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Metals
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Leaching/Bioleaching and Recovery of Metals
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Leaching/Bioleaching and Recovery of Metals

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

Deadline for manuscript submissions: closed (30 June 2021) | Viewed by 28873

Special Issue Editors

Prof. Dr. Maria Luisa Blázquez Izquierdo

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Guest Editor
Department of Chemical and Materials Engineering, Complutense University of Madrid, Madrid, Spain
Interests: hydrometallurgy; bio-hydrometalurgy; biosorption; biosynthesis of nanoparticles
Prof. Dr. Jesús A. Muñoz Sánchez

E-Mail Website
Guest Editor
Department of Chemical and Materials Engineering, Complutense University of Madrid, Madrid, Spain
Interests: hydrometallurgy; bio-hydrometalurgy, biosorption; biosynthesis of nanoparticles
Dr. Laura Castro

E-Mail Website
Guest Editor
Department of Chemical and Materials Engineering, Complutense University of Madrid, 28040 Madrid, Spain
Interests: biohydrometallurgy; bioleaching; biosynthesis of nanoparticles; bioadsorption
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Hydrometallurgical processes for metal extraction are becoming more and more popular as average ore grades are declining and huge tonnages of tailings and recycle materials containing valuable metals are being accumulated all around the world. Hydrometallurgy and more recently bio-hydrometallurgy have brought some added value to these processes, since they can recover large amounts of metals using aqueous solutions and chemical reagents that could be provided by certain microorganisms. In addition, environmental risks associated to the accumulation of hazardous residues from metallurgical industries could be overcome by applying bio/hydrometallurgical methods. Hydrometallurgy of base metals, particularly Cu, Zn, Ni, etc., is a well-documented process, but other metals, particularly strategic ones (cobalt, lithium, rare earths, etc.) have not yet deserved so much attention by the scientific community. In the same way, the field of bio-hydrometallurgy has been focused mainly on a few metals, so there is still room for improvement.

The Special Issue will be devoted to collecting papers on recent advances on chemical and biological dissolution of metals from diverse raw materials and to the recovery of metals from aqueous solutions using different bio/chemical processes. These include studies reporting the novelty results of such aspects, particularly those relative to strategic metals, from both a fundamental scientific and an industrial point of view.

Prof. Dr. Maria Luisa Blázquez Izquierdo
Prof. Dr. Jesús A. Muñoz Sánchez
Dr. Laura Castro
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

  • Hydrometallurgy
  • Bio-hydrometallurgy
  • Metal
  • Mineral
  • Leaching
  • Bioleaching
  • Recovery
  • Recycling

Published Papers (10 papers)

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Editorial

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3 pages, 203 KiB  
Editorial
Leaching/Bioleaching and Recovery of Metals
by Laura Castro, María Luisa Blázquez and Jesús Ángel Muñoz
Metals 2021, 11(11), 1732; https://doi.org/10.3390/met11111732 - 29 Oct 2021
Cited by 1 | Viewed by 1349
Abstract
Hydrometallurgical processes for metal extraction are becoming more and more popular as average ore grades are declining and huge tonnages of tailings and recycle materials containing valuable metals are being accumulated all around the world [...] Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)

Research

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15 pages, 3999 KiB  
Article
Arsenate and Arsenite Sorption Using Biogenic Iron Compounds: Treatment of Real Polluted Waters in Batch and Continuous Systems
by Laura Castro, Lesly Antonieta Ayala, Arevik Vardanyan, Ruiyong Zhang and Jesús Ángel Muñoz
Metals 2021, 11(10), 1608; https://doi.org/10.3390/met11101608 - 10 Oct 2021
Cited by 7 | Viewed by 2105
Abstract
Arsenic pollution in waters is due to natural and anthropogenic sources. Human exposure to arsenic is associated with acute health problems in areas with high concentrations of this element. Nanometric iron compounds with large specific surface areas and higher binding energy produced by [...] Read more.
Arsenic pollution in waters is due to natural and anthropogenic sources. Human exposure to arsenic is associated with acute health problems in areas with high concentrations of this element. Nanometric iron compounds with large specific surface areas and higher binding energy produced by some anaerobic microorganisms are thus expected to be more efficient adsorbents for the removal of harmful metals and metalloids than chemically produced iron oxides. In this study, a natural consortium from an abandoned mine site containing mainly Clostridium species was used to biosynthesize solid Fe(II) compounds, siderite (FeCO3) and iron oxides. Biogenic precipitates were used as adsorbents in contact with solutions containing arsenate and arsenite. The adsorption of As(V) fitted to the Langmuir model (qmax = 0.64 mmol/g, KL = 0.019 mmol/L) at the optimal pH value (pH 2), while the As(III) adsorption mechanism was better represented by the Freundlich model (KF = 0.476 L/g, n = 2.13) at pH 10. Water samples from the Caracarani River (Chile) with high contents of arsenic and zinc were treated with a biogenic precipitate encapsulated in alginate beads in continuous systems. The optimal operation conditions were low feed flow rate and the up-flow system, which significantly improved the contaminant uptake. This study demonstrates the feasibility of the application of biogenic iron compounds in the treatment of polluted waters. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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14 pages, 4670 KiB  
Article
Pretreatment to Leaching for a Primary Copper Sulphide Ore in Chloride Media
by Víctor Quezada, Antoni Roca, Oscar Benavente, Montserrat Cruells, Evelyn Melo and María Hernández
Metals 2021, 11(8), 1260; https://doi.org/10.3390/met11081260 - 10 Aug 2021
Cited by 4 | Viewed by 2036
Abstract
The dissolution of copper sulphide ores continues to be a challenge for the copper industry. Several media and leaching alternatives have been proposed to improve the dissolution of these minerals, especially for the leaching of chalcopyrite. Among the alternatives, pretreatment prior to leaching [...] Read more.
The dissolution of copper sulphide ores continues to be a challenge for the copper industry. Several media and leaching alternatives have been proposed to improve the dissolution of these minerals, especially for the leaching of chalcopyrite. Among the alternatives, pretreatment prior to leaching was proposed as an option that increases the dissolution of copper from sulphide ores. In this study, a mineral sample from a copper mining company was used. The copper grade of the sample was 0.79%, and its main contributor was chalcopyrite (84%). The effect of curing time (as pretreatment) in a chloride media on copper sulphide ore was evaluated at various temperatures: 25, 50, 70 and 90 °C. The pretreated sample and leaching residues were characterized by X-ray diffraction, scanning electron microscopy, and reflected light microscopy. Pretreatment products such as CuSO4, NaFe3(SO4)2(OH)6, and S0 were identified although with difficulty, due to the low presence of chalcopyrite in the initial sample (1.99%). Under the conditions of 15 kg/t of H2SO4, 25 kg/t of NaCl, and 15 days of curing time, a copper extraction of 93.1% was obtained at 90 °C with 50 g/L of Cl− and 0.2 M of H2SO4. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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17 pages, 5216 KiB  
Article
Deposition of Arsenic from Nitric Acid Leaching Solutions of Gold–Arsenic Sulphide Concentrates
by Kirill Karimov, Denis Rogozhnikov, Evgeniy Kuzas, Oleg Dizer, Dmitry Golovkin and Maksim Tretiak
Metals 2021, 11(6), 889; https://doi.org/10.3390/met11060889 - 28 May 2021
Cited by 12 | Viewed by 2906
Abstract
At present, the processing of refractory gold–arsenic sulphide concentrates is becoming more relevant due to the depletion of rich crude ore reserves. In the process of the nitric acid leaching of arsenic sulphide minerals, solutions are formed containing 20–30 g/L of arsenic (III). [...] Read more.
At present, the processing of refractory gold–arsenic sulphide concentrates is becoming more relevant due to the depletion of rich crude ore reserves. In the process of the nitric acid leaching of arsenic sulphide minerals, solutions are formed containing 20–30 g/L of arsenic (III). Since market demand for arsenic compounds is limited, such solutions are traditionally converted into poorly soluble compounds. This paper describes the investigation of precipitating arsenic sulphide from nitric acid leaching solutions of refractory sulphide raw materials of nonferrous metals containing iron (III) ions using sodium hydrosulphide with a molar ratio of NaHS/As = 2.4–2.6, which is typical for pure model solutions without oxidants. The work studied the effect of temperature, the pH of the solution and the consumption of NaHS and seed crystal on this process. The highest degree of precipitation of arsenic (III) sulphide (95–99%) from nitric acid leaching solutions containing iron (III) ions without seed occurs with a pH from 1.8 to 2.0 and a NaHS/As molar ratio of 2.8. The introduction of seed crystal significantly improves the precipitation of arsenic (III) sulphide. An increase in seed crystal consumption from 0 to 34 g/L in solution promotes an increase in the degree of transition of arsenic to sediment from 36.2 to 98.1% at pH = 1. According to SEM/EDS and XRF sediment data, from the results of experiments on the effect of As2S3 seed crystal consumption, acidity and molar ratio of NaHS/As on the precipitation of arsenic (III) sulphide and the Fetotal/Fe2+ ratio in the final solution, it can be concluded that the addition of a seed accelerates the crystallisation of arsenic (III) sulphide by increasing the number of crystallisation centres; as a result, the deposition rate of As2S3 becomes higher. Since the oxidation rate of sulphide ions to elemental sulphur by iron (III) ions does not change significantly, the molar ratio of NaHS/As can be reduced to 2.25 to obtain a precipitate having a lower amount of elemental sulphur and a high arsenic content similar to that precipitated from pure model solutions. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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13 pages, 2288 KiB  
Article
The Effect of Metal Ions on the Growth and Ferrous IronOxidation by Leptospirillum ferriphilum CC Isolated from Armenia Mine Sites
by Anna Khachatryan, Narine Vardanyan, Arevik Vardanyan, Ruiyong Zhang and Laura Castro
Metals 2021, 11(3), 425; https://doi.org/10.3390/met11030425 - 5 Mar 2021
Cited by 6 | Viewed by 2354
Abstract
The aim of this study is to investigate the potential of newly isolated strain Leptospirillum (L.) ferriphilum CC for bioleaching of pyrite and chalcopyrite in pure or mixed culture with other iron- and/or sulfur-oxidizing bacteria. In this paper, kinetics of ferrous [...] Read more.
The aim of this study is to investigate the potential of newly isolated strain Leptospirillum (L.) ferriphilum CC for bioleaching of pyrite and chalcopyrite in pure or mixed culture with other iron- and/or sulfur-oxidizing bacteria. In this paper, kinetics of ferrous iron (Fe2+) oxidation by newly isolated strain Leptospirillum (L.) ferriphilum CC was studied. The effect of initial Fe2+ in the concentration range of 50–400 mM on bacterial growth and iron oxidation was studied. It was shown that microbial Fe2+ oxidation was competitively inhibited by Fe3+. The influence of copper, zinc, nickel and cobalt ions on the oxidation of Fe2+ by L. ferriphilum CC was also studied. Minimal inhibitory concentrations (MIC) for each metal ion were determined. The toxicity of the ions was found to be as follows: Co > Zn > Ni > Cu. The comparison of iron oxidation kinetic parameters of L. ferriphilum CC with other strains of L. ferriphilum indicates the high potential of strain L. ferriphilum CC for biogenic regeneration of concentrated ferric iron (Fe3+) in bioleaching processes of ores and ore concentrates. Bioleaching tests indicated that the newly isolated L. ferriphilum CC can be a prospective strain for the bioleaching of sulfide minerals in pure culture or in association with other iron- and/or sulfur-oxidizing bacteria. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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18 pages, 4834 KiB  
Article
Microbial Processing of Waste Shredded PCBs for Copper Extraction Cum Separation—Comparing the Efficacy of Bacterial and Fungal Leaching Kinetics and Yields
by Abhilash, Shirin Tabassum, Anirban Ghosh, Pratima Meshram and Eric D. van Hullebusch
Metals 2021, 11(2), 317; https://doi.org/10.3390/met11020317 - 12 Feb 2021
Cited by 10 | Viewed by 2639
Abstract
The recycling of electronic scrap is an important subject not only from an environmental aspect but also for recovering metal resources such as copper. In this work, the microbial extraction of copper and other metals (Cu, Ni, Co, Fe and Al) present in [...] Read more.
The recycling of electronic scrap is an important subject not only from an environmental aspect but also for recovering metal resources such as copper. In this work, the microbial extraction of copper and other metals (Cu, Ni, Co, Fe and Al) present in the depopulated and shredded printed circuit board (PCB) is elaborated. Bacterial strains of A. ferrooxidans, A. thiooxidans and a fungal strain, A. niger are used for copper extraction along with other metals from shredded PCBs. An optimum metal recovery of 93% Cu was obtained at 308 K, pH 2 using 8% pulp density in 10 days by a mixed culture of A. ferrooxidans and A. thiooxidans. Whereas using A. niger, a metal recovery of 66% Cu was reported using similar experimental conditions. The results show the higher potential ability of bacteria as compared to fungus to bioleach copper. Additionally, the kinetics and mechanism of copper bioleaching from this e-waste by the chemolithotrophs and heterotrophs were evaluated. The leach liquor obtained from the optimized leaching process was subjected to separation and purification of copper as >99% pure copper sulfate using Acorga M5640 by solvent extraction. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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27 pages, 7517 KiB  
Article
Efficient Recovery of Rare Earth Elements (Pr(III) and Tm(III)) From Mining Residues Using a New Phosphorylated Hydrogel (Algal Biomass/PEI)
by Chunlin He, Khalid A.M. Salih, Yuezhou Wei, Hamed Mira, Adel A.-H. Abdel-Rahman, Khalid Z. Elwakeel, Mohammed F. Hamza and Eric Guibal
Metals 2021, 11(2), 294; https://doi.org/10.3390/met11020294 - 8 Feb 2021
Cited by 27 | Viewed by 3045
Abstract
With the target of recovering rare earth elements (REEs) from acidic leachates, a new functionalized hydrogel was designed, based on the phosphorylation of algal/polyethyleneimine beads. The functionalization strongly increased the sorption efficiency of the raw material for Pr(III) and Tm(III). Diverse techniques were [...] Read more.
With the target of recovering rare earth elements (REEs) from acidic leachates, a new functionalized hydrogel was designed, based on the phosphorylation of algal/polyethyleneimine beads. The functionalization strongly increased the sorption efficiency of the raw material for Pr(III) and Tm(III). Diverse techniques were used for characterizing this new material and correlating the sorption performances and mechanisms to the physicochemical structure of the sorbent. First, the work characterized the sorption properties from synthetic solutions with the usual procedures (study of pH effect, uptake kinetics, sorption isotherms, metal desorption and sorbent recycling, and selectivity from multi-element solutions). Optimum pH was found close to 5; sorption isotherms were fitted by the Langmuir equation (maximum sorption capacities close to 2.14 mmol Pr g−1 and 1.57 mmol Tm g−1). Fast uptake kinetics were modeled by the pseudo-second order rate equation. The sorbent was highly selective for REEs against alkali-earth and base metals. The sorbent was remarkably stable for sorption and desorption operation (using 0.2 M HCl/0.5 M CaCl2 solutions). The sorbent was successfully applied to the leachates of Egyptian ore (pug leaching) after a series of pre-treatments (precipitation steps), sorption, and elution. The selective precipitation of REEs using oxalic acid allows for the recovery of a pure REE precipitate. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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13 pages, 3907 KiB  
Article
Bioleaching of Phosphate Minerals Using Aspergillus niger: Recovery of Copper and Rare Earth Elements
by Laura Castro, Maria Luisa Blázquez, Felisa González and Jesús Angel Muñoz
Metals 2020, 10(7), 978; https://doi.org/10.3390/met10070978 - 20 Jul 2020
Cited by 36 | Viewed by 4800
Abstract
Rare earth elements (REE) are essential in high-technology and environmental applications, where their importance and demand have grown enormously over the past decades. Many lanthanide and actinide minerals in nature are phosphates. Minerals like monazite occur in small concentrations in common rocks that [...] Read more.
Rare earth elements (REE) are essential in high-technology and environmental applications, where their importance and demand have grown enormously over the past decades. Many lanthanide and actinide minerals in nature are phosphates. Minerals like monazite occur in small concentrations in common rocks that resist weathering. Turquoise is a hydrous phosphate of copper and aluminum scarcely studied as copper ore. Phosphate-solubilizing microorganisms are able to transform insoluble phosphate into a more soluble form which directly and/or indirectly contributes to their metabolism. In this study, bioleaching of heavy metals from phosphate minerals by using the fungus Aspergillus niger was investigated. Bioleaching experiments were examined in batch cultures with different mineral phosphates: aluminum phosphate (commercial), turquoise, and monazite (natural minerals). The experiments were performed at 1% pulp density and the phosphorous leaching yield was aluminum phosphate > turquoise > monazite. Bioleaching experiments with turquoise showed that A. niger was able to reach 8.81 mg/l of copper in the aqueous phase. Furthermore, the fungus dissolved the aluminum cerium phosphate hydroxide in monazite, reaching up to 1.37 mg/L of REE when the fungus was grown with the mineral as the sole phosphorous source. Furthermore, A. niger is involved in the formation of secondary minerals, such as copper and REE oxalates. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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14 pages, 2486 KiB  
Article
Biosorption of Rare Earth Elements by Different Microorganisms in Acidic Solutions
by Anja Breuker, Simon F. Ritter and Axel Schippers
Metals 2020, 10(7), 954; https://doi.org/10.3390/met10070954 - 15 Jul 2020
Cited by 18 | Viewed by 3064
Abstract
Acidic solutions from metal bioleaching processes usually contain mixtures of metals in different concentrations which need to be separated and concentrated in downstream processing. Aim of this study was to explore and compare biosorption of rare earth elements (REE) by different microorganisms in [...] Read more.
Acidic solutions from metal bioleaching processes usually contain mixtures of metals in different concentrations which need to be separated and concentrated in downstream processing. Aim of this study was to explore and compare biosorption of rare earth elements (REE) by different microorganisms in acidic solutions. Biosorption of REE by bacteria and fungi showed element selective biosorption. The gram-positive bacterium Bacillus subtilis showed a higher selectivity to ytterbium (Yb) and lutetium (Lu) than the gram-negative bacteria Leisingera methylohalidivorans and Phaeobacter inhibens. In contrast, the tested fungi (Catenulostroma chromoblastomyces, Pichia sp.) showed a preference for the middle rare earth elements. Algae exhibited a low biosorption performance. Additionally, for B. subtilis and one yeast (Pichia sp.), better results were achieved with living than dead biomass. This study compares for the first time biosorption of different microorganisms at standardized conditions at low pH und application related conditions. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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16 pages, 7278 KiB  
Article
Ammoniacal System Mechanisms for Leaching Copper from Converter Slag
by Alvaro Aracena, Andrés Valencia and Oscar Jerez
Metals 2020, 10(6), 712; https://doi.org/10.3390/met10060712 - 28 May 2020
Cited by 8 | Viewed by 2934
Abstract
In pyrometallurgical processes refining copper, the main source of loss in the conversion stage is from slag. This paper reports on research work treating converter slag containing high percentages of copper (36 wt%) using ammonium hydroxide at room temperature. Variables analyzed are solution [...] Read more.
In pyrometallurgical processes refining copper, the main source of loss in the conversion stage is from slag. This paper reports on research work treating converter slag containing high percentages of copper (36 wt%) using ammonium hydroxide at room temperature. Variables analyzed are solution pH, agitation, temperature, NH4OH concentration and particle size. Results showed that the hydronium ion resulting from ammonium hydroxide dissociation was the main oxidant of copper compounds in slag, such as CuO, Cu2O and Cu, with the exception of CuFeO2. The particles contain a large amount of microcracks (porosity) in their refractory structure (analyzed by compositional image capture (BSE)). Thus, the diffusion of the leaching solution through the microcracks making contact with the copper oxides would be allowed. Leaching mechanisms were corroborated by X-ray diffraction and scanning electron microscopy analysis. Increasing temperature and NH4OH concentration while decreasing particle size obtained higher copper recoveries, reaching values of 84.8%. Under the same conditions, the main impurity (iron) was minimal (<2%). Solution pH also affected slag leaching. Agitation of the solution positively affected the rate of copper extraction. Leaching kinetics of the leaching solution through the porosity formed in the slag was analyzed under the intraparticle diffusion model. The reaction order was 1.2 with respect to the concentration of ammonium hydroxide and the model was inversely proportional to the square of the particle radius. The activation energy obtained was 42.3 kJ/mol for temperature range 283 to 333 K. Full article
(This article belongs to the Special Issue Leaching/Bioleaching and Recovery of Metals)
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