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Challenges in the Development of Sustainable Extractive Metallurgy Processes

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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: closed (31 October 2020) | Viewed by 36643

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Special Issue Editors

Prof. Dr. Alexandre Chagnes

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Guest Editor

GeoRessources, Université de Lorraine, CNRS, 54000 Nancy, France
Interests: hydrometallurgy; lithium-ion battery; solvent extraction; recycling; circular economy
Special Issues, Collections and Topics in MDPI journals

Dr. Aleksandra Rybak

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Guest Editor

Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, 44-100 Gliwice, Poland
Interests: element speciation analysis; environmental protection; inorganic chemistry; metal recovery from industrial wastes; REEs; hybrid inorganic-organic membranes; membrane separation
Special Issues, Collections and Topics in MDPI journals

Dr. Aurelia Rybak

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Guest Editor

Department of Electrical Engineering and Industrial Automation, Faculty of Mining, Safety Engineering and Industrial Automation, Silesian University of Technology, 44-100 Gliwice, Poland
Interests: membrane technology; environmental protection; metal recovery from industrial wastes; REEs; trade
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The development of new technologies and the increasing demand of mineral resources from emerging countries are responsible for significant tensions on the price of nonferrous metals. Some metals become strategic and critical because they are used in many technological applications, and their availability remains limited. In addition to energetic raw materials like oil or gas, the industry uses about fifty different metals. For many of them, the worldwide annual consumption ranges from a few tens of tons to several hundred thousand tons. Some of them, the so-called strategic metals, are crucial for achieving high performances. They are found in high-tech products such as flat panel TVs (indium), solar panel cells (indium), lithium–ion batteries for electric vehicles (lithium), magnets (rare earths such as neodymium and dysprosium), scintillators (rare earths), and aviation and medical applications (titanium). The secured supply of these metals is crucial to continue producing and exporting their technologies and because specific properties of these metals make them essential and difficult to substitute for a given industrial application.

Many challenges have to be addressed to ensure a sustainable supply of raw materials for our industries. These challenges are not only related to technology but also societal and territory aspects. Two routes can be implemented to recover metals from primary (mining) and secondary (recycling, residues) resources: pyrometallurgy and hydrometallurgy. A third route consists in combining pyrometallurgical and hydrometallurgical operations in a unique process in order to take advantage of both approaches. In all cases, these processes must be efficient, cheap while keeping an as low as possible CAPEX and OPEX.

This Special Issue aims at gathering recent advances in the field of extractive metallurgy applied to metal valorization contained in primary and secondary resources and to the development of technologies aiming at reducing effluent production and effluent impact on environment. Recent studies on societal and environmental impacts of extractive metallurgy as well as economics of processes are also of interest for this Special Issue.

Prof. Alexandre Chagnes
Dr. Aleksandra Rybak
Dr. Aurelia Rybak
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

extractive metallurgy
mining
recycling
residues
effluent
environmental impact
economics
societal impact
processes

Published Papers (7 papers)

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Research

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10 pages, 3787 KiB

Open AccessArticle

Effect of Pre-Treatment with Sodium Chloride/Sulfuric Acid on the Bornite Concentrate Leaching in Chloride Medium

by Patricio Navarro, Cristian Vargas, Fabiana Bahamonde, Matías Gómez, Daniel Espinoza, Rossana Sepúlveda and Jonathan Castillo

Metals 2020, 10(12), 1674; https://doi.org/10.3390/met10121674 - 14 Dec 2020

Cited by 2 | Viewed by 2397

Abstract

In this work, the effect of the pre-treatment of bornite concentrate with a sodium chloride–sulfuric acid mixture prior to leaching with chloride solutions was evaluated. The influence of the dosage of NaCl and the resting time in the copper solution was evaluated. The solid residues of the pre-treatment were characterized by XRD to evaluate the changes that took place in the bornite. The experimental results show that as the sitting time and the amount of sodium chloride added are increased, the dissolution of the sulfide species also increased. The pre-treatment affects Cu preferentially because it has greater mobility than iron in the bornite crystal lattice. The pre-treatment promotes the formation of soluble Cu and Fe species. The efficiency of the pre-treatment depends largely on the formation of hydrochloric acid in the mixture at the particle level, due to the ease with which it diffuses through the bornite particles, achieving greater penetration of the pre-treatment. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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21 pages, 5142 KiB

Open AccessArticle

Fe(III) Precipitation and Copper Loss from Sulphate-Chloride Solutions at 150 °C: A Statistical Approach

by Tasawar Javed and Edouard Asselin

Metals 2020, 10(5), 669; https://doi.org/10.3390/met10050669 - 20 May 2020

Cited by 3 | Viewed by 2475

Abstract

The purification of hydrometallurgical process solutions by Fe(III) precipitation is a common and large-scale industrial operation. This step is notorious for valuable metal loss occurring with the iron precipitation product, which is usually directed to tailings. In this study, factors affecting Fe(III) precipitation and associated copper loss were studied in synthetic process solutions using statistical methods. The variables studied were: Initial acid concentration, retention time, seed addition, and initial Fe(III), Cu(II), and chloride concentrations. The importance of each variable and its interaction effects were studied against two responses, i.e., percent of Fe(III) precipitated as hematite and percent of Cu lost to solids. The results showed that a combination of high acid and moderate seeding was required to simultaneously achieve high proportions of Fe(III) precipitated as hematite and lower copper loss to the precipitates. High acid concentrations create low supersaturation for Fe(III), which minimizes the consequences of homogeneous nucleation and favors particle growth. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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12 pages, 3348 KiB

Open AccessFeature PaperArticle

Recovery of Metal Values from Ni-Cd Cake Waste Residue of an Iranian Zinc Plant by Hydrometallurgical Route

by Sushanta Kumar Sahu, Maryam Kargar Razi, Mathieu Beuscher and Alexandre Chagnes

Metals 2020, 10(5), 655; https://doi.org/10.3390/met10050655 - 19 May 2020

Cited by 5 | Viewed by 3958

Abstract

This paper concerns the development of an environment-friendly hydrometallurgical flowsheet dedicated to the recovery of zinc and nickel from a waste residue collected from an Iranian zinc plant. In particular, valuable metals from Ni-Cd cake waste generated at this plant were recovered by a simple hydrometallurgical process using minimum acid for leaching, and solvent extraction step was designed such that addition of sodium hydroxide was not required and the effluent generated is safe to dispose off. The waste was leached with a mixture of hydrochloric acid and sulfuric acid in the presence of hydrogen peroxide in order to achieve a good selectivity towards iron and calcium. Afterwards, cementation was performed at pH 5 in order to remove cadmium. Liquid–liquid extraction was then implemented to produce high-purity solutions of zinc and nickel. Zinc-nickel separation was obtained at pH 2 by using a mixture of bis-(2-ehtyl-hexyl)-phosphoric acid (HDEHP) and tris-2-ethylhexyl amine (TEHA) diluted in an aliphatic kerosene. TEHA did not directly participate but helped in the extraction of zinc by scavenging the protons released by HDEHP. Therefore, no alkaline solution was necessary for maintaining the equilibrium pH during liquid–liquid extraction. Finally, this flowsheet allowed to recover more than 95% of zinc and nickel from the residue with more than 99% purity. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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9 pages, 2228 KiB

Open AccessArticle

Tantalum Recycling by Solvent Extraction: Chloride Is Better than Fluoride

by Luke M. M. Kinsman, Rosa A. M. Crevecoeur, Amrita Singh-Morgan, Bryne T. Ngwenya, Carole A. Morrison and Jason B. Love

Metals 2020, 10(3), 346; https://doi.org/10.3390/met10030346 - 6 Mar 2020

Cited by 16 | Viewed by 4788

Abstract

The recycling of tantalum (Ta) is becoming increasingly important due to the criticality of its supply from a conflict mineral. It is used extensively in modern electronics, such as in capacitors, and so electronic waste is a potentially valuable secondary source of this metal. However, the recycling of Ta is difficult, not least because of the challenges of its leaching and subsequent separation from other metals. In this work, we show that Ta(V) halides, such as TaCl₅ and TaF₅, which can potentially be accessed from Ta metal upon acid halide leaching, can be recovered by solvent extraction using a simple primary amide reagent. The need for high halide concentrations in the aqueous phase implies the formation of the hexahalide salts [TaX₆]⁻ (X = F, Cl) and that an anion-swing mechanism operates. While extraction of the fluorides is poor (up to 45%), excellent extraction under chloride conditions is found (>99%) and presents an alternative route to Ta recycling. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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Review

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28 pages, 1328 KiB

Open AccessReview

Characteristics of Some Selected Methods of Rare Earth Elements Recovery from Coal Fly Ashes

by Aleksandra Rybak and Aurelia Rybak

Metals 2021, 11(1), 142; https://doi.org/10.3390/met11010142 - 12 Jan 2021

Cited by 38 | Viewed by 4326

Abstract

The article covers the issues related to the characteristics, application, and some methods of rare earth elements (REEs) recovery from coal fly ashes. REEs are elements with growing demand and a very wide range of application, especially when it comes to modern technologies. The conducted analysis and price forecast proved the existing upward tendency, and this confirmed the need to search for new REE sources, among industrial waste (proecological effect). The development of the REE recovery technology would involve solving several problems related to REE speciation, optimization of factors controlling their extractivity and selection of the REE separation method from obtained extraction solutions with a very extreme pH and complicated composition. The paper presented advantages and disadvantages of usually used methods of REE separation from coal fly ashes, like physical and acid–base leaching. It was also presented alternative REE recovery techniques in the form of membrane and biological methods and based on ion liquids (ILs) or chelating agents. The directions of further modifications, which will allow the efficient REE recovery were presented. The aim of this article was to propose specific solutions based on the creation of appropriate multistage method of REE recovery. It will be a combination of magnetic and size separation, acid–base leaching (including roasting in justified cases), removal of matrix elements with ILs (Al, Si, and Fe), and finally REE membrane separation, allowing one to obtain the appropriate process efficiency. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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16 pages, 3675 KiB

Open AccessReview

Precipitation and Crystallization Used in the Production of Metal Salts for Li-Ion Battery Materials: A Review

by Yiqian Ma, Michael Svärd, Xiong Xiao, James M. Gardner, Richard T. Olsson and Kerstin Forsberg

Metals 2020, 10(12), 1609; https://doi.org/10.3390/met10121609 - 30 Nov 2020

Cited by 25 | Viewed by 9534

Abstract

Li-ion battery materials have been widely studied over the past decades. The metal salts that serve as starting materials for cathode and production, including Li₂CO₃, NiSO₄, CoSO₄ and MnSO₄, are mainly produced using hydrometallurgical processes. In hydrometallurgy, aqueous precipitation and crystallization are important unit operations. Precipitation is mainly used in the processes of impurity removal, separation and preliminary production, while controlled crystallization can be very important to produce a pure product that separates well from the liquid solution. Precipitation and crystallization are often considered in the development of sustainable technologies, and there is still room for applying novel techniques. This review focuses on precipitation and crystallization applied to the production of metal salts for Li-ion battery materials. A number of novel and promising precipitation and crystallization methods, including eutectic freeze crystallization, antisolvent crystallization, and homogeneous precipitation are discussed. Finally, the application of precipitation and crystallization techniques in hydrometallurgical recycling processes for Li-ion batteries are reviewed. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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18 pages, 4969 KiB

Open AccessFeature PaperReview

Literature Review and Thermodynamic Modelling of Roasting Processes for Lithium Extraction from Spodumene

by Allen Yushark Fosu, Ndue Kanari, James Vaughan and Alexandre Chagnes

Metals 2020, 10(10), 1312; https://doi.org/10.3390/met10101312 - 30 Sep 2020

Cited by 20 | Viewed by 7414

Abstract

This review adds to the public domain literature on the extraction of lithium from mineral ores. The focus is on the pyrometallurgical pre-treatment of spodumene. Information on the phase transformation from α to β, the heat treatment methods as well as the behavior of various compounds in the roasting processes are evaluated. Insight into the chemical thermodynamics of the baking process is evaluated using HSC Chemistry software up to 1200 °C. It was observed that the alkaline, sulfation, chlorination (using Cl₂ and CaCl₂), carbonizing (to form Li₂CO₃) and fluorination processes were feasible either throughout or at a point within the temperature range considered. Chlorination using KCl and carbonizing to form Li₂O are the processes found to be nonspontaneous throughout the temperatures considered. Full article

(This article belongs to the Special Issue Challenges in the Development of Sustainable Extractive Metallurgy Processes)

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