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Advances in Processing and Characterization of Mineral Materials
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Advances in Processing and Characterization of Mineral Materials

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Advanced Materials Characterization".

Deadline for manuscript submissions: closed (20 April 2023) | Viewed by 30315

Special Issue Editors

Prof. Dr. Yuanbo Zhang

E-Mail Website
Guest Editor
School of Minerals Processing & Bioengineering, Central South University, Changsha 410083, China
Interests: mineral functional materials; mineral-metallurgy-materials integration; mineral processing and metallurgical engineering
Dr. Bingbing Liu

E-Mail Website
Guest Editor
School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
Interests: mineral-metallurgy-materials integration; metallurgical engineering; separation; mineral functional materials; minerals processing; recycling of industrial solid wastes; industrial water treatment
Special Issues, Collections and Topics in MDPI journals
Dr. Zijian Su

E-Mail Website
Guest Editor
School of Minerals Processing & Bioengineering, Central South University, Changsha 410083, China
Interests: mineral processing and metallurgical engineering; mineral functional materials; recycling of industrial solid wastes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Functional minerals are the materials inspired by geological systems originating from the billion-years-long
history of the Earth. Each of them has a unique chemical composition and a structure that determines its interesting properties and possible functions. The functions of mineral materials include adsorption, ions-exchange, catalysts, magnetism, immobilization, ceramics and micronutrient bearing mineral fertilizer. Layered clay minerals, and zeolite-like structures and layered double hydroxides (LDHs) are also particularly suited to such a defined functionalization. The modification and design principles on the thermodynamics and kinetics aspects and characterization techniques of functional mineral materials are also welcome. This Special Issue, collecting interdisciplinary studies, will provide the current top trends in the innovative functionalization techniques for mineral materials. Reports, investigations, articles, reviews and short communications on the unique properties of functionalized materials and their expected applications are also welcome.

Thank you for your support!

Prof. Dr. Yuanbo Zhang
Dr. Bingbing Liu
Dr. Zijian Su
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • mineral materials design, modification and preparaion
  • thermodynamics and kinetics
  • phase trasformation and reconstruction
  • functionalized minerals
  • indusrial solid wastes derived materials
  • mineral-based building materials
  • mineral-based functional ceramics
  • mineral fertilizers for crops
  • minerals-metallurgy-materials integration

Published Papers (15 papers)

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Research

15 pages, 11165 KiB  
Article
Mn-Doped Spinel for Removing Cr(VI) from Aqueous Solutions: Adsorption Characteristics and Mechanisms
by Manman Lu, Zijian Su, Yuanbo Zhang, Hanquan Zhang, Jia Wang, Qian Li and Tao Jiang
Materials 2023, 16(4), 1553; https://doi.org/10.3390/ma16041553 - 13 Feb 2023
Viewed by 1205
Abstract
In this study, the manganese (Mn) was doped in the MnFe2O4 crystal by the solid-phase synthesis method. Under the optimum conditions (pH = 3), the max removal rate and adsorption quantity of Cr(VI) on MnFe2O4 adsorbent obtain [...] Read more.
In this study, the manganese (Mn) was doped in the MnFe2O4 crystal by the solid-phase synthesis method. Under the optimum conditions (pH = 3), the max removal rate and adsorption quantity of Cr(VI) on MnFe2O4 adsorbent obtain under pH = 3 were 92.54% and 5.813 mg/g, respectively. The DFT calculation results indicated that the adsorption energy (Eads) between HCrO4− and MnFe2O4 is −215.2 KJ/mol. The Cr(VI) is mainly adsorbed on the Mn atoms via chemical bonds in the form of HCrO4−. The adsorption of Mn on the MnFe2O4 surface belonged to chemisorption and conformed to the Pseudo-second-order equation. The mechanism investigation indicated that the Mn in MnFe2O4 has an excellent enhancement effect on the Cr(VI) removal process. The roles of Mn in the Cr(VI) removal process included two parts, providing adsorbing sites and being reductant. Firstly, the Cr(VI) is adsorbed onto the MnFe2O4 via chemisorption. The Mn in MnFe2O4 can form ionic bonds with the O atoms of HCrO4−/CrO42−, thus providing the firm adsorbing sites for the Cr(VI). Subsequently, the dissolved Mn(II) can reduce Cr(VI) to Cr(III). The disproportionation of oxidized Mn(III) produced Mn(II), causing Mn(II) to continue to participate in the Cr(VI) reduction. Finally, the reduced Cr(III) is deposited on the MnFe2O4 surface in the form of Cr(OH)3 colloids, which can be separated by magnetic separation. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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12 pages, 4517 KiB  
Article
Formation and Inhibition Mechanism of Na8SnSi6O18 during the Soda Roasting Process for Preparing Na2SnO3
by Zijian Su, Shuo Liu, Benlai Han, Yuanbo Zhang and Tao Jiang
Materials 2022, 15(24), 8718; https://doi.org/10.3390/ma15248718 - 07 Dec 2022
Viewed by 950
Abstract
To produce Na2SnO3, which is widely used in the ceramics and electroplating industries, a novel process for the preparation of sodium stannate from cassiterite concentrates was developed successfully by the authors’ group. It was found that sodium stannosilicate (Na8 [...] Read more.
To produce Na2SnO3, which is widely used in the ceramics and electroplating industries, a novel process for the preparation of sodium stannate from cassiterite concentrates was developed successfully by the authors’ group. It was found that sodium stannosilicate (Na8SnSi6O18) was easily formed due to the main gangue of quartz in cassiterite concentrates, which was almost insoluble and decreased the quality of Na2SnO3. The formation and transitions of Na8SnSi6O18 in the SnO2–SiO2–Na2CO3 system roasted under a CO–CO2 atmosphere were determined. The results indicated that the formation of Na8SnSi6O18 could be divided into two steps: SnO2 reacted with Na2CO3 to form Na2SnO3, and then Na2SnO3 was rapidly combined with SiO2 and Na2CO3 to form low melting point Na8SnSi6O18. In addition, Na8SnSi6O18 can be decomposed into Na2SiO3 and Na2SnO3 by using excess Na2CO3. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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23 pages, 7304 KiB  
Article
High-Iron Bauxite Residue (Red Mud) Valorization Using Hydrochemical Conversion of Goethite to Magnetite
by Andrei Shoppert, Dmitry Valeev, Mamodou Malal Diallo, Irina Loginova, Marie Constance Beavogui, Abdukhakim Rakhmonov, Yevgeniy Ovchenkov and Denis Pankratov
Materials 2022, 15(23), 8423; https://doi.org/10.3390/ma15238423 - 26 Nov 2022
Cited by 15 | Viewed by 1756
Abstract
Bauxite residue (BR), also known as red mud, is a byproduct of the alumina production using the Bayer process. This material is not used to make iron or other iron-containing products worldwide, owing to its high content of sodium oxide and other impurities. [...] Read more.
Bauxite residue (BR), also known as red mud, is a byproduct of the alumina production using the Bayer process. This material is not used to make iron or other iron-containing products worldwide, owing to its high content of sodium oxide and other impurities. In this study, we investigated the hydrochemical conversion of goethite (FeOOH) to magnetite (Fe3O4) in high-iron BR from the Friguia alumina refinery (Guinea) by Fe2+ ions in highly concentrated alkaline media. The simultaneous extraction of Al and Na made it possible to obtain a product containing more than 96% Fe3O4. The results show that the magnetization of Al-goethite and Al-hematite accelerates the dissolution of the Al from the iron mineral solid matrix and from the desilication product (DSP). After ferrous sulfate (FeSO4·7H2O) was added directly at an FeO:Fe2O3 molar ratio of 1:1 at 120 °C for 150 min in solution with the 360 g L−1 Na2O concentration, the alumina extraction ratio reached 96.27% for the coarse bauxite residue size fraction (Sands) and 87.06% for fine BR obtained from red mud. The grade of iron (total iron in the form of iron elements) in the residue can be increased to 69.55% for sands and 58.31% for BR. The solid residues obtained after leaching were studied by XRD, XRF, TG-DTA, VSM, Mössbauer spectroscopy, and SEM to evaluate the conversion and leaching mechanisms, as well as the recovery ratio of Al from various minerals. The iron-rich residues can be used in the steel industry or as a pigment. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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13 pages, 4027 KiB  
Article
Research on Three-Dimensional Porous Composite Nano-Assembled α-MnO2/Reduced Graphene Oxides and Their Super-Capacitive Performance
by Liming Luo, Huiyun Peng, Hongjuan Sun, Tongjiang Peng and Mingliang Yuan
Materials 2022, 15(23), 8406; https://doi.org/10.3390/ma15238406 - 25 Nov 2022
Viewed by 970
Abstract
A series of three-dimensional porous composite α-MnO2/reduced graphene oxides (α-MnO2/RGO) were prepared by nano-assembly in a hydrothermal environment at pH 9.0–13.0 using graphene oxide as the precursor, KMnO4 and MnCl2 as the manganese sources and F− [...] Read more.
A series of three-dimensional porous composite α-MnO2/reduced graphene oxides (α-MnO2/RGO) were prepared by nano-assembly in a hydrothermal environment at pH 9.0–13.0 using graphene oxide as the precursor, KMnO4 and MnCl2 as the manganese sources and F− as the control agent of the α-MnO2 crystal form. The α-MnO2/RGO composites prepared at different hydrothermal pH levels presented porous network structures but there were significant differences in these structures. The special pore structure promoted the migration of ions in the electrolyte in the electrode material, and the larger specific surface area promoted the contact between the electrode material and the electrolyte ions. The introduction of graphene solved the problem of poor conductivity of MnO2, facilitated the rapid transfer of electrons, and significantly improved the electrochemical performance of materials. When the pH was 12.0, the specific surface area of the 3D porous composite material αMGs-12.0 was 264 m2·g−1, and it displayed the best super-capacitive performance; in Na2SO4 solution with 1.0 mol·L−1 electrolyte, the specific capacitance was 504 F·g−1 when the current density was 0.5 A·g−1 and the specific capacitance retention rate after 5000 cycles was 88.27%, showing that the composite had excellent electrochemical performance. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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12 pages, 2379 KiB  
Article
Improving the Properties of Magnetite Green Pellets with a Novel Organic Composite Binder
by Shuo Liu, Yuanbo Zhang, Zijian Su and Tao Jiang
Materials 2022, 15(19), 6999; https://doi.org/10.3390/ma15196999 - 09 Oct 2022
Cited by 5 | Viewed by 1441
Abstract
A novel composite binder (humic acid modified bentonite, HAMB) and two other binders (bentonite and Modified humic acid, MHA) were used to explore the effects of binders on the properties of magnetite green pellets in this study. The results of green pellet properties [...] Read more.
A novel composite binder (humic acid modified bentonite, HAMB) and two other binders (bentonite and Modified humic acid, MHA) were used to explore the effects of binders on the properties of magnetite green pellets in this study. The results of green pellet properties and drying tests show that the low doses of a humic substance-based binder can achieve the same effect as high doses of bentonite binder. A humic substance-based binder could be a promising organic binder to replace bentonite. Meanwhile, the influence mechanism of adding different binders on the strength of green pellet was discussed, and the relationship between moisture content in the pellet and the compression strength of three binders was determined. A TG-DSC analysis found that the novel composite binder (HAMB) was not a simple mix of humic acid and bentonite, in which a humic substance could change the structure of bentonite and reduce the thermal stability of bentonite, causing the HAMB composite binder to have a high decomposition temperature. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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16 pages, 7337 KiB  
Article
The Transition of Mg-Containing Phases and Recovery of NaCl in Molten Salt Chloride Slags at High Temperature
by Feng Chen, Yuekai Wen, Yufeng Guo, Shuai Wang, Lingzhi Yang, Yu Zheng, Dongyue Li and Yuqiao Ren
Materials 2022, 15(17), 5983; https://doi.org/10.3390/ma15175983 - 30 Aug 2022
Viewed by 1332
Abstract
The molten salt chlorination method is more suitable to produce TiCl4 using titanium-containing materials with high contents of CaO and MgO in China. However, there is a large amount of molten salt chloride slags generated from the molten salt chlorination process, which [...] Read more.
The molten salt chlorination method is more suitable to produce TiCl4 using titanium-containing materials with high contents of CaO and MgO in China. However, there is a large amount of molten salt chloride slags generated from the molten salt chlorination process, which contains a variety of chlorides and is difficult to treat, often causing serious environmental problems such as direct piling or landfilling. A novel process was proposed to deal with molten salt chloride slags, and calcium chloride could be effectively removed by this process (as in our previous study). However, magnesium chloride is another impurity which can deteriorate the density and viscosity of the molten salt; it is often found in higher contents, and should be also removed from molten salt chloride slags to efficiently recycle NaCl in novel processes. Na2SiO3 is added to the molten salt chloride slags in the molten state to produce the Mg-containing solid phase, which could be separated with the molten NaCl in novel processes. Thus, the transition of Mg-containing phases and the recovery of NaCl in molten salt chloride slags at high temperature in a novel process were systematically investigated in this work, including thermodynamic analysis, the phase transition behavior of Mg-containing phases, NaCl recovery, etc. The removal rate of Mg was 99.56% when the molar ratio of MgCl2:Na2SiO3 was 1:1.5 at 1273 K and in a N2 atmosphere. The recovery rate of NaCl from the molten salt chlorination slag was 97.62% and the purity of NaCl obtained was 99.35 wt%, which could be used in the molten salt chlorination process. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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17 pages, 6215 KiB  
Article
Synthesis of Ni/Y2O3 Nanocomposite through USP and Lyophilisation for Possible Use as Coating
by Tilen Švarc, Srećko Stopić, Žiga Jelen, Matej Zadravec, Bernd Friedrich and Rebeka Rudolf
Materials 2022, 15(8), 2856; https://doi.org/10.3390/ma15082856 - 13 Apr 2022
Cited by 3 | Viewed by 1822
Abstract
The Ni/Y2O3 catalyst showed high catalytic activity. Based on this, the aim of this study was to create Ni/Y2O3 nanocomposites powder with two innovative technologies, Ultrasonic Spray Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition [...] Read more.
The Ni/Y2O3 catalyst showed high catalytic activity. Based on this, the aim of this study was to create Ni/Y2O3 nanocomposites powder with two innovative technologies, Ultrasonic Spray Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition of the generated aerosols in an N2/H2 reduction atmosphere caused a complete decomposition of the nickel (II) nitrate to elemental Ni, which became trapped on the formed Y2O3 nanoparticles. The Ni/Y2O3 nanocomposite particles were captured via gas washing in an aqueous solution of polyvinylpyrrolidone (PVP) in collection bottles. PVP was chosen for its ability to stabilise nano-suspensions and as an effective cryoprotectant. Consequently, there was no loss or agglomeration of Ni/Y2O3 nanocomposite material during the lyophilisation process. The Ni/Y2O3 nanocomposite powder was analysed using ICP-MS, SEM-EDX, and XPS, which showed the impact of different precursor concentrations on the final Ni/Y2O3 nanocomposite particle composition. In a final step, highly concentrated Ni/Y2O3 nanocomposite ink (Ni/Y2O3 > 0.140 g/mL) and test coatings from this ink were prepared by applying them on a white matte photo paper sheet. The reflection curve of the prepared Ni/Y2O3 nanocomposite coating showed a local maximum at 440 nm with a value of 39% reflection. Given that Ni is located on the surface of the Ni/Y2O3 nanocomposite in the elemental state and according to the identified properties, tests of the catalytic properties of this coating will be performed in the future. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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17 pages, 17363 KiB  
Article
An Experimental Study on Enhancing Microbial Desulfurization of Sulfide Ores Using Ultrasonic Treatment
by Wei Pan, Ruge Yi, Zhigang Liao and Lingrong Yang
Materials 2022, 15(7), 2620; https://doi.org/10.3390/ma15072620 - 02 Apr 2022
Cited by 2 | Viewed by 1546
Abstract
Ultrasonic technology is being increasingly explored in minerals processing. In this paper, ultrasonic treatment was introduced as a novel method for microbial desulfurization of sulfide ores. A Box–Behnken experiment was performed to find the best combination of factor levels for the following experiments; [...] Read more.
Ultrasonic technology is being increasingly explored in minerals processing. In this paper, ultrasonic treatment was introduced as a novel method for microbial desulfurization of sulfide ores. A Box–Behnken experiment was performed to find the best combination of factor levels for the following experiments; consequently, the combination of factor levels at the maximum 5-day average desulfurization rate at 20 g of ore was a particle size of 120–140 mesh, a shaker speed of 175 rpm, and a dosage of 111 mL of bacterial solution. Under these conditions, a microbial desulfurization experiment of sulfide ores by ultrasonic treatment was carried out, and the effect of the particle size, the ultrasonic action time, and the ultrasonic power were investigated. Results indicated that the ultrasonic effect was not significant for ore samples with larger particle sizes, and the appropriate increase in ultrasonic action time was beneficial to the improvement of desulfurization rate, but the effect showed a decreasing trend when it exceeded 50 min, and the best desulfurization effect was achieved when the power was 300 W. This study demonstrated that the effect of microbial desulfurization can be greatly enhanced by ultrasonic treatment. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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13 pages, 3782 KiB  
Article
Physicochemical Aspects of Oxidative Consolidation Behavior of Manganese Ore Powders with Various Mn/Fe Mass Ratios for Pellet Preparation
by Yuanbo Zhang, Bei Zhang, Bingbing Liu, Junjie Huang, Jing Ye and Yuelong Li
Materials 2022, 15(5), 1722; https://doi.org/10.3390/ma15051722 - 25 Feb 2022
Cited by 1 | Viewed by 1300
Abstract
With the depletion of rich manganese ore resources, plentiful manganese ore powders with various Mn/Fe mass ratios are produced. The physicochemical aspects of oxidative consolidation behavior of manganese ores with various Mn/Fe mass ratios were investigated in this work to determine whether manganese [...] Read more.
With the depletion of rich manganese ore resources, plentiful manganese ore powders with various Mn/Fe mass ratios are produced. The physicochemical aspects of oxidative consolidation behavior of manganese ores with various Mn/Fe mass ratios were investigated in this work to determine whether manganese ore powders with high iron content (Fe-Mn ore) can be prepared as high-quality pellets. Physicochemical properties of the pellets were investigated, including cold compression strength (CCS), phase transformation, microstructural evolution, Vickers hardness (HV), porosity, and lattice parameter. CCS testing indicated that the strength of roasted Fe-Mn ore pellets was observably lower than that of pure hematite or manganese ore pellets. Phase and morphology results showed that in Fe-Mn ore pellets, an Mn ferrite phase was generated between hematite and pyrolusite particles. However, newborn Mn ferrites and hematite had an obvious crystal boundary in the crystallographic particles. Moreover, poorly crystallized Mn ferrite particles were evident, along with Mn and Fe element concentration gradients, due to the inadequate diffusion of metal ions. This resulted in poor mechanical properties of the Fe-Mn ore pellets. A temperature over 1275 ∘C and a roasting time of 15 min is required for the oxidative consolidation of Fe-Mn ores. In such optimized cases, Mn, Fe, O, and Al elements were uniformly distributed in the well-crystallized Mn ferrite grains, which provided favorable mineralogy for the consolidation of Fe-Mn ore powders. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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12 pages, 2552 KiB  
Article
Biochemical Fulvic Acid Modification for Phosphate Crystal Inhibition in Water and Fertilizer Integration
by Jianyun Li, Zihan Nie, Zhao Fan, Chunguang Li, Bingbing Liu, Quanxian Hua and Cuihong Hou
Materials 2022, 15(3), 1174; https://doi.org/10.3390/ma15031174 - 03 Feb 2022
Cited by 2 | Viewed by 1615
Abstract
Biochemical fulvic acid (BFA), produced by organic wastes composting, is the complex organic matter with various functional groups. A novel modified biochemical fulvic acid (MBFA) which possessed stronger chelating ability had been synthesized by the grafting copolymerization of BFA and acrylic acid (AA). [...] Read more.
Biochemical fulvic acid (BFA), produced by organic wastes composting, is the complex organic matter with various functional groups. A novel modified biochemical fulvic acid (MBFA) which possessed stronger chelating ability had been synthesized by the grafting copolymerization of BFA and acrylic acid (AA). Results showed that MBFA effectively inhibited the crystallization of calcium phosphate and increased the concentration of phosphate in water solution. The optimum reaction conditions optimized by Box–Behnken design and response surface methodology were reaction temperature 69.24 °C, the mass of monomer to fulvic acid ratio 0.713, the initiator dosage 19.78%, and phosphate crystal-inhibition extent was 96.89%. IR spectra demonstrated AA was grafted onto BFA. XRD data and SEM images appeared the formation and growth of calcium phosphate crystals was effectively inhibited by MBFA. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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14 pages, 10261 KiB  
Article
Selective Scandium (Sc) Extraction from Bauxite Residue (Red Mud) Obtained by Alkali Fusion-Leaching Method
by Andrei Shoppert, Irina Loginova, Julia Napol’skikh, Aleksey Kyrchikov, Leonid Chaikin, Denis Rogozhnikov and Dmitry Valeev
Materials 2022, 15(2), 433; https://doi.org/10.3390/ma15020433 - 07 Jan 2022
Cited by 17 | Viewed by 2577
Abstract
Bauxite residue, known as “red mud,” is a potential raw material for extracting rare-earth elements (REEs). The main REEs (Sc, Y, La, Ce, Nd, Nb, and Sm) from the raw bauxite are concentrated in RM after the Bayer leaching process. The earlier worldwide [...] Read more.
Bauxite residue, known as “red mud,” is a potential raw material for extracting rare-earth elements (REEs). The main REEs (Sc, Y, La, Ce, Nd, Nb, and Sm) from the raw bauxite are concentrated in RM after the Bayer leaching process. The earlier worldwide studies were focused on the scandium (Sc) extraction from RM by concentrated acids to enhance the extraction degree. This leads to the dissolution of major oxides (Fe2O3 and Al2O3) from RM. This article studies the possibility of selective Sc extraction from alkali fusion red mud (RMF) by diluted nitric acid (HNO3) leaching at pH ≥ 2 to prevent co-dissolution of Fe2O3. RMF samples were analyzed by X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and inductively coupled plasma mass spectrometry (ICP-MS). It was revealed that Sc concentration in RMF can reach up to 140–150 mg kg−1. Sc extraction was 71.2% at RMF leaching by HNO3 at pH 2 and 80 °C during 90 min. The leaching solution contained 8 mg L−1 Sc and a high amount of other REEs in the presence of relatively low concentrations of impurity elements such as Fe, Al, Ti, Ca, etc. The kinetic analysis of experimental data by the shrinking core model showed that Sc leaching process is limited by the interfacial diffusion and the diffusion through the product layer. The apparent activation energy (Ea) was 19.5 kJ/mol. The linear dependence of Sc extraction on magnesium (Mg) extraction was revealed. According to EPMA of RMF, Sc is associated with iron minerals rather than Mg. This allows us to conclude that Mg acts as a leaching agent for the extraction of Sc presented in the RMF in an ion-exchangeable phase. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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15 pages, 2682 KiB  
Article
Detection and Quantification of Precious Elements in Astrophyllite Mineral by Optical Spectroscopy
by Altaf Ahmad, Shahab Ahmed Abbasi, Muhammad Hafeez, Taj Muhammad Khan, Muhammad Rafique, Nasar Ahmed, Pervaiz Ahmad, Mohammad Rashed Iqbal Faruque, Mayeen Uddin Khandaker and Muhammad Javed
Materials 2021, 14(21), 6277; https://doi.org/10.3390/ma14216277 - 21 Oct 2021
Cited by 4 | Viewed by 1517
Abstract
With many advantages over well-established methods, laser induced breakdown spectroscopy (LIBS) has emerged as a useful analytical technique for the compositional analysis of multi-elemental geological materials. In this study, LIBS was employed for qualitative and quantitative analysis of a rare mineral, astrophyllite, bearing [...] Read more.
With many advantages over well-established methods, laser induced breakdown spectroscopy (LIBS) has emerged as a useful analytical technique for the compositional analysis of multi-elemental geological materials. In this study, LIBS was employed for qualitative and quantitative analysis of a rare mineral, astrophyllite, bearing precious elements of industrial and technological interest. The experiment was carried out using second harmonic generation of Nd:YAG laser of pulse width 5 ns and repetition rate of 10 Hz. Microplasma was produced by focusing laser beam on an astrophyllite target, and optical emissions from the generated plasma were recorded in the spectral range of 200–720 nm with the help of a LIBS2000+ detection system. On analyzing the optical spectra, existence of 15 elements in astrophyllite target were revealed. These elements include: Ti, W, Ag, Al, Ba, Ca, Cr, Cu, Fe, Li, Mg, Na, Ni, Si and H. For quantification, calibration-free method was used. Only ten elements, namely Ti, W, Fe, Cr, Cu, Ca, Mg, Ni, Si and Al, were quantified with relative weight concentrations of 55.39%, 18.79%, 18.30%, 4.05%, 2.66, 0.43%, 0.18%, 0.12%, 0.06% and 0.02%, respectively. To benchmark these results, XRF analysis was performed, which confirmed the presence of all the elements detected in the optical spectrum of the sample, except for Na, Li, and H. The concentrations of these ten elements as measured by XRF were in reasonable agreement, especially for the major elements. The presence of a significant amount of Ti and W in an astrophyllite sample, found in Pakistan, highlights the economic value of this mineral. This study may be of further interest in commissioning LIBS technology for exploration of minerals in the region. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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13 pages, 4190 KiB  
Article
Effect of Finely Ground Limestone and Dolomite on Compression Strength and Reduction Swelling of Vanadium-Titanium Pellets
by Hao Liu, Shihong Peng, Ke Zhang, Yuelin Qin, Fei Meng, Wenchao He, Weiqiang Liu, Min Chen and Lixiang Yan
Materials 2021, 14(16), 4433; https://doi.org/10.3390/ma14164433 - 07 Aug 2021
Cited by 3 | Viewed by 2099
Abstract
Vanadium−titanium magnetite (VTM) is an important raw material for ironmaking under the situation of increasingly demanding scarce resources. To further improve the metallurgical properties of pellets, and to satisfy the requirements of blast furnace slag basicity, finely ground dolomite and limestone have been [...] Read more.
Vanadium−titanium magnetite (VTM) is an important raw material for ironmaking under the situation of increasingly demanding scarce resources. To further improve the metallurgical properties of pellets, and to satisfy the requirements of blast furnace slag basicity, finely ground dolomite and limestone have been added to the pellet. In this study, the effect of finely ground dolomite and limestone on the metallurgical properties (green pellet drop strength, cold compression strength, reduction swelling index, and microscopic mineral structure) of VTM pellets were investigated. With the addition of finely ground dolomite and limestone, the drop strength of the green pellet was improved. The effect of adding finely ground limestone was greater than adding finely ground dolomite. Adding more finely ground dolomite and limestone compared to pellets without limestone and dolomite, the cold compression strength was decreased, which was attributed to the decomposition of limestone and dolomite during the induration of pellets. With the addition of dolomite, the reduction swelling index (RSI) increased firstly and then decreased. When the basicity of the pellet was 0.54 to 0.94, the slag phase with the lowest melting point was formed, corresponding to the maximum of the reduction swelling index. For the pellets with added limestone, the reduction swelling of the pellets deteriorated. The reduction index of the pellets increased and reached the maximum (26.6%) at a basicity of 1.54, which belongs to abnormal swelling. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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18 pages, 4221 KiB  
Article
Phase Composition of Silica Fume—Portland Cement Systems Formed under Hydrothermal Curing Evaluated by FTIR, XRD, and TGA
by Eva Kuzielová, Michal Slaný, Matúš Žemlička, Jiří Másilko and Martin Tchingnabé Palou
Materials 2021, 14(11), 2786; https://doi.org/10.3390/ma14112786 - 24 May 2021
Cited by 20 | Viewed by 2845
Abstract
Two substitution levels of Portland cement by silica fume (SF; 30 and 50 mass%) and three hydrothermal treatment regimes (0.5, 1.2, and 2 MPa and 165, 195, and 220 °C for 7 days, respectively) were selected for the investigation of high-temperature phase formation. [...] Read more.
Two substitution levels of Portland cement by silica fume (SF; 30 and 50 mass%) and three hydrothermal treatment regimes (0.5, 1.2, and 2 MPa and 165, 195, and 220 °C for 7 days, respectively) were selected for the investigation of high-temperature phase formation. A combination of thermogravimetric, X-ray diffraction, and Fourier transform infrared analyses in the mid-IR region was used to overcome the shortcomings of individual techniques for the identification of these complex systems. Changes in molecular water amounts, the polymerization degree of silicate chains, or their decomposition due to transformations and crystallization of phases at hydrothermal conditions were observed and discussed concerning composition. Contrary to the calciochondrite, hydrogrossular phases, α-C2SH, and jaffeite detected in the systems without SF, a decrease in CaO/SiO2 ratio resulted in the formation of stable tobermorite in the case of 30 mass% SF, whilst calcium hydrogen silicate, gyrolite, and cowlesite were identified as more thermally stable phases in the samples with 50 mass% SF. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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18 pages, 10101 KiB  
Article
Sustainable and Clean Utilization of Yellow Phosphorus Slag (YPS): Activation and Preparation of Granular Rice Fertilizer
by Cuihong Hou, Luyi Li, Lishuang Hou, Bingbing Liu, Shouyu Gu, Yuan Yao and Haobin Wang
Materials 2021, 14(8), 2080; https://doi.org/10.3390/ma14082080 - 20 Apr 2021
Cited by 5 | Viewed by 2696
Abstract
Yellow phosphorus slag (YPS) is a typical industrial solid waste, while it contains abundant silicon micronutrient required for the growth of rice. The key scientific problem to use the YPS as rice fertilizer is how to activate the slag efficiently during the phosphorite [...] Read more.
Yellow phosphorus slag (YPS) is a typical industrial solid waste, while it contains abundant silicon micronutrient required for the growth of rice. The key scientific problem to use the YPS as rice fertilizer is how to activate the slag efficiently during the phosphorite reduction smelting process. In this work, an alkaline rice fertilizer from the activated YPS was successfully prepared to use the micronutrients. Thermodynamic analyses of SiO2-CaO, SiO2-CaO-Al2O3, and SiO2-CaO-Al2O3-MgO systems were discussed to optimize the acidity for reduction smelting. Results showed that the reduction smelting followed by the water quenching process can realize the reduction of phosphorite and activation of YPS synchronously. Ternary acidity m(SiO2)/(m(CaO) + m(MgO)) of 0.92 is suitable for the reduction smelting and activation of the slag. After smelting, the molten YPS can be effectively activated by water quenching, and 78.28% P, 90.03% Ca, and 77.12% Si in the YPS are activated, which can be readily absorbed by the rice roots. Finally, high-strength granular rice fertilizers with a particle size of Φ2–4 mm were successfully prepared from the powdery nitrogen-phosphorus-potassium (NPK) and activated YPS mixture. Full article
(This article belongs to the Special Issue Advances in Processing and Characterization of Mineral Materials)
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