10.3390/materproc2023015076 - 16 Jan 2024

Viewed by 437

Abstract

This project investigated metal recovery from waste printed circuit boards (WPCBs) and spent lithium-ion batteries (LiBs) using pure and mixed-culture acidophilic microorganisms. It was shown that the mixed culture could recover 80% of Li and 98% of Co from a representative LiB sample [...] Read more.

This project investigated metal recovery from waste printed circuit boards (WPCBs) and spent lithium-ion batteries (LiBs) using pure and mixed-culture acidophilic microorganisms. It was shown that the mixed culture could recover 80% of Li and 98% of Co from a representative LiB sample under shaken flask conditions while using a single acidophilic microorganism in a two-step bioleaching step, 82% of Cu and 100% of Ni could be recovered from PCBs. The removal of iron from the bioleaching solution reached 100% using NaOH. Full article

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6 pages, 1134 KiB

Open AccessProceeding Paper

Recovery of Critical Raw Materials from Abandoned Mine Wastes: Some Potential Case Studies in Northwest Italy

by Gabriele Baldassarre, Adriano Fiorucci and Paola Marini

Mater. Proc. 2023, 15(1), 77; https://doi.org/10.3390/materproc2023015077 - 05 Feb 2024

Viewed by 277

Abstract

Critical and Strategic Raw Materials European Union’s policies are targeting the production of fundamental raw materials from internal sources, fostering the recovery of relevant quantities of materials from the existing mining facilities in Europe. Northwest Italy was an important mining area until the [...] Read more.

Critical and Strategic Raw Materials European Union’s policies are targeting the production of fundamental raw materials from internal sources, fostering the recovery of relevant quantities of materials from the existing mining facilities in Europe. Northwest Italy was an important mining area until the mid-1900s, as reported by the Italian inventory of closed mining waste storage facilities, referring to 92 mining waste facilities. Three sites were chosen to better define their historical and bibliographical framework. The selected sites comprise the Traversella Mine (Piedmont), Libiola Mine (Liguria) and Herin Mine (Aosta Valley). Currently, there are relevant amounts of abandoned mining waste in the surrounding areas of these closed mines. The potential recovery of the residual valuable fraction of these materials could be crucial for both critical raw materials’ recovery and environmental valorization of the involved territories. Full article

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7 pages, 724 KiB

Open AccessProceeding Paper

CO₂ Utilisation in Added-Value Construction Products from Magnesia Production

by Guilherme M. D. M. Rubio and David Konlechner

Mater. Proc. 2023, 15(1), 78; https://doi.org/10.3390/materproc2023015078 - 05 Feb 2024

Viewed by 347

Abstract

In this paper, we propose a solution for the enrichment of CO₂-containing streams from the production of magnesium oxide based on an oxyfuel process for further utilization as raw materials in the carbonation of building materials. A simulation of a specific [...] Read more.

In this paper, we propose a solution for the enrichment of CO₂-containing streams from the production of magnesium oxide based on an oxyfuel process for further utilization as raw materials in the carbonation of building materials. A simulation of a specific case in the magnesia industry was investigated and the results were analyzed. Full article

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7 pages, 1760 KiB

Open AccessProceeding Paper

Onsite Characterisation of Composite Laterite Blocks by Using Novel Sensing Technologies—An Experimental Approach

by Basileios Deligiorgis, Declan Vogt, Ferenc Mádai and Michael Galetakis

Mater. Proc. 2023, 15(1), 79; https://doi.org/10.3390/materproc2023015079 - 05 Feb 2024

Viewed by 293

Abstract

Testing on physical equivalents of mining blocks under controlled conditions offers reduced research costs and improved experiment repeatability. In this study, specimens consisting of ore, waste aggregates, and cement as binder are fabricated to resemble the mineralogical composition and physical properties of real [...] Read more.

Testing on physical equivalents of mining blocks under controlled conditions offers reduced research costs and improved experiment repeatability. In this study, specimens consisting of ore, waste aggregates, and cement as binder are fabricated to resemble the mineralogical composition and physical properties of real mining blocks of a ferro-nickel lateritic deposit. These specimens were measured using sensors on robotic scanners for onsite characterisation, including pLIBS, pXRF, a magnetic susceptibility sensor, and a laser profilometer. Results showed that these analogue rocks could retain the properties of the source rocks, but also that the intensity of the recorded signal is strongly affected by specimens’ water content, porosity, and surface roughness. Full article

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6 pages, 188 KiB

Open AccessProceeding Paper

Fuelling the Foundation Industries: Discovering the Hidden Value of Mineral Waste in the UK

by Clive Mitchell, Tom Bide and Evi Petavratzi

Mater. Proc. 2023, 15(1), 80; https://doi.org/10.3390/materproc2023015080 - 04 Feb 2024

Viewed by 331

Abstract

The Foundation Industries (FIs) (chemical, cement, ceramic, glass, metal, and paper sectors) are worth GBP 52 billion to the UK economy and produce 75% of its materials and 10% of its total CO₂ emissions. The UK extractive industry annually supplies millions of [...] Read more.

The Foundation Industries (FIs) (chemical, cement, ceramic, glass, metal, and paper sectors) are worth GBP 52 billion to the UK economy and produce 75% of its materials and 10% of its total CO₂ emissions. The UK extractive industry annually supplies millions of tonnes of mineral products used in FI manufacturing processes. It is estimated that mineral extraction results in upwards of 50 million tonnes of mineral waste every year. In 2021, the British Geological Survey embarked on a series of visits to UK mineral operations to improve the understanding of mineral waste production, composition, and its potential for use. This has enabled the sharing of data and information on poorly understood stocks and flows of waste materials between different industries and led to potential new applications for use of mineral wastes in novel polymer coatings and investment casting. Full article

7 pages, 868 KiB

Open AccessProceeding Paper

Flotation of Sulphide Minerals Using Organosolv Lignin as Collector—Pilot-Scale Trials

by Panagiotis M. Angelopoulos, Georgios Anastassakis, Nikolaos Kountouris, Maria Taxiarchou, Effrosyni Koutsotheodorou, Tilemachos Pefkos, Vasileios Klepkos, Christina Samara and Giorgos Mprokos

Mater. Proc. 2023, 15(1), 81; https://doi.org/10.3390/materproc2023015081 - 06 Feb 2024

Viewed by 318

Abstract

The use of toxic chemicals as flotation reagents raises concerns about the sustainability of the process and its environmental impact. Xanthates are a family of efficient collectors that find application in the selective recovery of lead, gold and zinc ores, but they are [...] Read more.

The use of toxic chemicals as flotation reagents raises concerns about the sustainability of the process and its environmental impact. Xanthates are a family of efficient collectors that find application in the selective recovery of lead, gold and zinc ores, but they are toxic, with the majority of them being imported from eastern countries. Recently, organosolv lignin (OLN) micro- and nanoparticles have been produced and tested as collectors in the flotation of Cu minerals with positive results. The material is attractive because it is natural, biodegradable, and possesses a low carbon footprint compared to the conventional reagents. A mixed sulphide ore deposit in Halkidiki, Greece, is operated by Hellas Gold S.A., a subsidiary of Eldorado Gold. The company produces galena (PbS), sphalerite (ZnS) and Au bearing pyrite/arsenopyrite (FeS₂/FeAsS) concentrates by applying consecutive froth flotation stages. Our previous laboratory studies have shown that the partial substitution of sodium isopropyl xanthate (SIPX) with OLN is possible, without worsening the flotation performance or downgrading the concentrates’ quality. This study presents the findings of 3-stage pilot-scale flotation tests using OLN as a partial substituent of the SIPX collector on sphalerite and pyrite/arsenopyrite circuits. In the sphalerite recovery circuit, the partial replacement of SIPX with OLN (25 and 50%) resulted in an increase in Zn grade and a similar recovery compared to the standard case, while better selectivity was achieved since the Au recovery in the Zn concentrate was lower. Similarly, with the pyrite/arsenopyrite flotation circuit, the replacement of SIPX with OLN resulted in an increase in gold recovery with a parallel reduction in Pb recovery. It appears that OLN can efficiently replace part of the SIPX collector in Zn and Au flotation, producing concentrates of similar to better purity, in terms of grade and recovery of valuable metals, because of the improved selectivity of the mixed collector. The introduction of OLN in the collector mixture and the parallel reduction of SIPX drastically reduce the environmental footprint of the process. Full article

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8 pages, 2487 KiB

Open AccessProceeding Paper

Utilization of Waste Graphite for the Sustainable Production of Silicon Carbide

by Charikleia Vourgidi, Ioanna Giannopoulou, Apostolos Kourtis, Maria Magganiari and Anthimos Xenidis

Mater. Proc. 2023, 15(1), 82; https://doi.org/10.3390/materproc2023015082 - 06 Feb 2024

Viewed by 289

Abstract

Silicon carbide (SiC) is a great material for high-tech applications due to its unique mechanical, thermal and electrical properties. The Acheson method that is currently used for its production necessitates temperatures between 2000 and 2500 °C, resulting, thus, in a significant environmental footprint. [...] Read more.

Silicon carbide (SiC) is a great material for high-tech applications due to its unique mechanical, thermal and electrical properties. The Acheson method that is currently used for its production necessitates temperatures between 2000 and 2500 °C, resulting, thus, in a significant environmental footprint. In this work, an innovative approach for the production of SiC at temperatures below 1000 °C is investigated using metallic magnesium to reduce silica and utilizing waste graphite from the industrial production of graphite molds for non-ferrous metallurgy. According to the results, the molar ratios of silica to graphite and magnesium mainly affected the formation of SiC. Full article

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6 pages, 3932 KiB

Open AccessProceeding Paper

Battery Mineral Characterization—A Case Study of a Nickel Reference Material

by Lorenza Sardisco, Nikolaos Apeiranthitis, Jesal Hirani, Maximilian Franzel, Ester M. Jolis, Sari Lukkari, Radoslaw M. Michallik, Johanna Tepsell, Tim J. Pearce and Alan R. Butcher

Mater. Proc. 2023, 15(1), 83; https://doi.org/10.3390/materproc2023015083 - 18 Feb 2024

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Abstract

This study documents the geochemical and mineralogical characteristics of three nickel reference materials for the battery minerals industry: ¼ drill cores of typical nickel-rich ores, centimeter-sized chips of run-of-mine ore, and finely ground nickel concentrate, all from the same deposit. A novel aspect [...] Read more.

This study documents the geochemical and mineralogical characteristics of three nickel reference materials for the battery minerals industry: ¼ drill cores of typical nickel-rich ores, centimeter-sized chips of run-of-mine ore, and finely ground nickel concentrate, all from the same deposit. A novel aspect of this study is that we have used both traditional geoanalytical techniques for battery mineral characterization (whole-rock geochemistry, QXRD, SEM-EDS, EPMA, and automated mineralogy), as well as emerging and novel technologies (scanning micro-XRF, LIBS, FTIR, and Raman). This multidisciplinary method provides cross-verified characterization data that can be used for building mineral identification libraries and highlights the optimized combination for the analysis of these matrix types. Full article

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8 pages, 2609 KiB

Open AccessProceeding Paper

Composite Lightweight Materials with Upgraded Physicochemical Functionality and Improved Economic Feasibility

by X. Simos, M. Papageorgiou, I. Kitsou, M. E. Mamasi, T. Gikarakis, A. Ekonomakou, A. Amanatidis, G. N. Anastassakis and A. Tsetsekou

Mater. Proc. 2023, 15(1), 84; https://doi.org/10.3390/materproc2023015084 - 28 Feb 2024

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Abstract

In recent years, research has revolved around materials with superior functionality. Despite the encouraging results, their commercial use is limited due to high production costs. The major drawback of nanomaterials is their tendency to form aggregates that limit their activity. In order to [...] Read more.

In recent years, research has revolved around materials with superior functionality. Despite the encouraging results, their commercial use is limited due to high production costs. The major drawback of nanomaterials is their tendency to form aggregates that limit their activity. In order to overcome barriers, the synthesis of advanced, composite materials is proposed. These materials must exhibit high mechanical strength, adhesion between substrate and coating, and enhanced properties when compared to the substrate or the coating. In the present work, expanded perlite substrates were coated or impregnated with materials with a variety of physicochemical characteristics. The influence of the substrate’s physical properties on the performance of the produced composite materials was studied. Full article

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9 pages, 2828 KiB

Open AccessProceeding Paper

Optimization of Fe, Al, and Na Recovery from H₂-Reduced Bauxite Residue (“Red Mud”) Using Response Surface Methodology (RSM)

by Ganesh Pilla, Tobias Hertel and Yiannis Pontikes

Mater. Proc. 2023, 15(1), 85; https://doi.org/10.3390/materproc2023015085 - 22 Mar 2024

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Abstract

Bauxite residue (BR), a solid waste generated during the Bayer process for alumina production, is a polymetallic source. This study aims to investigate the recovery of Fe, Al, and Na from H₂-reduced BR pellets (under 5 vol% H₂ + 95 [...] Read more.

Bauxite residue (BR), a solid waste generated during the Bayer process for alumina production, is a polymetallic source. This study aims to investigate the recovery of Fe, Al, and Na from H₂-reduced BR pellets (under 5 vol% H₂ + 95 vol% N₂ with 45 L/h flowrate) after water leaching and magnetic separation, and to further optimize the recovery process through response surface methodology (RSM). RSM with a full factorial design was employed to evaluate the effect of process variables such as temperature (400–700 °C), time (30–120 min), and NaOH addition (10–25 wt%) for the recovery of these metals from reduced pellets. From the analysis of variance (ANOVA), the significant factors on response were identified. The Fe, Al, and Na recovery was primarily influenced by the temperature and NaOH, then the reduction time. The optimum parameters for the concurrent recovery of Fe, Al, and Na recovery were predicted to be 600 °C for 2 h with 20 wt% NaOH addition, resulting in an Fe, Al, and Na recovery of 75.8%, 84%, and 90%, respectively. The actual experimental Fe, Al, and Na recovery rates are 73.4%, 80.1%, and 87.9%, respectively. The predicted recovery rates at optimal process parameters are sufficiently accurate and within the allowable variance (<5%). Full article

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7 pages, 1689 KiB

Open AccessProceeding Paper

Mining and Mineral Exploration Projects within the Natura 2000 Area: Case Studies from Northern Finland

by Toni Eerola, Nike Luodes and Hannu Panttila

Mater. Proc. 2023, 15(1), 86; https://doi.org/10.3390/materproc2023015086 - 24 Apr 2024

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Abstract

The Rompas–Prajapat (Au-Co) and Sakatti (Ni-Cu-PGE) mineral deposits are among the only important discoveries of the last few decades in Finland. Both are partially located in Natura 2000 areas, which are among the most sensitive land use contexts in which mining and mineral [...] Read more.

The Rompas–Prajapat (Au-Co) and Sakatti (Ni-Cu-PGE) mineral deposits are among the only important discoveries of the last few decades in Finland. Both are partially located in Natura 2000 areas, which are among the most sensitive land use contexts in which mining and mineral disputes have emerged in Finland. Consequently, the project holders apply low-impact mineral exploration technologies and practice active stakeholder engagement and communication. In fact, projects seem to be mostly favored by local populations. However, because of their association with protected areas (and uranium in the case of Rompas), projects are opposed by non-governmental organizations, as well as by reindeer herders in the case of Sakatti. Project holders perform feasibility studies and environmental impact assessments. Mining licenses are applied under a new Finnish mining act and the European Union’s Raw Materials acts. Full article

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6 pages, 547 KiB

Open AccessProceeding Paper

Environmental Assessment of Replacing Fossil Fuels with Hydrogen for Motorised Equipment in the Mining Sector

by Antonis Peppas, Sotiris Kottaridis, Chrysa Politi and Paschalis Oustadakis

Mater. Proc. 2023, 15(1), 5043; https://doi.org/10.3390/materproc2023015043 - 10 Nov 2023

Viewed by 482

Abstract

To achieve the European milestone of climate neutrality by 2050, the decarbonisation of energy-intensive industries is essential. In 2022, global energy-related CO₂ emissions increased by 0.9% or 321 Mt, reaching a peak of over 36.8 Gt. A large amount of these emissions [...] Read more.

To achieve the European milestone of climate neutrality by 2050, the decarbonisation of energy-intensive industries is essential. In 2022, global energy-related CO₂ emissions increased by 0.9% or 321 Mt, reaching a peak of over 36.8 Gt. A large amount of these emissions is the result of fossil fuel usage in the motorised equipment used in mining. Heavy diesel vehicles, like excavators, wheel loaders, and dozers, are responsible for an estimated annual CO₂ emissions of 400 Mt of CO₂, accounting for approximately 1.1% of global CO₂ emissions. In addition, exhaust gases of CO₂ and NO_x endanger the personnel’s health in all mining operations, especially in underground environments. To tackle these environmental concerns and enhance environmental health, extractive industries are focusing on replacing fossil fuels with alternative fuels of low or zero CO₂ emissions. In mining, the International Council on Mining and Metals has committed to achieving net zero emissions by 2050 or earlier. Of the various alternative fuels, hydrogen (H₂) has seen a considerable rise in popularity in recent years, as H₂ combustion accounts for zero CO₂ emissions due to the lack of carbon in the burning process. When combusted with pure oxygen, it also accounts for zero NO_x formation and near-zero emissions overall. To this end, this study aims to examine the overall environmental performance of H₂-powered motorised equipment compared to conventional fossil fuel-powered equipment through Life Cycle Assessment. The assessment was conducted using the commercial software Sphera LCA for Experts, following the conventionally used framework established by ISO 14040:2006 and 14044:2006/A1:2018 and the International Life Cycle Data Handbook, consisting of (1) the goal and scope definition, (2) the Life Cycle Inventory (LCI) preparation, (3) the Life Cycle Impact Assessment (LCIA) and (4) the interpretation of the results. The results will offer an overview to support decision-makers in the sector. Full article

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