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Toward Achieving a Carbon-Neutral Society: Beneficiation and Extractive Metallurgy for Producing Critical Metals from Ores/Wastes

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A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Extractive Metallurgy".

Deadline for manuscript submissions: 31 August 2024 | Viewed by 4053

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Special Issue Editors

Dr. Ilhwan Park

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Guest Editor

Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, Sapporo 060-0808, Japan
Interests: mineral processing; flotation; hydrometallurgy; leaching; electrochemistry; resource recycling; environmental remediation; acid mine drainage; sulfide passivation
Special Issues, Collections and Topics in MDPI journals

Dr. Sanghee Jeon

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Guest Editor

Graduate School of Engineering and Resource Science, Akita University, Akita 010-0865, Japan
Interests: mineral processing; hydrometallurgy; resource recycling; leaching; cementation; electrochemistry

Special Issue Information

Dear Colleagues,

The global climate change crisis has become a major issue in recent years, and it has forced us to pursue carbon neutrality as our common, primary, and initiative goal. For this, more than 130 countries have set or considering setting a target of reducing the greenhouse gas (GHG) emissions to net-zero by 2050 by replacing fossil-fuel-based energy and transportation systems to low-carbon technologies (e.g., renewable energy, hydrogen energy, electric vehicles (EVs), etc.). However, these technologies require vast amounts of metals per unit generation compared to that of conventional fossil generation. Thus, the sustainable production of metals critical to a low carbon future (e.g., aluminum, cobalt, copper, lithium, nickel, platinum group metals (PGMs), rare earth metals (REMs), silver, vanadium, etc.) is of topical importance to combat CO₂-induced climate change.

In this Special Issue, we invite articles that focus on recent advances in beneficiation (e.g., gravity separation, magnetic separation, flotation, etc.) and extractive metallurgy (e.g., atmospheric leaching, bioleaching, pressure leaching, solvometallurgy, etc.) for producing critical metals from primary, as well as secondary resources, such as tailings, metallurgical residues, slags, E-wastes, or wastewater. We welcome not only research papers but also review papers, short communications, and case reports.

Dr. Ilhwan Park
Dr. Sanghee Jeon
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. Metals 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 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

carbon-neutrality
critical metals
beneficiation
gravity separation
magnetic separation
flotation
extractive metallurgy
leaching
solvent extraction
cementation
adsorption
precipitation
primary/secondary resources

Related Special Issue

Advances in Selective Flotation and Leaching Process in Metallurgy in Metals (12 articles)

Published Papers (3 papers)

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Research

18 pages, 13118 KiB

Open AccessArticle

Microwave Treatment of Copper–Nickel Sulfide Ore for Promotion of Grinding and Flotation

by Xiaolei Fang, Zhiwei Peng, Tianle Yin, Mingjun Rao and Guanghui Li

Metals 2024, 14(5), 565; https://doi.org/10.3390/met14050565 (registering DOI) - 11 May 2024

Viewed by 85

Abstract

The effect of microwave treatment on the grinding and flotation performance of a typical copper–nickel sulfide ore was evaluated, based on the determination of its microwave absorption capability, grinding and flotation indexes such as crack percentage, mineral liberation degree, particle size distribution, relative work index (RWI), metal enrichment ratio, and recovery. There were obvious differences between the microwave absorption capabilities of the main minerals in the ore, as demonstrated by their different microwave penetration depths. They also induced temperature differences between sulfide minerals and gangue minerals which could reach 418 °C after microwave treatment for 20 s. It was shown that microwave treatment could effectively improve the grindability of the ore, as proven by the increase in fine particles smaller than 0.074 mm and a decrease in RWI after grinding due to the higher crack percentage and mineral liberation degree. Moreover, microwave treatment affected the ore floatability because of the generation of cuprite, retgersite, and rozenite with poor floatability when the treatment time was extended. By microwave treatment for a proper time, 20 s, an optimal balance between the grindability and flotation performance could be achieved. Compared with the untreated ore, the RWI of the ore decreased by 11.5%. After flotation, the Cu and Ni enrichment ratios of the flotation concentrate increased by 0.3 and 0.2, respectively. Meanwhile, their corresponding recoveries increased by 4.2% and 3.1%. This study provides new insights for the treatment of copper–nickel sulfide ore to enhance the grinding and flotation process. Full article

(This article belongs to the Special Issue Toward Achieving a Carbon-Neutral Society: Beneficiation and Extractive Metallurgy for Producing Critical Metals from Ores/Wastes)

19 pages, 6671 KiB

Open AccessFeature PaperArticle

A Pretreatment of Refractory Gold Ores Containing Sulfide Minerals to Improve Gold Leaching by Ammonium Thiosulfate: A Model Experiment Using Gold Powder and Arsenic-Bearing Sulfide Minerals

by Takunda Joseph Mhandu, Ilhwan Park, Sanghee Jeon, Sohta Hamatsu, Yogarajah Elakneswaran, Mayumi Ito and Naoki Hiroyoshi

Metals 2023, 13(8), 1357; https://doi.org/10.3390/met13081357 - 28 Jul 2023

Cited by 1 | Viewed by 1944

Abstract

The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant. In this study, a new method to improve gold extraction from sulfide bearing gold ores is proposed based on the model experiments using a mixture of gold powder and arsenopyrite-bearing sulfide (HAsBS) ore. The effects of HAsBS ore on gold leaching in ammonium thiosulfate solutions were investigated, and it was found that gold extraction in the presence of HAsBS ore was suppressed because of the unwanted decomposition of thiosulfate on the surface of sulfide minerals. To improve gold extraction in the presence of the sulfide minerals, this study investigated the effects of the pretreatment of HAsBS ore using ammonium solutions containing cupric ions and confirmed that HAsBS ore was oxidized in the pretreatment and its surface was covered by the oxidation products. As a result, thiosulfate consumption was minimized in the subsequent gold leaching step using ammonium thiosulfate, resulting in an improvement in gold extraction from 10% to 79%. Full article

(This article belongs to the Special Issue Toward Achieving a Carbon-Neutral Society: Beneficiation and Extractive Metallurgy for Producing Critical Metals from Ores/Wastes)

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18 pages, 4113 KiB

Open AccessArticle

Selective Cementation of Gold Using an Iron Oxide and Zero-Valent Aluminum Galvanic System from Gold–Copper Ammoniacal Thiosulfate Solutions

by Joshua Zoleta, Sanghee Jeon, Akuru Kuze, Nako Okada, Ilhwan Park, Mayumi Ito, Yogarajah Elakneswaran and Naoki Hiroyoshi

Metals 2023, 13(7), 1289; https://doi.org/10.3390/met13071289 - 18 Jul 2023

Viewed by 1440

Abstract

Ammonium thiosulfate leaching is a promising alternative to the conventional cyanide method for extracting gold from ores. However, strategies for recovering gold from the leachate are less commercially used due to its low affinity to gold. The present study investigated the recovery of gold from the leachate using iron oxides (hematite, Fe₂O₃ or magnetite, Fe₃O₄). Cementation experiments were conducted by mixing 0.15 g of aluminum powder as an electron donor and 0.15 g of an electron mediator (activated carbon, hematite, or magnetite) in 10 mL of ammonium thiosulfate leachate containing 100 mg/L gold ions and 10 mM cupric ions for 24 h at 25 °C. The results of the solution analysis showed that when activated carbon (AC) was used, the gold was recovered together with copper (recoveries were 99.99% for gold and copper). However, selective gold recovery was observed when iron oxides were used, where the gold and copper recoveries were 89.7% and 21% for hematite and 85.9% and 15.4% for magnetite, respectively. An electrochemical experiment was also conducted to determine the galvanic interaction between the electron donor and electron mediator in a conventional electrochemical setup (hematite/magnetite–Al as the working electrode, Pt as the counter electrode, Ag/AgCl as the reference electrode) in a gold–thiosulfate medium. Cyclic voltammetry showed a gold reduction “shoulder-like” peak at −1.0 V using hematite/Al and magnetite/Al electrodes. Chronoamperometry was conducted and operated at a constant voltage (−1.0 V) determined during cyclic voltammetry and further analyzed using SEM-EDX. The results of the SEM-EDX analysis for the cementation products and electrochemical experiments confirmed that the gold was selectively deposited on the iron oxide surface as an electron mediator. Full article

(This article belongs to the Special Issue Toward Achieving a Carbon-Neutral Society: Beneficiation and Extractive Metallurgy for Producing Critical Metals from Ores/Wastes)

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