Implementation of the Circular Economy in the Raw Materials Sector

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16 pages, 2928 KiB

Open AccessArticle

Abiotic Depletion of Boron: An Update Characterization Factors for CML 2002 and ReCiPe

by Ayşenur Çolak, Bertrand Laratte, Birol Elevli and Semra Çoruh

Minerals 2022, 12(4), 435; https://doi.org/10.3390/min12040435 - 31 Mar 2022

Cited by 2 | Viewed by 1798

Abstract

The risk of resource depletion for future generations of humanity is often cited as an important issue. The choice of impact categories and characterization models for resource extraction in LCA is no more precise than other impact categories and models. This means that more discussion is needed on the use of resources. In this article, the potential depletion of Boron and Boron minerals (Colemanite, Ulexite, Tincal) are studied. These minerals have a big role for the world and for Turkey; however, this resource is limited. Using the life cycle assessment methodology, one can estimate the resource depletion through the indicator “abiotic resource depletion”. Several models can evaluate this indicator, but the most used models are ReCiPe and CML (that is the previous attempt of ReCiPe) methods. Here, we estimated the damage that is done to natural resource scarcity. The values that are calculated by these two methods were compared to identify the potential evolution of the model and to observe the gap between these two models. The ReCiPe method refers to the average amount of extra ore that is produced in the future to extract 1 kg of boron ore or boron minerals resource. On the other hand, The CML method depends on the final reserve amount in terms of depletion. The results show no depletion shortly for boron ore and boron minerals. Correlation coefficients were calculated in the ReCiPe method, and ‘high uncertainty’ was estimated since R² < 0.8. This research highlights the fact that there is the necessity to propose different impact factors for the various minerals and not only for boron (that is done today). Full article

(This article belongs to the Topic Implementation of the Circular Economy in the Raw Materials Sector)

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18 pages, 10422 KiB

Open AccessArticle

Metallic Copper (Cu[0]) Obtained from Cu²⁺-Rich Acidic Mine Waters by Two Different Reduction Methods: Crystallographic and Geochemical Aspects

by Javier Sánchez-España, Andrey Ilin and Iñaki Yusta

Minerals 2022, 12(3), 322; https://doi.org/10.3390/min12030322 - 04 Mar 2022

Cited by 2 | Viewed by 3126

Abstract

The recovery of valuable metals from different types of wastes has become of prime strategic interest given the scarcity of primary critical raw materials at international scale. Implementation of new methods or refinement of classical techniques with modern technological advances is, therefore, an active research field. Mine wastes are of special interest because their high metal concentrations make them environmentally harmful and economically profitable at the same time. In this study, we evaluated two different methods of Cu recovery from extremely acidic mine waters seeping from wastes and abandoned mines in SW Spain. Through a series of different batch experiments, we compared the method efficiency and crystallographic properties of elemental copper (Cu[0]) obtained by reduction of Cu²⁺ ions by (1) chemical reduction using ascorbic acid at different environmental conditions of pH (1.50–3.95), temperature (25–80 °C) and ascorbic acid concentration (10 mM to 0.1 M), and (2) classical cementation method with scrap iron at pH 1.50 and 25 °C. Our study demonstrates that the precipitation of Cu[0] can take place at pH 3.95 and low AA concentrations (0.1 M), resulting in large (µm-scale), perfectly developed crystals of copper with pseudoprismatic to acicular habit after 24 h of aging, likely through formation of a transient compound consisting in Cu²⁺-ascorbate and/or cuprite (Cu₂O) nanocolloids. Reduction experiments at higher AA concentrations (0.1 M) showed faster precipitation kinetics and resulted in high-purity (>98%) copper suspensions formed by subrounded nanoparticles. The AA method, however, yielded very low recovery rates (15–25%) because of the low pH values considered. The cementation method, which produced tree-like aggregates formed by sub-micron crystals arranged in different directions, proved to be much more efficient (>98% recovery) and cost-effective. Full article

(This article belongs to the Topic Implementation of the Circular Economy in the Raw Materials Sector)

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19 pages, 4775 KiB

Open AccessArticle

Preliminary Risk Assessment of Dam Failure at the Location of the Cukaru Peki Deposit, Bor (Serbia)

by Dragana Nišić

Minerals 2021, 11(10), 1126; https://doi.org/10.3390/min11101126 - 14 Oct 2021

Cited by 3 | Viewed by 1962

Abstract

Industrial waste landfills, as evidenced by frequent accidents occurring in recent years, are regarded as one of the most hazardous facilities in the world. For the adequate management of a landfill, risk assessments of dam failures should be performed before operations begin. This paper deals with the preliminary risk assessment used for the tailings and pyrite concentrate storage facilities, as well as the drainage waters reservoir, which are currently at the development and construction stage in the Cukaru Peki deposit located in eastern Serbia. The research was conducted to establish the facts and level of risk at an early stage to allow for timely prevention of potential accidents and bring operational practice in line with design requirements. The annual failure probability was estimated using a semi-empirical method, based on the dam stability factor. While, the framework proposed by the New Zealand Society on Large Dams was applied to assess the consequences of potential failures. The risk was assessed as a function of accident probability and the severity of possible consequences, and a 7 × 7 risk matrix was applied for analysis and evaluation. The level of dam failure risk at the location of the Cukaru Peki deposit was preliminarily assessed as moderate and conditionally tolerable, based on a low estimated probability of accident and a significant severity of consequences. Once the operation of these facilities starts risk assessments should be regularly updated, in order to maintain this level, and in accordance with the current situation, the modelling of specific accident scenarios should be included. Full article

(This article belongs to the Topic Implementation of the Circular Economy in the Raw Materials Sector)

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