Special Issue "Cleaner Production in Mineral Processing"

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Processing and Metallurgy".

Deadline for manuscript submissions: closed (15 June 2020).

Special Issue Editor

Prof. Dr. Luis A. Cisternas
Website1 Website2
Guest Editor
Department of Chemical Engineering and Mineral Process, Universidad of Antofagasta, 1240000 Antofagasta, Chile
Interests: modeling; design; optimization; uncertainty; flotation; heap leaching; tailing; seawater
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Special Issue Information

Dear Colleagues,

The most pressing environmental problems of base metals production are solid waste production, gaseous emissions, and high energy use. Most of the present solutions to clean up post-mining base metals production can be characterized as incremental, end-of-pipe technologies. More sophisticated, radical solutions are scarcely implemented. This Special Issue on Cleaner Production in Mineral Processing focuses on strategies and technologies to identify options to minimize waste and emissions out of the mineral processes through source reduction. Examples are technologies to reduce the effect of tailing by modification of the process to avoid fine particles and acid mine drainage agents in the tailing. Other examples are the reuse of waste, new process and technologies with low waste, and substitution of raw material and energy by renewable material and energy. The development of cleaner production is essential for the adoption of a circular economy.

Prof. Dr. Luis A. Cisternas
Guest Editor

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 papers will be 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. Minerals is an international peer-reviewed open access monthly 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 1600 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

  • Waste reduction
  • Tailing
  • Circular economy
  • Substitution of raw material by renewable material
  • Substitution of energy by renewable energy

Published Papers (9 papers)

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Research

Open AccessArticle
Improving the Flocculation Performance of Clay-Based Tailings in Seawater: A Population Balance Modelling Approach
Minerals 2020, 10(9), 782; https://doi.org/10.3390/min10090782 - 04 Sep 2020
Abstract
A population balance model described the flocculation of clay-based mining tailings in treated seawater with reduced magnesium content. For the treatment, 0.06 M of lime was added to the liquor, generating solid magnesium complexes that were subsequently removed by vacuum filtration. Magnesium content [...] Read more.
A population balance model described the flocculation of clay-based mining tailings in treated seawater with reduced magnesium content. For the treatment, 0.06 M of lime was added to the liquor, generating solid magnesium complexes that were subsequently removed by vacuum filtration. Magnesium content varied between 10–1440 ppm when mixing raw seawater with treated seawater. The aggregate size was analysed by the Focused Beam Reflectance Measurement (FBRM) technology. The model follows the dynamics of the aggregation-rupture and it provides a good approximation to the temporal evolution. A decrease in collision efficiency was implemented as an indicator of the polymer depletion, describing the size reduction. Lower magnesium content makes larger aggregates with a higher fractal dimension, but an increase in the concentration of clays reduces both the size of aggregates and the fractal dimension, indicating more open and porous structures, with higher permeability to the passage of fluid. The model efficiently illustrates the experimental data, with R-square (R2) greater than 0.9 and Goodness of Fit (GoF) greater than 95% in most cases, wherein the fitting parameters allowed for analysing the impact of magnesium and clays on the collision efficiency, collision frequency, and fragmentation rate. The model is predictive with few parameters, and it is potentially a powerful tool for water management optimisation. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
Uranium (VI) Recovery from Black Shale Leaching Solutions Using Ion Exchange: Kinetics and Equilibrium Studies
Minerals 2020, 10(8), 689; https://doi.org/10.3390/min10080689 - 31 Jul 2020
Abstract
This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact [...] Read more.
This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact time at room temperature. These experiments addressed sorption kinetics and sorption isotherm. The maximum sorption capacity reached 55.8 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at initial uranium concentration of 0.62 mg·L−1. To describe sorption kinetics pseudo-first-order, pseudo-second-order and intraparticle diffusion models were proposed. Studies indicated that the sorption of uranium can be fitted by a pseudo-second-order kinetic model very well. Equilibria were described by Langmuir, Freundlich, and Dubinin–Radushkevich equations. The experimental sorption isotherm is successfully described by the Langmuir model. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
Yoko–Dovyren Layered Massif: Composition, Mineralization, Overburden and Dump Rock Utilization
Minerals 2020, 10(8), 682; https://doi.org/10.3390/min10080682 - 30 Jul 2020
Abstract
Ultramafic–mafic complexes are widely developed in the Earth’s crust. They contain deposits of various minerals. The Yoko–Dovyren intrusive in the North Baikal Region, Russia, is considered an example of an intrusive containing diverse mineralization: Ni-Cu, Platinum group elements, Cr, Zr, B, and blue [...] Read more.
Ultramafic–mafic complexes are widely developed in the Earth’s crust. They contain deposits of various minerals. The Yoko–Dovyren intrusive in the North Baikal Region, Russia, is considered an example of an intrusive containing diverse mineralization: Ni-Cu, Platinum group elements, Cr, Zr, B, and blue diopside. During the development of the deposit, a huge amount of magnesium-containing rocks are moved to dumps and have a negative impact on the environment. To minimize this process, overburden and host rocks need to be involved in production, thereby avoiding the movement of rocks into dumps. The construction materials production is main industry using this rocks. Therefore, the purpose of these studies was to determine the quality of magnesium-containing rocks and the possibility of their use in construction. As a result of the complex works performed, it has been determined that these rocks have required physical and mechanical characteristics. Concretes in large and small aggregates from magnesium-containing rocks were obtained. It has been concluded that they are superior to concrete from granite rubble and quartz sand in terms of their strength indicators. The use of magnesium-containing rocks, without allowing them to fall into dumps, will allow us to create clean, environmentally safe mining enterprises. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
Effect of Additive Material on Controlling Chromium (Cr) Leaching from Coal Fly Ash
Minerals 2020, 10(6), 563; https://doi.org/10.3390/min10060563 - 23 Jun 2020
Abstract
Coal fly ash contains a considerable number of toxic elements that can be leached into the environment, such as chromium (Cr), thereby quickly leading to severe contaminations. In this research, the leaching behaviors of Cr were analyzed from 14 kinds of coal fly [...] Read more.
Coal fly ash contains a considerable number of toxic elements that can be leached into the environment, such as chromium (Cr), thereby quickly leading to severe contaminations. In this research, the leaching behaviors of Cr were analyzed from 14 kinds of coal fly ash samples collected from the electrostatic precipitators of coal-fired thermal power plants in Japan. The level of Cr concentration found in the samples varied from 0.00 to 82.93 μg/L. However, Cr toxicity depends on its valence state; Cr6+ is more toxic than Cr3+. Additive materials containing high calcium content were used to control the leaching concentration of Cr, such as Ca(OH)2, paper sludge ash, and blast furnace cement. This research used several instruments. An X-ray fluorescence was adopted to measure the major chemical composition of the fly ash samples and the additive materials. A thermogravimetric analyzer was used to examine the calcium compounds in the additive materials. Inductively coupled plasma was used to determine the Cr leaching concentrations from the fly ash samples. Findings showed that the three-additive mixture had a promising effect on controlling the Cr leaching concentrations. These results were also supported by FactSage 7.2 simulation. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
Cleaner Production of Chromium Oxide from Low Fe(II)-Chromite
Minerals 2020, 10(5), 460; https://doi.org/10.3390/min10050460 - 19 May 2020
Cited by 1
Abstract
Sulfuric acid-based leaching is a promising cleaner method to produce chromium salts, but its feasibility for treating low Fe(II)-chromite still remains to be proven. A Box–Behnken design (BBD)-based set of experiments for sulfuric acid leaching of low Fe(II)-chromite was utilized in this work [...] Read more.
Sulfuric acid-based leaching is a promising cleaner method to produce chromium salts, but its feasibility for treating low Fe(II)-chromite still remains to be proven. A Box–Behnken design (BBD)-based set of experiments for sulfuric acid leaching of low Fe(II)-chromite was utilized in this work for generating an experimental dataset for revealing the functional relationships between the processing parameters and the extraction yields of Cr and Fe. The dependent variables were found to exhibit strong intercorrelations and the models developed on the basis of statistical criteria showed excellent prediction accuracy. The optimum process conditions of leaching treatment were found to be a temperature of 176 °C, a dichromic acid/chromite mass ratio of 0.12, and a sulfuric acid concentration of 81%. Furthermore, the dissolution behavior of chromite in the leaching process and the effect of dichromic acid were experimentally investigated. It was found that the decomposition efficiency was highly dependent on the Fe(II) content of chromite, and that the dichromic acid acted both as an oxidant and a catalyst in the leaching process. On the basis of the results of this study, a novel process for treating low-Fe(II) chromite was proposed. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
Analysis of Kaolin Flocculation in Seawater by Optical Backscattering Measurements: Effect of Flocculant Management and Liquor Conditions
Minerals 2020, 10(4), 317; https://doi.org/10.3390/min10040317 - 31 Mar 2020
Cited by 2
Abstract
Optical backscattering (OBS) signal values were used to evaluate the flocculation of kaolin slurries and seek the implications of using seawater. Two anionic flocculants were applied to kaolin suspensions at several dosages and in water of varying pH and electrolyte concentration. An OBS [...] Read more.
Optical backscattering (OBS) signal values were used to evaluate the flocculation of kaolin slurries and seek the implications of using seawater. Two anionic flocculants were applied to kaolin suspensions at several dosages and in water of varying pH and electrolyte concentration. An OBS height scan method was used to estimate the degree of aggregation, supernatant quality, and solids concentration of the sediments. The residual solids of the supernatant depended of the extent of particle coagulation before flocculant was added, where the pH and salinity displayed a significant impact on flocculation. The OBS results were highly sensitive to the presence of fine particles, which was estimated in parallel from the focused beam reflectance measurements (FBRM.) In seawater, without flocculant added, the samples had increased root-mean-square scattering (Frms) values and larger final sediment volume than samples prepared in water with lower electrolyte concentration. This indicates a higher initial state of aggregation of the particles in seawater. Then, the aggregation degree was best linked to the square-weighted chord length distribution of the FBRM data, which intensifies the sensitivity to coarse aggregates. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
The Role of Gangue Mineralogy on Flowsheet Development in Fluorite Processing
Minerals 2020, 10(3), 237; https://doi.org/10.3390/min10030237 - 06 Mar 2020
Abstract
Fluorite, CaF2, is considered a strategically important mineral as it is a raw material for many strategic industries. Froth flotation is reported to be the most efficient and economically viable process for the production of an acid-grade product with a CaF [...] Read more.
Fluorite, CaF2, is considered a strategically important mineral as it is a raw material for many strategic industries. Froth flotation is reported to be the most efficient and economically viable process for the production of an acid-grade product with a CaF2 content of at least 97%. Selective flotation of fluorite from gangue minerals, e.g., calcite and barite, is challenging because these minerals have similar physicochemical properties. This study employed batch flotation tests coupled with mineralogical analysis to design suitable customised flowsheets and efficiently optimised reagent regimes for optimum production of acid-grade fluorite concentrate from two different fluorite ores by the froth flotation process. The effect of pulp temperature on fluorite flotation was investigated in this study with the objective of lowering pulp temperatures in fluorite flotation. The results showed that an acid-grade CaF2 concentrate could be obtained from the flotation of both ores at ambient pulp temperatures. This eliminates the requirement for high-temperature pulp treatment, which would result in a significant reduction in thermal energy costs. This study showed that an understanding of gangue mineralogy is key to process optimisation for acid-grade CaF2 production. Although an acid-grade CaF2 concentrate could be produced from both ores, the flowsheets and reagent regimes were markedly different. For instance, the production of an acid-grade CaF2 product from a high quartz and calcite ore was achieved by employing a simple rougher–multiple cleaner flotation circuit using tannin and sodium silicate as calcite and quartz depressants, respectively. On the other hand, the production of an acid-grade CaF2 product from the flotation of the pyritic ore required a pre-sulphide flotation stage for upfront sulphur removal and the use of a sulphide depressant. Multiple stages of cleaning were required for improved selectivity in the flotation of both ores. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
Extraction of Boron from Ludwigite Ore: Mechanism of Soda-Ash Roasting of Lizardite and Szaibelyite
Minerals 2019, 9(9), 533; https://doi.org/10.3390/min9090533 - 31 Aug 2019
Cited by 3
Abstract
Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, [...] Read more.
Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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Open AccessArticle
A Clean Process to Prepare High-Quality Acid-Soluble Titanium Slag from Titanium Middling Ore
Minerals 2019, 9(8), 460; https://doi.org/10.3390/min9080460 - 27 Jul 2019
Cited by 3
Abstract
A direct reduction-magnetic separation-alkali leaching-dilute acid washing method was proposed to prepare high-quality acid-soluble titanium slag (HQASTS) from titanium middling ore. The relevant potential pH diagrams were built, and the analysis results showed that the pH values for alkali leaching and dilute acid [...] Read more.
A direct reduction-magnetic separation-alkali leaching-dilute acid washing method was proposed to prepare high-quality acid-soluble titanium slag (HQASTS) from titanium middling ore. The relevant potential pH diagrams were built, and the analysis results showed that the pH values for alkali leaching and dilute acid washing should be higher than 13.50 and lower than 1.00, respectively. Increasing temperature was beneficial to alkali leaching but not to dilute acid washing. The effects of operating parameters on the TiO2 content and impurity oxides extraction ratios of titanium slag were investigated, and the optimal experimental conditions were obtained. The HQASTS was obtained with TiO2 and Fe2O3 content of 75.37 wt % and 0.96 wt %, respectively, under the above conditions. Furthermore, the leaching mechanism was studied by chemical analysis and X-ray diffraction (XRD) technology, and it was found that the alkali leaching-dilute acid washing process presented in this work could avoid the encapsulation of the unreacted anorthite by the calcium aluminum spinel generated in alkali leaching. Full article
(This article belongs to the Special Issue Cleaner Production in Mineral Processing)
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