Special Issue "Advances in Hydrometallurgy"

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (30 September 2018).

Special Issue Editor

Prof. Alexandre Chagnes
E-Mail Website
Guest Editor
University of Lorraine, GeoRessources Lab, UMR CNRS 7359, 2 Rue Doyen Marcel Roubault, TSA 70605, F-54518 Vandoeuvre Les Nancy, France
Interests: hydrometallurgy; electrochemistry of lithium–ion batteries; solution chemistry; recycling
Special Issues and Collections 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 in the price of non-ferrous metals. Some metals have become strategic and critical because they are used in many technological applications and their availability remains limited. In addition to energetic raw materials, such as 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 these technologies, and because specific properties of these metals make them essential and difficult to substitute for a given industrial application.

Hydrometallurgical processes have the advantages of being able to process low-grade ores, to allow better control of co-products and to have a lower environmental impact. With the depletion of deposits and the growing interest in low-grade elements (e.g., rare earth elements), the metallurgical industry has shown a growing interest in the development of hydrometallurgical processes more adapted to current challenges over the last fifteen years. The need to develop more efficient, economical and environmentally-friendly processes, capable of extracting metals from increasingly complex and poorly polymetallic matrices, is real. The aim of this Special Issue is to highlight recent advances related to hydrometallurgy to face new challenges in metal production.

Prof. Alexandre Chagnes
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 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. 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 1500 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

  • Raw material
  • Extractive metallurgy
  • Hydrometallurgy
  • Process
  • Strategic metals
  • Critical metals
  • Recycling
  • Physicochemistry

Published Papers (13 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Editorial

Jump to: Research, Review

Open AccessEditorial
Advances in Hydrometallurgy
Metals 2019, 9(2), 211; https://doi.org/10.3390/met9020211 - 11 Feb 2019
Abstract
The development of new technologies and the increasing demand of mineral resources from emerging countries are responsible for significant tensions in the price of non-ferrous metals [...] Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)

Research

Jump to: Editorial, Review

Open AccessArticle
Electrochemical Behaviour of Chalcopyrite in Chloride Solutions
Metals 2019, 9(1), 67; https://doi.org/10.3390/met9010067 - 11 Jan 2019
Abstract
Due to the depletion of oxidized copper ores, it necessitates the need to focus on metallurgical studies regarding sulphide copper ores, such as chalcopyrite. In this research, the electrochemical behaviour of chalcopyrite has been analysed under different conditions in order to identify the [...] Read more.
Due to the depletion of oxidized copper ores, it necessitates the need to focus on metallurgical studies regarding sulphide copper ores, such as chalcopyrite. In this research, the electrochemical behaviour of chalcopyrite has been analysed under different conditions in order to identify the parameters necessary to increase the leaching rates. This was carried out through cyclic voltammetry tests at 1 mV/s using a pure chalcopyrite macro-electrode to evaluate the effect of scan rate, temperature, and the addition of chloride, cupric, and ferrous ions. Lastly, the feasibility of using seawater for chalcopyrite dissolution was investigated. An increase in the sweep rate and temperature proved to be beneficial in obtaining highest current densities at 10 mV/s and 50 °C. Further, an increase of chloride ions enhanced the current density values. The maximum current density obtained was 0.05 A/m2 at concentrations of 150 g/L of chloride. An increase in the concentration of cupric ions favoured the oxidation reaction of Fe (II) to Fe (III). Finally, the concentration of chloride ions present in seawater has been identified as favourable for chalcopyrite leaching. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Europium, Yttrium, and Indium Recovery from Electronic Wastes
Metals 2018, 8(10), 777; https://doi.org/10.3390/met8100777 - 29 Sep 2018
Cited by 1
Abstract
Waste electrical and electronic equipment (WEEE) has increased in recent decades due to the continuous advancement of technology in the modern world. These residues have various metals that are found in concentrations that make their recovery profitable. A group of metals of interest [...] Read more.
Waste electrical and electronic equipment (WEEE) has increased in recent decades due to the continuous advancement of technology in the modern world. These residues have various metals that are found in concentrations that make their recovery profitable. A group of metals of interest are the rare earths such as europium and yttrium, as well as semiconductors such as indium. Yttrium was recovered from cathode ray tubes that were manually dismantled. The resulted powder was leached with HNO3, and then the solution was submitted to solvent extraction with di-(2-ethylhexyl) phosphoric acid (DEHPA) using n-heptane as a diluent. For re-extraction, HNO3 was used again, and yttrium was precipitated by adding four times the stoichiometric amount of oxalic acid, reaching 68% yttrium purity. Indium was recovered from the liquid crystal display (LCD) screens for which the pulverized material was leached with H2SO4. Then, the indium sulfate was subjected to solvent extraction using DEHPA as an extractant, and diesel as a diluent. The re-extraction was carried out again with H2SO4, and the obtained acid solution was evaporated until the indium precipitated, reaching a recovery of 95%. The investigations that were carried out show that it is feasible to recover these metals in the form of oxides or phosphates with high commercial value. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Selective Extraction of Rare Earth Elements from Phosphoric Acid by Ion Exchange Resins
Metals 2018, 8(9), 682; https://doi.org/10.3390/met8090682 - 30 Aug 2018
Cited by 1
Abstract
Rare earth elements (REE) are present at low concentrations (hundreds of ppm) in phosphoric acid solutions produced by the leaching of phosphate ores by sulfuric acid. The strongly acidic and complexing nature of this medium, as well as the presence of metallic impurities [...] Read more.
Rare earth elements (REE) are present at low concentrations (hundreds of ppm) in phosphoric acid solutions produced by the leaching of phosphate ores by sulfuric acid. The strongly acidic and complexing nature of this medium, as well as the presence of metallic impurities (including iron and uranium), require the development of a particularly cost effective process for the selective recovery of REE. Compared to the classical but costly solvent extraction, liquid-solid extraction using commercial chelating ion exchange resins could be an interesting alternative. Among the different resins tested in this paper (Tulsion CH-93, Purolite S940, Amberlite IRC-747, Lewatit TP-260, Lewatit VP OC 1026, Monophos, Diphonix,) the aminophosphonic IRC-747, and aminomethylphosphonic TP-260 are the most promising. Both of them present similar performances in terms of maximum sorption capacity estimated to be 1.8 meq/g dry resin and in adsorption kinetics, which appears to be best explained by a moving boundary model controlled by particle diffusion. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Recovery of Metals from Secondary Raw Materials by Coupled Electroleaching and Electrodeposition in Aqueous or Ionic Liquid Media
Metals 2018, 8(7), 556; https://doi.org/10.3390/met8070556 - 20 Jul 2018
Abstract
This paper presents recent views on a hybrid process for beneficiation of secondary raw materials by combined electroleaching of targeted metals and electrodeposition. On the basis of several case studies with aqueous solutions or in ionic liquid media, the paper describes the potential [...] Read more.
This paper presents recent views on a hybrid process for beneficiation of secondary raw materials by combined electroleaching of targeted metals and electrodeposition. On the basis of several case studies with aqueous solutions or in ionic liquid media, the paper describes the potential and the limits of the novel, hybrid technique, together with the methodology employed, combining determination of speciation, physical chemistry, electrochemistry, and chemical engineering. On one hand, the case of electroleaching/electrodeposition (E/E) process in aqueous media, although often investigated at the bench scale, appears nevertheless relatively mature, because of the developed methodology, and the appreciable current density allowed, and so it can be used to successfully treat electrode materials of spent Zn/MnO2 batteries or Ni/Cd accumulators and Waelz oxide. On the other hand, the use of ionic liquids as promising media for the recovery of various metals can be considered for other types of wastes, as shown here for the case of electrodes of aged fuel cells. The combined (E/E) technique could be successfully used for the above waste, in particular by the tricky selection of ionic liquid media. Nevertheless, further investigations in physical chemistry and chemical engineering appear necessary for possible developments of larger-scale processes for the recovery of these strategic resources. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Novel Task Specific Ionic Liquids to Remove Heavy Metals from Aqueous Effluents
Metals 2018, 8(6), 412; https://doi.org/10.3390/met8060412 - 02 Jun 2018
Cited by 4
Abstract
Task Specific Ionic Liquids (ILs) were generated by association between a cationic ester derivative of betaine and coordinating inorganic anions such as dicyanamide (Dca), chlorosalycilate (ClSal) and saccharinate (sac). Extraction of Cu(II), Ni(II), Co.(II), Pb(II) and Cd(II) from water was performed [...] Read more.
Task Specific Ionic Liquids (ILs) were generated by association between a cationic ester derivative of betaine and coordinating inorganic anions such as dicyanamide (Dca), chlorosalycilate (ClSal) and saccharinate (sac). Extraction of Cu(II), Ni(II), Co.(II), Pb(II) and Cd(II) from water was performed with these ILs at room temperature. Our results show that ionic liquid with Clsal anions have a high extraction efficiency towards Cu(II), Ni(II), Cd(II), and Pb(II), whereas dicyanamide ionic liquid may extract efficiently Cu(II), Ni(II) Co.(II) and Cd(II). Ionic liquids with saccharinate anions are selective of Cd(II) ions. The extraction mechanism has been studied by the determination of the coextraction of the counter ion of the metal salt. Our results show that the extraction mechanism proceeds via a mixed process involving both cation exchange and ion-pairing. The proportion of which depends on the nature of the cation. The coordination of Cu(II), Ni(II) and Co.(II) in ionic liquid phase was followed by UV-vis spectroscopies. The metal could be back-extracted from the ionic liquid phase with aqueous EDTA solutions. The metal extractability of the ionic liquid after the back-extraction is equivalent to that of the fresh mixture showing that ionic liquid can be reused for several extraction and back-extraction cycles. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Graphical abstract

Open AccessArticle
Effect of Aqueous Media on the Recovery of Scandium by Selective Precipitation
Metals 2018, 8(5), 314; https://doi.org/10.3390/met8050314 - 03 May 2018
Cited by 6
Abstract
This research presents a novel precipitation method for scandium (Sc) concentrate refining from bauxite residue leachates and the effect of aqueous media on this triple-stage successive precipitation process. The precipitation pattern and the precipitation behavior of the constituent elements was investigated using different [...] Read more.
This research presents a novel precipitation method for scandium (Sc) concentrate refining from bauxite residue leachates and the effect of aqueous media on this triple-stage successive precipitation process. The precipitation pattern and the precipitation behavior of the constituent elements was investigated using different precipitation agents in three major mineral acid media, namely, H2SO4, HNO3, and HCl in a comparative manner. Experimental investigations showed behavioral similarities between HNO3 and HCl media, while H2SO4 media was different from them because of the nature of the formed complexes. NH4OH was found to be the best precipitation agent in every leaching media to remove Fe(III) with low Sc co-precipitation. To limit Sc loss from the system, Fe(III) removal was divided into two steps, leading to more than 90% of Fe(III) removal at the end of the process. Phosphate concentrates were produced in the final step of the precipitation process with dibasic phosphates which have a strong affinity towards Sc. Concentrates containing more than 50% of ScPO4 were produced in each case from the solutions after Fe(III) removal, as described. A flow diagram of the selective precipitation process is proposed for these three mineral acid media with their characteristic parameters. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Intensification Behavior of Mercury Ions on Gold Cyanide Leaching
Metals 2018, 8(1), 80; https://doi.org/10.3390/met8010080 - 21 Jan 2018
Cited by 2
Abstract
Cyanidation is the main method used to extract gold from gold raw materials; however, a serious problem with this method is the low leaching rate. In order to improve gold leaching, the intensification behavior of mercury ions on gold cyanide leaching, for two [...] Read more.
Cyanidation is the main method used to extract gold from gold raw materials; however, a serious problem with this method is the low leaching rate. In order to improve gold leaching, the intensification behavior of mercury ions on gold cyanide leaching, for two types of materials, sulphide gold concentrate and oxide gold ore, was investigated. The results showed that mercury ions, with only a 10−5 M dosage, could significantly intensify leaching and gold recovery. The dissolution behavior of gold plate was also intensified by 10−5 M mercury ions. Microstructure analysis showed that mercury ions intensified the cyanidation corrosion of the gold surface, resulting in a loose structure, where a large number of deep ravines and raised particles were evident across the whole gold surface. The loose structure added contact surface between the gold and cyanide, and accelerated gold dissolution. Moreover, mercury ions obstructed the formation of insoluble products, such as AuCN, Au(OHCN), and Au(OH)x, that lead to a passivation membrane on the gold surface, reducing contact between the gold and cyanide. These effects, brought about by mercury ions, change the structure and product of the gold surface during gold cyanidation and promote gold leaching. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Chemical Degradation of a Mixture of tri-n-Octylamine and 1-Tridecanol in the Presence of Chromium(VI) in Acidic Sulfate Media
Metals 2018, 8(1), 57; https://doi.org/10.3390/met8010057 - 15 Jan 2018
Cited by 1
Abstract
The chemical degradation of an extraction solvent composed of a mixture of tri-n-octylamine (extractant) and 1-tridecanol (phase modifier) in n-dodecane in contact with an acidic aqueous sulfate solution containing chromium(VI) has been investigated. The kinetics of degradation and the degradation [...] Read more.
The chemical degradation of an extraction solvent composed of a mixture of tri-n-octylamine (extractant) and 1-tridecanol (phase modifier) in n-dodecane in contact with an acidic aqueous sulfate solution containing chromium(VI) has been investigated. The kinetics of degradation and the degradation products have been determined. GC-MS analyses evidenced the formation of 1-tridecanal, di-n-octylamine, N,N,N-octen-1-yl-dioctylamine, and an unidentified degradation compound, which may have contained a double bond and a carboxylic acid function. The mechanisms of degradation have been discussed on the basis of these identified degradation compounds. The study of the degradation kinetics showed that an increase of tri-n-octylamine concentration in the organic phase is responsible for a decrease of the degradation rate, while an increase in sulfuric acid concentration in the aqueous phase leads to a strong increase in the degradation rate. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
Hydrometallurgical Approach for Leaching of Metals from Copper Rich Side Stream Originating from Base Metal Production
Metals 2018, 8(1), 40; https://doi.org/10.3390/met8010040 - 08 Jan 2018
Cited by 5
Abstract
Pyrometallurgical metal production results in side streams, such as dusts and slags, which are carriers of metals, though commonly containing lower metal concentrations compared to the main process stream. In order to improve the circular economy of metals, selective leaching of copper from [...] Read more.
Pyrometallurgical metal production results in side streams, such as dusts and slags, which are carriers of metals, though commonly containing lower metal concentrations compared to the main process stream. In order to improve the circular economy of metals, selective leaching of copper from an intermediate raw material originating from primary base metal production plant was investigated. The raw material investigated was rich in Cu (12.5%), Ni (2.6%), Zn (1.6%), and Fe (23.6%) with the particle size D80 of 124 µm. The main compounds present were nickel ferrite (NiFe2O4), fayalite (Fe2SiO4), cuprite (Cu2O), and metallic copper. Leaching was studied in 16 different solutions. The results revealed that copper phases could be dissolved with high yield (>90%) and selectivity towards nickel (Cu/Ni > 7) already at room temperature with the following solutions: 0.5 M HCl, 1.5 M HCl, 4 M NaOH, and 2 M HNO3. A concentration of 4 M NaOH provided a superior selectivity between Cu/Ni (340) and Cu/Zn (51). In addition, 1–2 M HNO3 and 0.5 M HCl solutions were shown to result in high Pb dissolution (>98%). Consequently, 0.5 M HCl leaching is suggested to provide a low temperature, low chemical consumption method for selective copper removal from the investigated side stream, resulting in PLS (pregnant leach solution) which is a rich in Cu and lead free residue, also rich in Ni and Fe. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessArticle
A Mineralogical Assessment on Residues after Acidic Leaching of Bauxite Residue (Red Mud) for Titanium Recovery
Metals 2017, 7(11), 458; https://doi.org/10.3390/met7110458 - 28 Oct 2017
Cited by 8
Abstract
Due to its alkalinity, red mud produced by the Bayer process may affect both the environment and human health. For this reason, its further utilization instead of disposal is of great importance. Numerous methods have already been studied for hydrometallurgical treatment of red [...] Read more.
Due to its alkalinity, red mud produced by the Bayer process may affect both the environment and human health. For this reason, its further utilization instead of disposal is of great importance. Numerous methods have already been studied for hydrometallurgical treatment of red mud, especially for the recovery of various metallic components such as iron, aluminum, titanium or rare earth elements. This study focuses on the extraction of titanium from red mud and in particular the mineralogical changes, induced by leaching. Sulfuric acid, hydrochloric acid and their combination have been utilized as leaching agents with the same leaching parameters. It has been determined that sulfuric acid is the best candidate for the red mud treatment in terms of titanium leaching efficiency at the end of 2 h with a value of 67.3%. Moreover, samples from intermediate times of reaction revealed that leaching of Ti exhibit various reaction rates at different times of reaction depending on acid type. In order to explain differences, X-ray Diffraction (XRD), scanning electron microscope (SEM) and QEMSCAN techniques were utilized. Beside titanium oxide (TiO2) with available free surface area, a certain amount of the TiO2 was detected as entrapped in Fe dominating oxide. These associations between Ti and Fe phases were used to explain different leaching reaction rates and a reaction mechanism was proposed to open a process window. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Graphical abstract

Review

Jump to: Editorial, Research

Open AccessReview
Refining Approaches in the Platinum Group Metal Processing Value Chain—A Review
Metals 2018, 8(4), 203; https://doi.org/10.3390/met8040203 - 22 Mar 2018
Cited by 1
Abstract
Mineable platinum group metal (PGM) deposits are rare and found in relatively few areas of the world. At the same time, the use of PGM is predicted to expand in green technology and energy applications, and PGMs are consequently currently listed as European [...] Read more.
Mineable platinum group metal (PGM) deposits are rare and found in relatively few areas of the world. At the same time, the use of PGM is predicted to expand in green technology and energy applications, and PGMs are consequently currently listed as European Union critical metals. Increased mineralogical complexity, lower grade ores, and recent PGM production expansions give rise to the evaluation of the value chain of the capital-intensive conventional matte smelting treatment and other processing possibilities of the ore. This article will review the processes and value chain developed to treat ores for PGM recovery, highlighting hydrometallurgical refining approaches. It groups processes according to their rationale and discusses the special features of each group. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Open AccessReview
Recovery of Gold from Pregnant Thiosulfate Solutions by the Resin Adsorption Technique
Metals 2017, 7(12), 555; https://doi.org/10.3390/met7120555 - 12 Dec 2017
Cited by 8
Abstract
This review is devoted to an integrated evaluation of the current use and future development of the resin adsorption technique in gold recovery from pregnant thiosulfate solutions. Comparisons are firstly made with other recovery techniques, including precipitation, activated carbon adsorption, solvent extraction, electrowinning [...] Read more.
This review is devoted to an integrated evaluation of the current use and future development of the resin adsorption technique in gold recovery from pregnant thiosulfate solutions. Comparisons are firstly made with other recovery techniques, including precipitation, activated carbon adsorption, solvent extraction, electrowinning and mesoporous silica adsorption. A detailed discussion about the recent advances of the technique in gold recovery from pregnant thiosulfate solutions is then presented from the aspects of gold adsorption on the resins and gold-loaded resin elution, respectively. On the basis of summarizing the present research, the major limitations of the resin adsorption technique are eventually pointed out and future development will also be prospected. Full article
(This article belongs to the Special Issue Advances in Hydrometallurgy)
Show Figures

Figure 1

Back to TopTop