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Abstract

The demand for metals is ever increasing with the advancement of the industrialized world. On the other hand, worldwide reserves of high grade ores are close to depletion. However, there exists a large reserve of metals in low and lean grade ores and other secondary sources. Metal recovery from low and lean grade ores using conventional techniques such as pyrometallurgy, etc. requires high energy and capital inputs which often result in the secondary environmental pollution. Thus, there is a need to utilize more efficient technologies to recover metals. Biohydrometallurgy, which exploits microbiological processes to recover metal ions, is regarded as one of the most promising and revolutionary biotechnologies. The products of such processes are dissolved in aqueous solution, thereby rendering them more amenable to containment, treatment and recovery. On top of this, biohydrometallurgy can be conducted under mild conditions, usually without the use of any toxic chemicals. Consequently, the application of biohydrometallurgy in the recovery of metals from lean grade ores and wastes has made it an eco-friendly technology for enhanced metal production. This paper reviews the current status of biohydrometallurgy of low grade ores around the world. Particular attention is focused on the bioleaching of black shale ore and its metallogenic diversity in the world. The review assesses the status of bioprocesssing of metals to evaluate promising developments. Bioleaching of metals is comprehensively reviewed with the emphasis on the contribution of microbial community, especially fungal bioleaching coupled with ultrasound treatment. In this manuscript, the principles of bioleaching, their mechanisms, and commercial applications are presented. The case studies and future technology directions are also reviewed

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... Facing the increasing market demand for vanadium products and environmental problems [1][2][3][4], the efficient and sustainable utilization of vanadium-bearing mineral resources is increasingly necessary and urgent for vanadium industry. Vanadium-bearing black shale has been identified to have enrichments of vanadium, which is distributed in many provinces of China [5,6]. There are vanadium enrichments in black shale elsewhere in the world include United states, Australia, Argentina, and Kazakhstan [7]. ...
... KAl2(AlSi3O10)(OH)2 + 10H + = 3Al 3+ + K + + 3H4SiO4 (6) According to the line slope in Figure 6, the apparent reaction order (n) of sulfuric acid decreased from 2.7 to 1.9 under K2SO4 assistance, which means that the pH dependence of Equation (6) has been weakened as K2SO4 mediated in pressure acid leaching of the black shale. K2SO4 indirectly prompted Equation (6), which should be attributed to the conversions between CaSO4 and CaSO4·2H2O. Figure 6. ...
... KAl2(AlSi3O10)(OH)2 + 10H + = 3Al 3+ + K + + 3H4SiO4 (6) According to the line slope in Figure 6, the apparent reaction order (n) of sulfuric acid decreased from 2.7 to 1.9 under K2SO4 assistance, which means that the pH dependence of Equation (6) has been weakened as K2SO4 mediated in pressure acid leaching of the black shale. K2SO4 indirectly prompted Equation (6), which should be attributed to the conversions between CaSO4 and CaSO4·2H2O. Figure 6. Plot of lnk as a function of sulfuric acid concentration. ...
Article
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During pressure acid leaching process of black shale-hosted vanadium, increasing the reaction interface of muscovite dissolution can enhance the vanadium release. In this paper, calcium sulfate (CaSO4) deposition behavior and its effect on muscovite under K2SO4 assistance were focused on for demonstrating the function of CaSO4 on vanadium leaching from the black shale. Results showed that as K2SO4 mediated, the apparent activation energy of vanadium leaching and the apparent reaction order of sulfuric acid decreased from 24.37 kJ/mol to 16.63 kJ/mol and 2.7 to 1.9, respectively. The leaching rate and dependence on pH value were modified. The vanadium leaching acceleration owed to CaSO4 deposition on muscovite in the black shale. The ion absorption stimulations found that Ca2+ is confirmed to be easily absorbed on the six-membered ring cavity of silicon-oxygen tetrahedrons in muscovite structure prior to K+ and Na+. Meanwhile, SO42− provides two oxygen atoms to bond with Ca2+ absorbed on muscovite (001) surface. The continuous absorption and bonding create CaSO4 deposition on muscovite (001) surface which also involves the load transmitting. The stress load transmitting correlates to pore formation in muscovite particles. It was proved that massive micropores initiated and proliferated in the existing pores under K2SO4 assistance. The porosity caused by CaSO4 deposition greatly increased the reaction interface of muscovite dissolution and accelerate internal diffusion of H+ to the reaction interface, which can significantly weaken the vanadium leaching dependence on acid.
... Autotrophs use light (photoautotrophs) or chemical energy from metals or sulfur-electron donors-(chemolithoautotrophic) to turn CO 2 into organic carbon molecules for the production of biomass. Heterotrophs, on the other hand, oxidize organic carbon, in which it generates many by-products such as acetic acid and citric acid that solubilize metals from minerals (Anjum et al. 2012;Jain and Sharma 2004;Natarajan 2018). ...
... However, there are heterotrophic organisms usually present in non-sulfuric mines. Among the bacteria, the genera Bacillus and Pseudomonas are the most common, while among the fungi the most important are Aspergillus and Penicillium (Anjum et al. 2012;Bosecker 1997;Jain and Sharma 2004). ...
... In the indirect mechanism of contact, the microorganism adheres (partially) to the surface of the mineral and, therefore, the electrochemical interactions are attributed to the solubilization of metals. Nevertheless, in the indirect mechanism of noncontact, organic, or inorganic acids generated at the end of the procedure, with the culture medium already practically depleted (extremely low pH and high temperature), can help themselves as a leaching agent (Anjum et al. 2012). Moreover, in the indirect cooperative mechanism, there is the dissolution of sulfur colloids, sulfuric intermediates and various minerals fragmented by planktonic bacterial cells. ...
Chapter
Mineral coal is one of the most employed natural resources that represent potential environmental issues. The mine tailing contains several valuable minerals such as zinc, molybdenum, vanadium, chromium, iron, and copper. Currently, the most part of mine tailings is disposed at large tailing ponds. Another important tailing from mineral coal is fly ash, the main residue from thermoelectric plants, which may also contain valuable minerals. Currently, the most part of coal fly ash produced is used as raw material for cement fabrication or disposed at ash ponds. In this sense, biomining and bioleaching is an economically and environmentally attractive technology that can be used for metal recovery from residues such as mine tailing and coal ash, in line up with the concept of green chemistry. There are sparse data available on bioleaching of coal ash using either autotrophic or heterotrophic microorganisms. Therefore, the aim of this chapter was to describe the key aspects related to biomining and bioleaching of mine tailing and coal ash, pointing out the state of the art and some future perspectives.
... After that, metals are reclaimed by a number of chemical approaches including "solvent extraction, electrolytic deposition and precipitation" in the following procedures. Organic acid, inorganic acid, bacterial or alkaline solution are usually used as leaching media for cathode active material leaching [116][117][118][119][120][121][122][123][124][125][126][127][128][129][130][131] . In addition, some secondary 12 processes including mechanical chemistry and ultrasonic wave are often adopted in order to improve the leaching efficiency e.g. ...
... In addition, some secondary 12 processes including mechanical chemistry and ultrasonic wave are often adopted in order to improve the leaching efficiency e.g. Bacterial, Fungal /Bioleaching 116,[118][119][120][121][122][123][124][125][126][127][128][129][130] . ...
Article
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Owing to the increasing pressure on ecological effect of solid waste disposal and developing need for disposing of corresponding hazardous metals, recovery of spent lithium-ion batteries (LIBs) has gain worldwide attention in recent years. Lot of work has been done in this regard in past few decades and several new, interesting and unique methods have been developed to recycle cathode, anode and electrolyte. Therefore, it is need of hour to summarize the highlights in this emerging area to facilitate the young researchers. In this review starting from the current market demand and commercial value of lithium ion batteries we have summarized the most recent progress in the direction of recycling cathode, anode materials and electrolyte. At the beginning, an overview of recycling techniques is presented to grasp understanding of the topic. Later, laboratory and industrial investigations and implementation are reviewed with emphasis on anode (graphite) and electrolyte recovery. Life cycle assessment of end-of-life LIB recycling, limitations and future efforts have also mentioned to focus on improving the efficiency of metal extraction and separation with sustainable and systematic recycling of spent lithium ion batteries.
... Furthermore, the vanadium product extracted from stone coals is just 40% of the total vanadium product of China, which is much less than that extracted from vanadium titanomagnetite ores. Therefore, developing feasible methods of extracting vanadium from stone coal is of practical significance to satisfy the growing global demand of vanadium [6,7]. ...
... The relationship between Gibbs free energy and temperature of reaction (2)-(6).transformation during roasting process at a scanning speed of 10 • /min and a diffraction angle of 2θ ranging from 5 • to 90 • . ...
Article
In this work, a two-stage roasting technology was presented to promote the vanadium leaching efficiency. The effects of roasting factors of two-stage roasting method on vanadium leaching rate and the mechanism of extracting vanadium from stone coal were studied. Phase transformation of minerals during roasting was analyzed with X-ray diffraction (XRD). Microstructure change was studied using scanning electron microscope (SEM), energy dispersive spectrum (EDS) and Brunauer-Emmett-Teller (BET) analyses. The results showed that under the optimal conditions, i.e., first-stage roasting temperature of 650 °C, roasting time of 1 h, air atmosphere and second stage roasting temperature of 950 °C, roasting time of 3 h, 30% oxygen concentration atmosphere, a vanadium leaching recovery of 80.26% was obtained. The results of this study confirmed that the two-stage roasting technology could be a more environment-friendly and effective method for extracting vanadium from stone coal.
... The chemoorganotrophs, also known as heterotrophic microorganisms, obtain their required energy from the organic compounds (Anjum et al., 2012). Filamentous fungi, including Aspergillus sp. and Penicillium sp. ...
... This kind of solubilization occurs in higher pH values and is known as alkaline leaching (Anjum et al., 2010). Redoxolysis refers to oxidation and/or reduction of metals in an acidic environment, in which the mobilization rate depends on the type and oxidation state of the metal (Srichandan et al., 2019;Anjum et al., 2012). A combination of these mechanisms may also be implemented. ...
Article
The rapidly growing demand for lithium has resulted in a sharp increase in its price. This is due to the ubiquitous use of lithium-ion batteries (LIBs) in large-scale energy and transportation sectors as well as portable devices. Recycling of the LIBs for being the supply of critical metals hence becomes environmentally and economically viable. The presently used approaches for the recovery of spent LIBs like pyrometallurgical process can effectively recover nickel, cobalt, and copper, while lithium is usually lost in slag. Bioleaching process as an alternative method of extraction and recovery of valuable metals from the primary and secondary resources has been attracting a large pool of attraction. This method can provide with higher recovery yield even for low concentration of metals which makes it viable among conventional methods. The bioleaching process can work with lower operating cost and consumed water and energy along with a simple condition, which produces less hazardous by-products ultimately. Here, we comprehensively review the biology and chemistry mechanisms of the bioleaching process with a conclusive discussion to help how to extend the use of bioleaching for lithium extraction and recovery from the spent LIBs with a focus on recovery yields improvement. We elaborate on the three main types of the reported bioleaching with considering effective parameters including temperature, initial pH, pulp density, aeration, and medium and cell nutrients to sustain microorganism activity. Finally, practical challenges and future opportunities of lithium are discussed to inspire future research trends and pilot studies to realize the full potential of lithium recovery using sustainable bioleaching processes to extend a clean energy future.
... Chemolithoautotrophs used in biomining are acidophilic microorganisms, which are having the ability to fix CO2 by oxidizing the ferrous iron or reduced sulfur and produces ferric iron or H2SO4. 12 Solubilization of metal sulphides by ferric iron or H2SO4 decreases the pH of surrounding and as a result further enhance the solubilization of metals, 23 because low pH (1.5-3.0) is best for microbial leaching due to the fact that at low pH most of the metals stay in solution. 24 Leptospirillum ferrooxidans and Acidithiobacillus thiooxidans mediate in the process of bioleaching. ...
... 56 Indirect bioleaching method is most appropriate for lower sulfur and sulfide minerals as sources for H2SO4 production by autotrophs. 23 In addition to the laboratory leaching techniques (Percolator leaching, submerged leaching and column leaching), leaching techniques used in industrial scale leaching are dump leaching, heap leaching, tank leaching and underground leaching. Brief of the industrial leaching techniques is described in Table 1. ...
Article
Abstract Biomining of copper from ores was started during ancient era without even knowing the role of microorganisms in the process. The ever-increasing demand of metals, declination of natural resources, huge reserves of low-grade metallic ores and generation of massive amount of metallic wastes from mining and beneficiation process has led to the evolution and commercial scale adoption of biomining. The ability of microorganisms to bioamine metals depends on redox reactions, organic or inorganic acid formation an d the release of complexing agents. Redox reaction is the key step of biomining process which is based either on direct or indirect bioleaching. The main difference between the two mechanisms is the direct contact between the microorganisms and the reduced minerals. Apart from the economic benefits, biomining also reduces the problem of acid mine drainage (AMD). Biomining is successfully utilized in metal recovery from low grade ores, mine tailings, mine wastes, municipal solid waste dump sites, legacy wastes, incinerator ash, E-wastes and, shales and tars etc. In this way, biomining inhibits the release of heavy metals from various types of wastes to the environment and release of toxic gases from the municipal solid waste dump sites and legacy wastes. Keywords Archaebacteria; bioleaching; chemolithoautotrophic bacteria
... In the direct mechanism, the microbial cell must attach to the surface of the particles. The adsorption of cells to particles depends on the electrochemical interactions and takes place within some minutes or hours (Anjum et al., 2012). Whereas, in the indirect mechanism, the bacteria will generate soluble compounds, which react with metals in the particle surface, and then gradually diffuse into the inside of particles (Li et al., 2015). ...
... During the first stage, the microorganisms are allowed under appropriate cultural conditions to grow in an adequate medium in order to produce active metabolites for the leaching process. After that, in the second stage the spent culture medium, under aggressive leaching conditions (low pH, high temperature, etc.), is used as a leaching agent of gold in the growing microorganisms' absence (Anjum et al., 2012). Extensive studies on bioleaching of gold from E-waste demonstrated that the biogenic cyanide was the sole mobilisation agent in the following reaction (Isildar et al., 2016;Liu et al., 2016): ...
Article
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Nowadays, large amount of municipal solid waste is because of electrical scraps (i.e. waste electrical and electronic equipment) that contain large quantities of electrical conductive metals like copper and gold. Recovery of these metals decreases the environmental effects of waste electrical and electronic equipment (also called E-waste) disposal, and as a result, the extracted metals can be used for future industrial purposes. Several studies reported in this review, demonstrated that the biohydrometallurgical processes were successful in efficient extraction of metals from electrical and electronic wastes. The main advantages of biohydrometallurgy are lower operation cost, less energy input, skilled labour, and also less environmental effect in comparison with pyro-metallurgical and hydrometallurgical processes. This study concentrated on fundamentals and technical aspects of biohydrometallurgy. Some points of drawbacks and research directions to develop the process in the future are highlighted in brief.
... Over the last two decades, a number of laboratory-scale studies have been reported for the bioleaching of different elements including REEs (Anjum et al., 2012;Edraki et al., 2014;Johnson, 2013). Various bioleaching methods were used including; heap (Jia et al., 2016;Ollakka et al., 2016), column (Jalali et al., 2019), dump (Groudeva et al., 2010), shake flasks (Shah et al., 2020a), in-situ (Richter et al., 2018) and stir tank reactors bioleaching (Zhou et al., 2009). ...
... Various bioleaching methods were used including; heap (Jia et al., 2016;Ollakka et al., 2016), column (Jalali et al., 2019), dump (Groudeva et al., 2010), shake flasks (Shah et al., 2020a), in-situ (Richter et al., 2018) and stir tank reactors bioleaching (Zhou et al., 2009). Laboratory-scale experiments can help in determining the bioleaching parameters at optimum conditions (Anjum et al., 2012) and is of prime importance for understanding the factors that may limit the industrialization of such process at pilot and full scales. Most of the bench scale bioleaching experiments are conducted at controlled conditions and low pulp densities. ...
Article
The growing demand for rare earth elements (REEs) confronted with a parallel supply risk, draws major interest to utilize secondary resources bearing higher REE content than the primary resources. The European Commission has recently identified bauxite as a Critical Raw Material (CRM). In particular, unexploited bauxite residues have invited due attention owing to their abundance (worldwide generation at 120 – 150 million tons/yr) and presence of REEs (0.5 - 1.7 kg/ton) and scandium (Sc) in particular, with Fe: 14–45%, Al: 5–14%, Si: 1–9%, Na: 1–6% and Ti: 2–12%. Nevertheless, it has also to be taken into consideration that higher amassing of this waste is turning into a global concern due to its hazardous impacts and disposal issues owing to its high alkalinity, fine particle size and metal content. Industrial valorization of REEs from stockpiled bauxite residues could possibly unlock approximately a 4.3 trillion-dollar economy globally. This review foresees bauxite as a potential resource for REEs and identifies the problems associated with disposal of bauxite residues. Considering the recycling potential of bauxite residues for supplying valuable metals for technology, biotechnology is seen as a promising alternative to the conventional methods. Comprehensive details including role and challenges of biotechnology in green recovery of REEs from bauxite residues, their scale-up and environmental issues are critically discussed. Furthermore, w.r.t. the bauxite residues, the REE market potential is presented with discussions into future prospects, following the current impact of COVID-19 pandemic on the demand and supply of REE to industrial sectors.
... Bioleaching can be achieved by contact and non-contact mechanisms. In contact mechanism, a non-random physical contact occurs between the mineral sulphide and bacterial cell 52 . Oxidation to sulphate occurs through several reactions catalysed by enzymes and causes electron transfer from the mineral surface 53 . ...
... Oxidation to sulphate occurs through several reactions catalysed by enzymes and causes electron transfer from the mineral surface 53 . In non-contact mechanism, there is no physical contact between the bacterial cell and mineral surface 52 . Bacteria generate lixiviant (ferric iron) which chemically oxidizes the sulphide mineral. ...
... They also have the advantages of low production costs, simple equipment, mild reaction conditions and reduced environmental impact. Hence, (bio)hydrometallurgical processing is especially suitable for the treatment of low-grade, complex and refractory mineral resources, industrial solid waste and secondary resources (Anjum et al., 2012;Kocaman et al., 2016). After more than half a century of development, (bio)hydrometallurgy has been explored to treat sulfide minerals of copper, nickel, cobalt, zinc, gold-bearing arsenopyrites and the desulfurization of coal. ...
Article
(Bio)Hydrometallurgy is a relatively economical and eco-friendly processing technology for sulfide minerals. Sulfide minerals degradation at abandoned mine sites also results in complex environmental problems. Although extensive studies have been done to explore the dissolution mechanisms of various sulfide minerals in acidic (microbial) sulfate environments, a systematic comparison of the findings is still needed. This paper summarizes the research into the dissolution mechanisms of several sulfide minerals, predominantly under bioleaching conditions. Especially, electrochemical cyclic voltammetry studies of various minerals are shown. Additionally, effects on the solid phase, including decomposition products and precipitates formed during the degradation processes, are discussed.
... At pH 7.8, activation of a different binding site was observed [46]. Presumably, the tested strain may also produce alkaline complexing agents as metabolites from the catabolism of proteins [47]. These metabolites may dissolve Mn by the formation of soluble metal complexion, which could easily bind to the bacteria cell surface. ...
Article
Full-text available
Manganese (Mn) is widely used in industry. However, its extensive applications have generated a great amount of manganese waste, which has become an ecological problem and has led to a decrease in natural resources. The use of microorganisms capable of accumulating Mn ions from contaminated ecosystems offers a potential alternative for the removal and recovery of this metal. The main aim of this work was an investigation of removal potential of Mn from soil by isolated bacterial. For this purpose, eleven bacterial strains were isolated from the soil from metallurgical waste heap in Upper Silesia, Poland. Strain named 2De with the highest Mn removal potential was selected and characterized taking into account its ability for Mn sorption and bioaccumulation from soil and medium containing manganese dioxide. Moreover, the protein profile of 2De strain before and after exposition to Mn was analyzed using SDS/PAGE technique. The 2De strain was identified as a Pseudomonas sp. The results revealed that this strain has an ability to grow at high Mn concentration and possesses an enhanced ability to remove it from the solution enriched with the soil or manganese dioxide via a biosorption mechanism. Moreover, changes in cellular protein expression of the isolated strain were observed. This study demonstrated that autochthonous 2De strain can be an effective tool to remove and recover Mn from contaminated soil.
... For the last half-century, hydrometallurgical processes have had an increasingly important role in the metal industries. Hydrometallurgy and, lately, biohydrometallurgy allow recovery of metals even from very poor deposits [14][15][16]. It is estimated that about 18% of the copper manufactured in the world is recovered by hydrometallurgical processes [17]. ...
Article
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This study investigates copper(II) ion transport through a polymer inclusion membrane (PIM) containing 1-alkyl-1,2,4-triazole (n = 8, 9, 10, 11, 12, 14), o-nitrophenyl octyl ether as the plasticizer and cellulose triacetate as the polymer matrix. The feeding phase was a solution of 0.1 mol/dm3CuCl2 and an equimolar (0.1 mol/dm3) mixture of copper, nickel, and cobalt chlorides with varying concentrations of chloride anions (from 0.5 to 5.0 mol/dm3) established with NaCl. The receiving phase was demineralized water. The flow rate of the source and receiving phases through the membrane module was within the range from 0.5 cm3/min to 4.5 cm3/min. The tests were carried out at temperatures of 20, 30, 40 and 50 °C. Transport of NaCl through the membrane was excluded for the duration of the test. It was noted that the flow rate through the membrane changes depending on the length of the carbon chain in the alkyl substituent from 16.1 μmol/(m2s) to 1.59 μmol/(m2s) in the following order: C8> C9> C10> C11> C12> C14. The activation energy was 71.3 ± 3.0 kJ/mol, indicating ion transport through the PIM controlled with a chemical reaction. Results for transport in case of the concurrent separation of copper(II), nickel(II), and cobalt(II) indicate a possibility to separate them in a selective manner.
... The use of microorganisms in leaching and beneficiation of lowgrade ores and minerals is widely considered an efficient, economical and environmentally benign alternative to conventional hydrometallurgical operations (Anjum et al., 2012;Işıldar et al., 2019;Srichandan et al., 2019;Sukla et al., 2019). Filamentous fungi can be successfully employed for the bioleaching of metals from low-grade ores as reported by Urik et al. which showed that aluminum bioleaching efficiency using A. niger was 2.7 times greater compared to leaching efficiency with hydrochloric acid at pH 2 (Urík et al., 2018). ...
Article
In this study, an economical and sustainable bio-hydrometallurgical route was evaluated for the recovery of aluminum from low-grade bauxite using the marine-derived fungus Aspergillus niger. Firstly, four different solid media were tested for high-yield spore production. Organic acid production capacity by A. niger was also evaluated in a medium supplemented with glucose or low-cost molasses as a carbon source using fungal spores or pellets as inoculum. The concentrations of the produced organic acids were determined by High-Performance Liquid Chromatography (HPLC). The results showed that oat-agar can be used as an inexpensive solid medium for greater fungal sporulation, while the liquid medium supplemented with molasses as a low-cost carbon source can be used for higher organic acids production. Among the conditions tested, A. niger spore inoculum showed the highest yield of the total produced organic acids (122.40 g L⁻¹ or 81.6% (grams of sucrose used per grams of total acid) and also the highest (1.02 ± 0.02 g L⁻¹ h⁻¹) acids production rate using molasses as an inexpensive carbon source. This cultivation condition was selected for the bioleaching studies with low-grade bauxite. Among the three different bioleaching methods tested, the direct two-steps bioleaching process resulted in higher aluminum leaching (91.2%) compared to indirect (84.8%) and direct one-step (82.8%) bioleaching process. According to the results obtained using marine-derived A. niger under the established culture conditions, proved to be an eco-friendly and cost-effective way for aluminum recovery from low-grade bauxite ore and has the potential to be adopted on a pilot scale.
... In oxidative bioleaching, both reactions as oxidation of elemental sulfur (S 0 ) and reduction of molecular oxygen (O 2 ) are coupled and produce sulfuric acid (H 2 SO 4 ) given in Fig. 1 (Anjum et al., 2012;Maluckov, 2017). Among the detected sulfur species on the surface of chalcopyrite, elemental sulfur (S 0 ), polysulfide (S n 2À ) or jarosite (represented by SO 4 2À ) have been reported as major components of a passivation layer (Zhu et al., 2011;Yang et al., 2013). ...
Article
The recovery of copper from secondary waste resources (e.g. electronic wastes, slag, fly-ash, sludge and spent catalysts) via oxidative and reductive bioleaching becomes a running trend and a potential alternative to limited metal supply. The motive of this review is to ponder over recycling of secondary waste towards the circular economy to reduce environmental risks as well as to increase the economic profitability of the mining industry. The biochemistry of iron/sulfur minerals, bacteria–mineral interactions and adaptive behavior allowing the acidophiles to survive are among the key parameters to be optimized during the bio recovery of copper. The use of OMICS approaches such as genomics, proteomics, transcriptomics and metabolomics is also crucial to elucidate a comprehensive view of the bioleaching communities, their mechanisms and interactions with minerals. This handy information can act as a boon to develop potential strains by adopting synthetic biology and antiviral CRISPR-Cas9 technologies to efficiently control the bioleaching process. Furthermore, some of these recent discoveries to design bioelectrochemical system (BES) and to achieve higher rate of metal recovery are discussed. Finally, the objective of this study is to narrow the gap between fundamental and applied research to fully address scientific, technological and economic challenges and bottlenecks of bioleaching process in general and BES in particular.
... Biological leaching was proved to be efficient for sulfides of Co, Ga, Mo, Ni, Zn and Pb [15]. Sulfide minerals including metals of the platinum group (Pt, Rh, Ru, Pd, Os and Ir) can be also subjected to preprocessing with microorganisms [61]. In recent decade, pilot tests on heap leaching of low-grade copper and nickel sulfide ores were launched (the mines involved are Radio Hill in the Western Australia; Talvivaara, Sotkamo in Finland; Khami, Sintszyan in PRC) [62][63][64][65][66][67][68][69][70]. ...
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The processing of previously unclaimed ores and wastes as sources of non-ferrous metals, with an associated reduction in the environmental burden, is a promising field of research. Besides, many relatively minor non-ferrous metal deposits with complex mining engineering and geological properties exist, whose development by conventional mining methods is not economically feasible. The theoretical possibility of processing the cut-off grade copper-nickel objects of Murmansk Region was shown. Process conditionswere found making the process economically feasible. Processing these mineral feed types will also allow in the long term to improve the environmental situation in the region.
... However, they also have several drawbacks, such as large capital expenditure for the construction of the leaching equipment, maintenance of the bed permeability under acidic leaching conditions, control of the acid consumption, inventory and cycle time management, and water management. Acid consumption in the pressure acid leaching process was less than in atmospheric leaching with iron precipitation as jarosite [5]. Low levels of sulphuric acid were used to extract of vanadium from black shale ores using the sulphation atmospheric leaching process, in conjunction with relatively low levels of recovery. ...
Article
This paper presents the results of physical and chemical investigation of black shale ore, as well as the investigation of combination of hydro- and pyrometallurgical methods in the sintering process of black shale ore with ammonium hydrosulfate to convert metals into water-soluble form. The homogeneous composite of black shale ore taken for the study consists of 67 % SiO2, 18 % C and 3 % H2O, 0.683 % V, 0.0415 Mo, 0.0148 % U3O8 and other components. Thermogravimetric analysis of sintering of carbon-silica ore with ammonium hydrosulfate in the presence of sulfuric acid was performed in the temperature range 20-1000 °C. It is established that at low-temperature sintering of ore with hydrosulfate ammonium after further leaching with sulfuric acid solution the extraction of uranium, vanadium, molybdenum and rare earth metals is 98.2 %, 91.3 %, 82.2% and 78.3 % respectively. The optimal leaching temperature is 90 °C, the ratio S: L = 1:3, and the leaching time is 2 hours.
... Mechanical processing was carried out on the collected PCBs by comminution and magnetic separation aiming to concentrate metals (especially copper and gold) and extract iron, which is prejudicial to copper bioleaching. Printed as acids and the need for installations and qualified operators make the process costly [14][15][16]. ...
... The utilization of microorganisms for the recovery of metals is a relatively economic process for recovering precious metals from secondary resources (Garlapati, 2016;Sun et al., 2016). Biohydrometallurgical processing is an alternate route for the recovery of metals, specifically, from low-grade and lean grade ores, shales and secondary resources (Anjum et al., 2012). ...
Article
The growing population and increased disposal of end-of-life (EoL) electrical and electronic products have caused serious concerns to the environment and human health. Electronic waste (e-waste) is a growing problem because the quantity and the rate at which it is generated has increased exponentially in the last 5 years. The rapid changes or upgradation in technologies, IT requirements for working or learning from home during COVID-19, manufacturers releasing new electronic gadgets and devices that serves the consumers comfort and a declension in services has contributed to an increase in the e-waste or waste of electrical and electronic equipment (WEEE) generation rates. The current status of e-waste generation, handling procedures and regulatory directives in USA, EU, China, India, Vietnam and Gulf Cooperation Council (GCC) countries are presented in this review. The recent developments in e-waste recycling methods/recovery of base and precious metals, the advantages and limitations of hydrometallurgy, pyrometallurgy, biohydrometallurgy and pyrolysis are discussed. Considering the impediments in the present technologies, the extraction of valuable resources, i.e. precious metals, from e-waste using suitable biocatalysts shows promising applications. This review also stresses on the research needs to assess the economic effects of involving different unit operations/process industries for resource recovery, reuse and recycling.
... Bio washing is another type of hydrometallurgical process that uses metabolites secreted by microorganisms to dissolve waste electrode materials and extract valuable metals [286,287]. Some bacteria and fungi may contain metals from used LIBs. ...
Article
In the context of constant growth in the utilization of the Li-ion batteries, there was a great surge in the quest for electrode materials and predominant usage that lead to the retiring of Li-ion batteries. This review focuses on the recent advances in the anode and cathode materials for the next-generation Li-ion batteries. To achieve higher power and energy demands of Li-ion batteries in future energy storage applications, the selection of the electrode materials plays a crucial role. The electrode materials, such as carbon-based, semiconductor/metal, metal oxides/nitrides/phosphides/sulfides, determine appreciable properties of Li-ion batteries such as greater specific surface area, a minimal distance of diffusion, and higher conductivity. Various classifications of the anode materials such as the intercalation/de- intercalation, alloy/de-alloy, and various conversion materials are illustrated lucidly. Further, the cathode materials, such as nickel-rich LiNixCoyMnzO2 (NCM), were discussed. NCM members such as NCM 333, NCM 523 that enabled to advance for NCM622 and NCM81are reported. The nanostructured materials bridged the gap in the realization of next-generation Li-ion batteries. Li-ion batteries’ electrode nanostructure synthesis, performance, and reaction mechanisms were considered with great concern. The serious effects of Li-ion batteries disposal need to be cut significantly to reduce the detrimental effect on the environment. Hence, the recycling of spent Li-ion batteries has gained much attention in recent years. Various recycling techniques and their effect on the electroactive materials are illustrated. The key areas covered in this review are anode and cathode materials and recent advances along with their recycling techniques. In light of crucial points covered in this review, it constitutes a suitable reference for engineers, researchers, and designers in energy storage applications.
... To date, the annual global demand for rare metals has not yet exceeded the annual supply volume, which varies from 120,0 0 0 to 140,0 0 0 tons ( Klinger, 2018 ). In recent decades, resources of highquality ores have been significantly depleted, forcing the industry to look for alternative sources of raw materials ( Anjum et al., 2012 ;Sethurajan et al., 2017 ). Oils, coals and solid wastes can be considered as such sources ( Salgansky et al., 2019 ). ...
Article
In this paper, the heterogeneous combustion of porous metal-containing media is studied taking into account the phase transitions of metal in condensed and gas phases. Such process takes place when applying a novel promising method for the extraction of rare metals from various combustible materials, such as coal and petroleum wastes, by means of filtration combustion. A novel mathematical model, based on the conservation laws, is developed for investigating the physicochemical and gas-dynamic processes during the propagation of combustion waves in porous media with admixtures of metals. Using numerical experiments, the possibilities of metal mass transfer and accumulation of condensed metal in a narrow zone of the porous reactor are shown. The effect of the gas velocity at the reactor inlet and initial metal concentration on combustion of porous metal-containing media is studied. It is revealed that by changing the gas velocity at the reactor inlet, it is possible to control the process of metal transfer and accumulation during the extraction of rare metals from various combustible media. It is shown that the investigated method of rare metals extraction can be very effective for combustible media with a low initial metal concentration.
... Proses recovery logam menggunakan teknik leaching dengan prinsip kerja yaitu pelarut akan melarutkan sebagian bahan padatan sehingga bahan pelarut yang diinginkan diperoleh setelah itu dilakukan proses pemisahan larutan yang terbentuk dari padatan sisa [1]. Kebanyakan proses leaching dilakukan dengan menggunakan asam kuat sehingga dapat menimbulkan ancaman terhadap lingkungan (limbah berbahaya) [2]. ...
Article
Perkembangan teknologi tidak serta merta memberikan dampak yang selalu positif. Sebagai contoh, seiring meningkatnya produk-produk portable maka kebutuhan baterai akan meningkat secara signifikan. Hal tersebut justru akan menambah jumlah limbah baterai. Konsumen membuang ratusan bahkan jutaan limbah baterai pertahunnya yang mengandung bahan beracun dan korosif ke lingkungan begitu saja. Oleh karena itu, perlu ada treatment untuk mengolah limbah baterai, salah satunya adalah dengan merecovery logam yang terkandung dalam baterai. Bioleaching merupakan suatu proses ekstraksi logam yang dilakukan dengan bantuan bakteri atau jamur yang mampu mengubah senyawa logam yang tidak dapat larut menjadi senyawa logam yang dapat larut dalam air melalui reaksi biokimia. Pada Proses bioleaching, jamur berperan menghasilkan asam organik yang mampu melarutkan logam. Tujuan penelitian ini adalah mengetahui pengaruh adaptasi mikroorganisme pada litium terhadap jumlah akumulasi litium dan membandingkannya dengan akumulasi litium tanpa adanya adaptasi mikroorganisme. Jamur yang digunakan adalah Aspergillus niger dan limbah baterai yang digunakan adalah baterai laptop bekas. Perbandingan dapat ditunjukkan dari hasil bioleaching litium dengan proses adaptasi yaitu sebesar 80% litium terleaching, sedangkan untuk hasil bioleaching litium tanpa proses adaptasi hanya sebesar 58% litium terleaching.
... Chemical analysis of the main metal elements content in each size fraction showed that the total metals remained in the residue is up to about 7% (Fig. 2). The main metal elements in the residue are Cu (0.91%), Al (3.05%), Ca (1.85%), Mg (0.19%), B (0.19%), Fe (0.13%) and Sn (0.03%), which was similar with low grade ores (Anjum et al., 2012). The residual metal content increased from 4.46% to 8.62% with a decrease in particle size, agree with previous reports (Haifeng Wang et al., 2018). ...
Article
Metals removal from industrial process residues is essential to alleviate the potential threat to environment and avoid the resource waste. Because of very low concentration of metals and complexity of residues, conventional pyrometallurgical and hydrometallurgical routes suffer high cost and uncompleted removal. Here acid catalysis coupling bioleaching strategy was proposed for cost-efficient cleaning of metals from waste resin powder by applying double stress adapted consortium. The results showed that low pH bioleaching significantly improved the metals release, near 100% metals was leached out and no impurities of Fe(III)-precipitates was present in bioleached residue at pulp density of 10% and pH 0.7, which indicated the positive effects of acid in bioleaching of waste resin powder. Economic analysis exhibited that more profits of 33.7 $/t and 56.2 $/t residue were obtained respectively from metals recovery in case of pH 0.7 bioleaching compared with bioleaching at pH 1.5 and acid leaching at pH 0.7. Further stirring bioleaching and static leaching showed similar metals extraction rate under high pulp density conditions and TCLP tests indicated all bioleached residues could be reused as nonhazardous materials safely. However, static bioleaching showed higher ferric iron regeneration capacity and more stable community composition. These findings demonstrated that static low pH bioleaching might be more feasible for treatment of solid waste in full-scale applications from a technological and economical perspective.
... Crundwell, 2013), and we currently do not aim to provide a full overview of their content. There are several dedicated reviews providing overviews of the bioleaching of lean-grade polymetallic ores such as black shales in a wider context (Akcil, 2004a,b;Anjum et al., 2012;Kaksonen et al., 2020;Mahmoud et al., 2017;Mishra and Rhee, 2014;Watling, 2015). Several dedicated projects have been carried out, some of them with demonstrated economic success, such as BioMine (Morin et al., 2006), BioShale (D'hugues et al., 2008), ProMine (Spolaore et al., 2010), EcoMetals (Kutschke et al., 2015), and BIOMOre (Filippov et al., 2017) regarding innovative biohydrometallurgical processes. ...
Article
The aim of this paper is to provide geologists, metallurgical engineers, or mineral resource strategists with a first overview of the currently available state-of-the-art knowledge of the extraction of key metallic values from black shales. The key metallic values considered were vanadium (V), molybdenum (Mo), uranium (U), nickel (Ni), zinc (Zn), as well as platinum group elements and gold. First, a global geological and mineralogical overview is given. Following this, each technological approach is explained and, finally, a summary is provided. Each topic also includes brief overview of the possible environmental impacts. All information was sourced from academic papers, patents, and technological reports. The main conclusions are: (i) black shales are enriched in different sets of metals, yet the V-Mo-U-Ni-Zn association is relatively universal, (ii) mineralization is mostly disseminated and rocks are very fine grained, (iii) hosts of key metals are either sulfides of organometallic complexes, V is often associated with silicates, (iv) the latter 3 along with additional factors result in poor opportunities for beneficiation (flotation, etc.), (v) extraction methods range from conventional hydrometallurgy, bio-leaching, and in-situ leaching in many combinations with roasting, microwave, autoclave or other aiding steps. The final choice of technology is site-specific and there are no rule-of-thumb solutions. There is only one fully operational production unit that exploits black shale as a raw material – Talvivaara/Terrafame in central Finland.
... The increase in demand for nuclear power has resulted in progressive exhaustion of high-grade uranium reserves [3][4][5]. To accommodate the demand for this limited resource, it is necessary to develop new methods for exploiting the low-grade and refractory uranium ore [5][6][7][8][9]. Biohydrometallurgy technology is widely recognized as a new technology for extracting metals from the complex, refractory and low grade ore [10][11][12][13]. ...
Article
Full-text available
In order to optimize conditions for bioleaching of the high-fluorine and low-sulfur uranium ore by the test acidophilic consortiums, the central composite design method and response surface method were applied to study the relationships between pyrite addition, pulp density, temperature and uranium recovery rate, respectively. The results showed that the pulp density, pyrite addition and temperature had a significant impact on the uranium recovery rate. The predicted optimum uranium leaching conditions were 2.20% of pyrite addition, 7.69% of pulp density and 31.90 °C of temperature, respectively. The actual uranium leaching rate under the optimal conditions was 94.84%, which was consistent with the predicted values with the model (95.21%). The results were of great significance for a large-scaled bioleaching practice of the high-fluorine and low-sulfur uranium or low-grade uranium ore.
... The biomining strategy, which takes advantage of microorganisms' bioleaching activities, is one such intervention. Several authors agree that the potential benefits of bioleaching in the exploitation of low-grade ores will be significant, particularly in addressing challenges identified by the use of conventional methods [15,63,[129][130][131]. To support this claim, studies comparing the metal extraction efficiency of chemical and bioleaching methods have been conducted. ...
Article
Full-text available
Mining has advanced primarily through the use of two strategies: pyrometallurgy and hydrometallurgy. Both have been used successfully to extract valuable metals from ore deposits. These strategies, without a doubt, harm the environment. Furthermore, due to decades of excessive mining, there has been a global decline in high-grade ores. This has resulted in a decrease in valuable metal supply, which has prompted a reconsideration of these traditional strategies, as the industry faces the current challenge of accessing the highly sought-after valuable metals from low-grade ores. This review outlines these challenges in detail, provides insights into metal recovery issues, and describes technological advances being made to address the issues associated with dealing with low-grade metals. It also discusses the pragmatic paradigm shift that necessitates the use of biotechnological solutions provided by bioleaching, particularly its environmental friendliness. However, it goes on to criticize the shortcomings of bioleaching while highlighting the potential solutions provided by a bespoke approach that integrates research applications from omics technologies and their applications in the adaptation of bioleaching microorganisms and their interaction with the harsh environments associated with metal ore degradation.
... Fungal systems would not compete with prokaryotic systems in this context, but it is important to assess fungal interactions with sulfide, and other, minerals to throw light on the range of possible interactions in an environmental context and to complete geomicrobiological understanding. Previous research on bacterial chemoorganotrophic leaching of sulfide minerals in black shale by Bacillus strains was found to be in the following order of efficiency: pyrrhotite (Fe 1Àx S) > sphalerite (ZnFe) S > galena (PbS) > Ni-sulfide (NiFe) Xs > (NiFe) S 2 > Cu-sulfide (Cu 2 S, CuS, CuS 2 ) > chalcopyrite (CuFeS 2 ) > pyrite (FeS 2 ) > arsenopyrite (FeAsS) ( Anjum et al. 2012;Farbiszewska-Kiczma et al. 2004). Laterite ores in tropical areas are a significant, unexploited pool of Co at present ( Smith et al. 2017). ...
Article
The bioleaching efficiency and mechanism of recovery of cobalt (Co) and nickel from laterites and pyritic ores by Aspergillus niger were investigated. Recoveries of Co from laterites and pyritic ores by direct bioleaching were 65.9 ± 1.8% and 4.9 ± 2.7%, respectively, while 30.9 ± 0.6% and 10.9 ± 6.2% recovery of Ni were obtained from laterites and pyritic ores, respectively. Recovery of Co via indirect bioleaching in the absence of the fungal biomass from laterite was significantly lower when compared with Co released by direct bioleaching. In the latter, hyphal penetration and colonization of the laterites were clearly observed by scanning electron microscopy (SEM). X-ray powder diffraction (XRPD) analysis of mineral phases before and after bioleaching indicated that cobalt-bearing goethite was the main phase bioleached in the laterites. No significant difference was found between Co recoveries from synthesized cobalt-bearing goethite by both direct and indirect bioleaching. Therefore, we propose that two processes are involved in bioleaching from laterites: (1) cobalt-bearing goethite was exposed via direct interactions between the fungus and the minerals and (2) cobalt-bearing goethite was dissolved by released metabolites of A. niger, such as organic acids. An incongruent pattern of Co and Fe bioleaching from the laterites was also a feature of the metal recovery process.
... 8 It has been successfully implemented to extract secondary copper sulde minerals. 9,10 There are many bioleaching microorganisms such as A. ferrooxidans, L. ferrooxidans, Acidithiobacillus caldus (A. caldus), and Sulfobacillus thermosuldooxidans (S. thermosuldooxidans). A. ferrooxidans is one of the most commonly used species in bio-dissolution or biomineralization; it is frequently observed in nature and is present in sulde minerals such as pyrite, coal mines, and also in acid mine drainage. ...
Article
Full-text available
Marmatite and bornite are commonly associated together in nature, and their interactions in an acidic environment are vital for both (bio)hydrometallurgy and acid mine drainage (AMD) production. In this work, dissolution experiments (marmatite : bornite = 2 : 0, 3 : 1, 1 : 1, 1 : 3 and 0 : 2) accompanied by analytic techniques such as electrochemical methods, Raman spectroscopy and synchrotron radiation-XRD (SR-XRD) were utilized to interpret the interactions between marmatite and bornite in acidic abiotic and biotic systems. The dissolution experiments showed that marmatite can significantly accelerate the oxidative dissolution of bornite, especially in the abiotic system. On the contrary, bornite inhibited the oxidative dissolution of marmatite when the percentage of bornite was high. Electrochemical measurements proved that the galvanic interactions between marmatite and bornite were slight and should not be the main cause for the interactions. Combined with the dissolution experiments, analytic techniques and previous references, it could be speculated that marmatite accelerated bornite dissolution mainly by providing an iron source, which acted as the energy source for microorganisms and oxidants. Bornite affected the dissolution of marmatite mainly by Cu2+ ions dissolving from bornite. Bornite inhibited the oxidative dissolution of marmatite mainly because a high Cu2+ concentration could significantly hinder marmatite dissolution. In addition, the formation of elemental sulfur or jarosite was also one important cause. Bornite intensified marmatite dissolution when the percentage of bornite or the Cu2+ concentration was extremely low and then, a synergic dissolution process occurred.
... Bio washing is another type of hydrometallurgical process that uses metabolites secreted by microorganisms to dissolve waste electrode materials and extract valuable metals [286,287]. Some bacteria and fungi may contain metals from used LIBs. ...
Article
Full-text available
In the context of constant growth in the utilization of the Li-ion batteries, there was a great surge in the quest for electrode materials and predominant usage that lead to the retiring of Li-ion batteries. This review focuses on the recent advances in the anode and cathode materials for the next-generation Li-ion batteries. To achieve higher power and energy demands of Li-ion batteries in future energy storage applications, the selection of the electrode materials plays a crucial role. The electrode materials, such as carbon-based, semiconductor/metal, metal oxides/nitrides/phosphides/sulfides, determine appreciable properties of Li-ion batteries such as greater specific surface area, a minimal distance of diffusion, and higher conductivity. Various classifications of the anode materials such as the intercalation/de- intercalation, alloy/de-alloy, and various conversion materials are illustrated lucidly. Further, the cathode materials, such as nickel-rich LiNixCoyMnzO2 (NCM), were discussed. NCM members such as NCM 333, NCM 523 that enabled to advance for NCM622 and NCM81are reported. The nanostructured materials bridged the gap in the realization of next-generation Li-ion batteries. Li-ion batteries’ electrode nanostructure synthesis, performance, and reaction mechanisms were considered with great concern. The serious effects of Li-ion batteries disposal need to be cut significantly to reduce the detrimental effect on the environment. Hence, the recycling of spent Li-ion batteries has gained much attention in recent years. Various recycling techniques and their effect on the electroactive materials are illustrated. The key areas covered in this review are anode and cathode materials and recent advances along with their recycling techniques. In light of crucial points covered in this review, it constitutes a suitable reference for engineers, researchers, and designers in energy storage applications.
Article
The mixed extractants are promising for the separation of complex multi-metal solutions due to their specific intermolecular interaction. In this work, the mixtures of Cyanex302 (C302) and Cyphos IL101 (IL101) were used to separate Cu(II)/Co(II) by adjusting the mole fraction of IL101 (XIL101) and the separation factor of copper over cobalt can be improved compared with the individual C302. The FT-IR combined with NMR analysis indicated that the dimeric C302 can completely dissociate at XIL101 > 0.3 and form C302-IL101 adduct due to their molecular interactions. Based on the two-dimensional correlation analysis of IR spectra (2D-COS IR), four molecular environments of the P-OH group can be found in the mixed systems with varied XIL101, including C302 monomer, C302 dimer, IL101-C302 adduct, adduct of C302 with IL101 ion clusters. Although these formed adducts present an anti-synergism for the extraction of metal ions, the separation of Cu over Co can be greatly improved because the co-extraction of Co is evidently depressed. Small-angle X-ray scattering analysis showed that the aggregates of individual IL101 and C302 systems have a similar ellipsoid morphology with different sizes, whereas the mixtures of IL101 and C302 present a spherical structure. These results will be helpful for the design of efficient extractants for the complex separation systems.
Chapter
With the pursuit of high energy-density and low cost lithium-ion batteries (LIBs), cobalt content in the cathode materials decreases gradually. In addition, the limited nature of lithium mineral reserves is a prominent issue as the demand for LIBs is expanding fast. Hence, traditional pyrometallurgical methods is not competent to recycle spent LIBs, because not only their economic efficiency strongly depends on the cobalt content, but also they cannot recover lithium from spent LIBs. Bio-hydrometallurgical methods for recycling spent LIBs have been proposed and attracted increasing attentions in the past decades. These methods involve biological processes in which some metabolites excreted by microorganisms are used for extraction of metals from spent LIBs. Bio-hydrometallurgy, which is a special kind of hydrometallurgy, has its unique advantages and disadvantages due to the use of living biomass. This chapter gives an overview of this method in terms of leaching mechanisms, impacts on leaching efficiency and pros and cons of it.
Chapter
A mature technology of lithium-ion batteries (LIBs) is applied in various electronic devices. The wide application of LIBs has brought large quantities of spent batteries, which has become a global problem. Owing to unfavorable effects of spent LIBs on the economic and environmental aspects, much effort has been made in many countries to manage and recycle the waste batteries. Owing to several restrictions in conventional recycling methods, the use of microorganisms has attracted increasing attention. The bio-hydrometallurgical approaches realize the win-win situation of environmental and economic benefits. In this chapter, the information available on the basic principles and recent developments of the bioleaching of metals from LIBs are reviewed in detail. Additionally, this chapter gives an overview of the previous studies performed in this field. Furthermore, the challenges, limitations, and potential solutions for applying more efficient bioleaching approach for recovery of metals from LIBs are highlighted.
Article
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This article presents the results of a study of sorption extraction of molybdenum from sulfate solutions obtained by leaching black-shale ores of Big Karatau. For the extraction of molybdenum was used the method of ion exchange weakly basic anion exchange resin Lewatit MP62W5. The study determined the optimal conditions for the sorption and desorption processes of molybdenum, which included factors such as pH, the duration of the process and the concentration of the necessary reagents. To study the optimal parameters of sorption extraction of molybdenum, the same anion-exchange resin Lewatit MP62W5 was used at a concentration of 0.073 g/l of molybdenum in initial solutions. Application of this anionite for 48 hours during the sorption process and increasing the pH to 5.5 leads to sorption of more than 88 % of the molybdenum from the solution. A solution of ammonium sulfate was used for desorption of molybdenum from saturated resins. It was found that the optimal duration of the molybdenum desorption process is 4 hours at a concentration of (NH4)2SO4 150 g/l. The degree of desorption in this case was 93-94 %
Chapter
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The rising production of lithium-ion batteries (LIBs) due to the introduction of stationary and portable energy-storage devices as well as electric mobility in particular demands an efficient and sustainable waste management scheme. In principle, the material transformation from end-of-life (EOL) LIBs to secondary (raw) materials follows the recycling chain for wastes. Therein, processing aims to break up the bonds between the individual components and materials of the battery to enrich them into defined concentrates for subsequent metallurgical refining. In general, mechanical processes are more energy-efficient and economically affordable than thermal, chemical, and metallurgical ones. Consequently, a combination of several crushing, size classifying, and sorting steps are commonly used to prepare concentrates for further treatment. This chapter presents the principles of mechanical liberation and physical separation processes for EOL LIB processing. Combinations of specific processes categorized by their feed materials are proposed and discussed, outlining possible material fractions and further potential for research and development. LIB recycling with a mechanical processing unit is shown to achieve high recycling efficiencies that enable the fulfill the upcoming and updated European legal framework regarding LIB disposal.
Article
In this work is evaluated the bioleaching capacity of a bacterium isolated from a mine in Guanajuato, México, namely LR-1. The bacterium oxidized Fe2+ and S2O32- at acidic pH for its energy metabolism. This oxidant activity provided Fe3+ and/or protons that provoke sulfide ore dissolution. Five sulfide ore samples were obtained from different Mexican mines: Remedios, Guerrero, Bolañitos, Aldama, and Ocampo. The Ag, Cr, Cu, Fe, Pb, and Zn contents in the ores was analyzed by atomic absorption. Other physicochemical properties, including pH, electrical conductivity, and oxide-reducing potential, were also measured. Bioleaching was evaluated by metal concentration in the medium due to bacterial growth developed in basal salt medium with 2% (w/v) mineral in acidic conditions at 37°C. There was an increase in the percentage release of Ag (18.66% to 29.85%), Cu (60.90% to 73.66%), and Cr (11.71% to 15.04%), with respect to chemical leaching, mainly from the Remedios ore. A phylogenetic analysis of the 16S rRNA gene sequences revealed that bacterium LR-1 belongs to the genus Brevibacillus. There are no known species from this genus related with the leaching processes. This is the first report of an acidophile chemolithoautotrophic iron oxidizing bacterium from the genus Brevibacillus in the metal bioleaching. Therefore, these data contribute to the knowledge of the hydrometallurgical microbiology.
Article
Waste will become the major resource in the future circular economy. In particular, E-waste is a major sector growing at an annual rate of about 2 million tonnes (Mt) with rising users of electrical and electronic items worldwide. This is a consequence of versatility and affordability of technological innovation, thus resulting in massive sales and e-waste increases. Most end-users lack knowledge on proper recycling or reuse, often disposing of e-waste as domestic waste. Such improper disposals are threatening life and ecosystems because e-waste is rich in toxic metals and other pollutants. Here we review e-waste generation, policies and recycling methods. In 2019, the world e-waste production reached 53.6 Mt, including 24.9 Mt in Asia, 13.1 Mt in USA, 12 Mt in Europe. In Asia, China (10.1 Mt), India (3.23 Mt), Japan (2.57 Mt) and Indonesia (1.62 Mt) are the largest producers contributing to about 70% of the total world e-waste generated. Only 17.4% (9.3 Mt) of the world e-waste was recycled by formal means, and the remaining 82.6% (44.3 Mt) was left untreated or processed informally. As a consequence, most countries have framed policies to provide regulatory guidelines to producers, end-users and recyclers. Yet the efficiency of these local policies are limited by the transfer of products across borders in a globalized world. Among formal recycling techniques, biohydrometallurgy appears most promising compared to pyrometallurgy and hydrometallurgy, because biohydrometallurgy overcomes limitations such as poor yield, high capital cost, toxic chemicals, release of toxic gases and secondary waste generation. Challenges include consumer’s contempt on e-waste disposal, the deficit of recycling firms and technology barriers.
Chapter
Hydrometallurgy is a versatile, flexible, and industrially feasible process to simultaneously address waste battery recycling, e-waste management, and environmental challenges for the circular economy of battery metals and sustainable waste battery recycling. We have developed a closed-loop industrial hydrometallurgical process for valorizing lithium-ion battery (LIB) industry waste for use in battery manufacturing, which is discussed in this chapter. Through a sequential combination of hydrometallurgical techniques like leaching-solvent extract-scrubbing-(precipitation) stripping, a process for 5N pure cobalt recovery from LIB industry waste has been developed. First, cobalt is extracted by acid leaching; then, from the leach liquor, cobalt is separated/purified by solvent extract using saponified Cyanex 272. From cobalt-loaded Cyanex 272, residual lithium is scrubbed by Na2CO3 solution. Finally, cobalt is recovered by precipitation stripping via two routes, (1) as cobalt sulfate and (2) as cobalt oxalate. Cobalt oxide, which can be used in battery production, is synthesized and characterized from the cobalt oxalate. The cobalt oxalate precipitate is calcined to synthesize Co3O4, a precursor for LIB manufacturing. TGA-DTA followed by XRD analysis has confirmed the conversion of CoC2O4·2H2O to anhydrous CoC2O4 at 200°C, anhydrous CoC2O4 to Co3O4 at 350°C, and Co3O4 to CoO at 1100°C. In general, the valorization process can circularize waste LIBs for the LIB manufacturing process through a versatile and flexible industrial approach.
Article
Thermodynamic calculations for describing the compositions of the products formed in conditions of the filtration combustion of the metal-containing mixtures were carried out. The analysis of the equilibrium compositions of the products was carried out using the TERRA high-temperature thermochemical equilibrium calculation program. According to the results of calculations, the metals were divided into two groups. First one forms both the condensed and gaseous phases and in the second one ‒ metals that are only in the condensed phase. In case of the presence of metal compounds in the gas phase, as a rule, these are the following compounds: metals, oxides, hydroxides, hydrides, sulfides and metal sulfates. Metals of the second group cannot be subjected to mass transfer under conditions of the filtration combustion wave and will remain in solid combustion products (in ash).
Article
In chalcocite (Cu2S) bioleaching, the lack of iron metabolism is a key restricting factor. As the most common sulfide mineral, pyrite (FeS2) can release Fe(Ⅱ) and compensate for the iron metabolism deficiency in chalcocite bioleaching. The bioleaching of chalcocite in an imitated industrial system was improved by enhancing the iron–sulfur metabolism simultaneously using pyrite and sulfur oxidizers based on the joint utilization of waste resources, while the bioleaching performance and community structure in the leachate were systematically investigated. Due to the active sulfur/iron metabolism, the pH reached 1.2, and Fe³⁺ was increased by 77.78%, while the biomass of planktonic cells was improved to 2.19×10⁷ cells/mL. Fourier transform infrared reflection (FTIR) and X-ray diffraction (XRD) analysis results showed that more iron–sulfur crystals were produced due to more active iron–sulfur metabolism. Scanning electron microscopy (SEM) revealed that many derivative particles and corrosion marks appeared on the surface of the ore, implying that the mineral–microbe interaction was strengthened. Confocal laser scanning microscopy (CLSM) showed the accumulation of cells and extracellular polymeric substances (EPS) on the ore surface, indicating a stronger contact leaching mechanism. Furthermore, the community structure and canonical correspondence analysis (CCA) demonstrated that the introduction of sulfur-oxidizing bacteria and pyrite could maintain the diversity of dominant leaching microorganisms at a high level. Sulfobacillus (27.75%) and Leptospirllillum (20.26%) were the dominant sulfur-oxidizing and iron-oxidizing bacteria during the bioleaching process. With the accumulation of multiple positive effects, the copper ion leaching rate was improved by 44.8%. In general, this new type of multiple intervention strategy can provide an important guide for the bioleaching of low-grade ores.
Article
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Circular economy is considered a new chance to build a more sustainable world from both the social and the economic point of view. In this Essay, the possible contribution of inorganic chemistry towards a smooth transition to circularity in inorganic materials design and production is discussed by adopting an interdisciplinary approach. Circular economy, acknowledged as “an opportunity to rethink our economic future”, is considered a new chance to build a more sustainable world from both the social and the economic point of view. In this Essay, the perspective contribution of inorganic chemistry towards a smooth transition to circularity in inorganic materials design and production, to enable them to enter into the circular loop, is outlined by adopting a truly interdisciplinary approach, encompassing expertise in inorganic materials chemistry, modelling, materials engineering, circular waste management, metallurgy, and mineralogy.
Article
Black shale-hosted vanadium deposit is an important species of nontraditional mineral resources. The green efficient separation of black shale-hosted vanadium has attracted lots of researchers’ attention. In the paper, two-stage pressurized acid leaching coupled with lixivium recycling was investigated and clarified. Results showed that this coupling technics endowed selective leaching of vanadium under the optimized conditions that were liquid to solid ratio of 1.5 mL/g, leaching time of 120 min, sulfuric acid addition of 12.5 vol%, the first-stage temperature of 180 °C and second-stage temperature of 150 °C. From the first stage to the second stage, the muscovite has been almost dissolved, which guaranteed high vanadium recovery. Through recycling the second-stage lixivium, the first-stage pH value was controlled below pHTθ of Eq.5 (0.27, 180°C) and above pHTθ of Eq.6 (-0.88, 180°C) and Eq.7 (-2.83, 180°C), triggering the isomorphous precipitation of Fe and Al as kalunite-jarosite solid solution. Once fresh sulfuric acid solution touched the first-stage residue, the kalunite-jarosite solid solution can still be stably remained and discharged. The leached Fe and Al ions were directionally gathered to the first stage and precipitated as kalunite-jarosite solid solution. Recent data collected from this coupling technics suggests that the asynchronous dissolution-precipitation of V, Al and Fe was achieved during acid leaching of the black shale.
Article
Owing to industrial evolution, a huge mass of toxic metals, including Co, Cu, Cr, Mn, Ni, Pb, and Zn, and metalloids, such as As and Sb, has inevitably been released into the natural environment and accumulated in soils or sediments. Along with modern industrialization, many mineral mines have been explored and exploited to provide materials for industries. Mining industries also generate a vast amount of waste, such as mine tailings, which contain a high concentration of toxic metals and metalloids. Due to the low economic status, a majority of mine tailings are simply disposed into the surrounding environments, without any treatment. The mobilization and migration of toxic metals and metalloids from soils, sediments, and mining wastes to water systems via natural weathering processes put both the ecological system and human health at high risk. Considering both economic and environmental aspects, bioleaching is a preferable option for removing the toxic metals and metalloids because of its low cost and environmental safety. This chapter reviews the recent approaches of bioleaching for removing toxic metals and metalloids from soils, sediments, and mining wastes. The comparison between bioleaching and chemical leaching of various waste sources is also discussed in terms of efficiency and environmental safety. Additionally, the advanced perspectives of bioleaching for environmental remediation with consideration of other influencing factors are reviewed for future studies and applications.
Article
Biological column leaching of Ni from low-grade Ni ore was studied, and the effects of ore particle size on leaching rate were investigated. The Ni ore with an average Ni content of 0.23% was crushed into four different particle size fractions: >10 mm, 5–10 mm, 2–5 mm and <2 mm. The main strain components at the genus level were acidithiobacillus (53.11%), leptospirillum (43.52%), and acidiphilium (3.37%). The leaching tests were carried out at pH 2.0 and ∼23°C. The Ni leaching rates from ores with particle sizes >10 mm (bioleaching), 5–10 mm (acid leaching), 5–10 mm (bioleaching), and 2–5 mm (bioleaching) were 23.76%, 22.15%, 32.42% and 54.17%, respectively, after 180 d of bioleaching. The ore particle size changed after leaching, compared with the original ore size, the proportion of the same size of 2–5 mm ore decreased to 44.64%. Ore with particle size of 2–5 mm was most suitable for column bioleaching, and effective Ni extraction was achieved with appropriate control of ore granularity.
Chapter
Bioleaching is an eco-friendly and cost-effective technology for processing low-grade and complex ores and may also be an important bioremediation technology for processing solid waste and secondary resources such as tailings, electronic waste, spent catalyst, sludge, sediment, fly ash, and smelter waste. However, large-scale commercial applications of chalcopyrite bioleaching, especially heap bioleaching of chalcopyrite, are still developing slowly owing to the refractory nature of chalcopyrite. Some industrial practice cases of chalcopyrite bioleaching are summarized in this chapter, which provides a reference for its future industrial application. Key parameters and controlling techniques for chalcopyrite bioleaching, mainly including redox potential/oxidation-reduction potential, pH, temperature, and additives, are summarized and discussed.
Article
Surface pretreatment on minerals prior to flotation was proved to increase the selectivity of separation process. Organic acid pretreatment of low-grade diasporic-bauxite was conducted, and the effects of oxalic acid on bauxite flotation were investigated in this work. The oxalic acid pretreatment mechanisms were studied by adsorption measurements, zeta potential testing, XPS analysis, and ICP analysis. The flotation results showed that the oxalic acid treatment could significantly improve Al2O3 recovery from 75.39% to 81.88% and decrease SiO2 recovery from 53.26% to 47.30%. The adsorption capacity of diaspore for sodium oleate (NaOL) increased by 8.50%, while that of kaolinite decreased by 11.72%. XPS analysis revealed that oxalic acid treatment improved the relative contents of unsaturated Al at diaspore surface beneficial to the adsorption of NaOL. While the relative contents of Al at kaolinite surface was decreased due to the Al dissolution revealed by ICP results. Zeta potential analysis indicated that oxalic acid changed the surface property of minerals favorable for the selective adsorption of NaOL on diaspore surface rather than kaolinite surface. These findings provided a promising direction for surface pretreatment of low-grade bauxite using oxalic acid for the improvement of the flotation desilication.
Article
Mineralogical study showed that the Yuejin uranium ore is from a low grade, high carbonate and high pyrite sandstone type uranium deposit. Uranium leaching rate, uranium speciation of leachate, leaching kinetics and precipitation analysis were investigated under the conditions of different acidity, liquid–solid ratio and H 2 O 2 concentration. The test results showed that the weak acid leaching process can be used to develop high carbonate type uranium deposits, however, because of the high content of pyrite, other oxidants except high concentration H 2 O 2 need to be considered.
Chapter
Batteries, especially lithium-ion batteries, have a growing market and are distributed worldwide. Therefore, waste management is a primary challenge when their lives end. Battery recovery and reuse produce economic profits and protect the environment. Presently, industries tend to use green methods such as bioleaching for their more economical labor and energy requirements, favorable capital investment, reduced risk, higher operating levels, limited industrial requirements, and mild reaction conditions. The ultimate goal of recycling spent battery materials is their regeneration into new materials. Scientists have focused primarily on the recovery, separation, and purification (e.g., solvent extraction and chemical precipitation) of valuable metals from leachate. The topics discussed in this chapter are biohydrometallurgical techniques for recovering valuable metals from spent batteries, the resynthesis methods for these metals, and their return to battery production industries.
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Citric acid (CA) production by Aspergillus niger ATCC9642 from whey with different concentrations of sucrose, glucose, fructose, galactose riboflavin, tricalcium phosphate and methanol in surface culture process was studied. It was found that whey with 15% (w/v) sucrose with or without 1% methanol was the most favourable medium producing the highest amount (106.5 g/l) of citric acid. Lower CA was produced from whey with other concentrations of sugars and other additives used. Highest biomass of A. niger was produced with the addition of riboflavins. In general, extension of the fermentation (up to 20 days) resulted in an increase in CA and biomass, and decrease in both residual sucrose and pH values.
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The origin of a rational (scientific) approach to extraction of metal values from ores with the aid of microorganisms (bioleaching) is traced. The removal by microbiological means of ore constituents that interfere with metal extraction (biobeneficiation), an outgrowth from bioleaching, is also traced. © 2004 SDU. All rights reserved.
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In certain areas of Varanasi city, waste water from Dinapur sewage treatment plant is used for irrigating vegetable plots. We quantified the concentrations of heavy metals, viz. Cd, Cr, Cu, Ni, Pb and Zn in soil, vegetables and the waste water used for irrigation. The waste water used for irrigation had the highest concentration of Zn followed by Pb, Cr, Ni, Cu and Cd. Continuous application of waste water for more than 20 years has led to accumulation of heavy metals in the soil. Consequently, concentrations of Cd, Pb and Ni have crossed the safe limits for human consumption in all the vegetables. Percent contribution of fruit vegetables to daily human intake for Cu, Ni, Pb and Cr was higher than that of leafy vegetables, while the reverse was true for Cd and Zn. Target hazard quotient showed health risk to the local population associated with Cd, Pb and Ni contamination of vegetables. Therefore, to reduce the health risk and the extent of heavy metal contamination, steps must be taken for efficient treatment of sewage. Regular monitoring of heavy metals in the vegetables grown in waste water irrigated areas is also necessary.
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A 3-phase computational ∞uid dynamics (CFD) model for heap bioleaching of chalcocite is investigated to identify and understand the efiect of oxygen ∞ow during air sparging. The study uses an existing one-dimensional model of liquid ∞ow, bacterial transport (including attachment/detachment of bacteria to ore particles), and the depletion of a copper-sulphide, coupled with a two-dimensional (2D) model of gas ∞ow in the heap. The CFD model includes the efiects of oxygen and ferrous ion consumption, coupled with leaching of copper-sulphide via a shrinking core model. The model is used to investigate the 2D efiects of air ∞ow in heap bioleaching with regard to oxygen limitation.
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Ultrasound can be used for leaching application to increase both dissolution (reaction) rates and yields of products (metal values). Faster process kinetics and reduced reagent consumption could be claimed as the main advantages of the suggested approach. The influence of ultrasound on the leaching process has a direct bearing on the dissipated acoustic power per unit volume rather than on the acoustic intensity, expressed as Wcm. For the overall process the yields are higher and the working conditions are mild (lower temperature, shorter procedure) with selectivity. Mechanism has been hypothesised by the present investigators for understanding the enhanced leaching using ultrasound over and above conventional leaching. Some experimental details in ultrasonic reactors of laboratory scale are discussed. After summarising the benefits of ultrasound leaching, the future prospects of industrial ultrasonic reactors for leaching application are described.
Article
Acidophilic microorganisms are distributed throughout the three domains of living organisms. Within the archaeal domain, both extremely acidophilic Euryarchaeota and Crenarchaeota are known, and a number of different bacterial phyla (Firmicutes, Actinobacteria, and Proteobacteria [α, β, and γ subphyla], Nitrospira, and Aquifex) also contain extreme acidophiles. Acidophilic microorganisms exhibit a range of energy-transforming reactions and means of assimilating carbon as neutrophiles. Entire genomes have been sequenced of the iron/sulfur-oxidizing bacterium Acidithiobacillus ferrooxidans and of the archaea Thermoplasma acidophilum, Picrophilus torridus, Sulfolobus tokodaii, and Ferroplasma acidarmanus, and more genome sequences of acidophiles are due to be completed in the near future. Currently, there are four recognized species of this genus that grow autotrophically on sulfur, sulfide, and reduced inorganic sulfur compounds (RISCs). Acidithiobacillus ferrooxidans is the most well studied of all acidophilic microorganisms and has often, though erroneously, been regarded as an obligate aerobe. In both natural and anthropogenic environments, acidophilic microorganisms live in communities that range from relatively simple (two to three dominant members) to highly complex, and within these, acidophiles interact positively or negatively with each other. In a study which examined slime biofilms and snotites that had developed on the exposed surface of a pyrite ore within the abandoned Richmond mine at Iron Mountain, the major microorganisms identified were Leptospirillum spp. (L. ferriphilum and smaller numbers of L. ferrodiazotrophum) and Fp. acidarmanus, Sulfobacillus, and Acidimicrobium/Ferrimicrobium-related species. Using a modified plating technique, the uncharacterized β-proteobacterium can be isolated in pure culture and shown to be a novel iron-oxidizing acidophile.
Article
Bacterial leaching of copper and uranium is practiced under acidic DO NOT CORRECT COPPER ORE TREATMENT Leaching Leaching of copper by fungi; G. M. WENBERG, F. H. ERBISCH, M. E. VOLIN; Trans Soc Mining AIME v 250 n 3 Sept 1971 p 207- 12; Bacterial leaching of copper and uranium is practiced under acidic conditions in environments furnishing sulfur and iron. However, many mineral deposits do not have these conditions; the chalcocite and native copper deposits in Michigan's Upper Peninsula are examples. Species of bacteria and fungi isolated previously from samples taken at the White Pine Copper Co. tailings pond and mine, were screened for solubilization of copper from chalcocite ore and flotation concentrate and from native copper jig concentrate. Certain Penicillium species solubilized significant amounts of copper under neutral to slightly acidic conditions in a carbon and nitrogen- enriched medium. leaching apparently was accomplished by release of metabolites which chelated with the copper. The standardized procedures which were developed in an attempt to maximize copper yield in leaching times of three to five days are described.
Article
Sixty-three strains of microoganisms belonging to 15 genera were tested for their ability to extract elements from kaolinite-hematite-bemite bauxite. Microorganisms increased the overall extraction of the elements into a solution as compared to a sterile control within the following range: mycelial micromycetes, 9.7-165 times; yeasts, 3-11 times, heterotrophic bacteria, 3-10 times. Nitrifying bacteria were not active and only Thiobacillus thiooxidans among thionic bacteria extracted aluminium into a solution. Mycelial mciromycetes and heterotrophic bacteria were more active in the extraction of silicon and iron into a solution; yeasts, in aluminium extraction; some yeast strains, in iron extraction. The possibility of using microorganisms for the enrichment of low-grade bauxites is discussed.
Article
The World Deepwatee Market Forcast predicts a continued growth in the deepwater sector with annual expenditures reaching more than US$20 by the year 2010. The US Energy Informations Administration has predicted that world oil consumption will grow to 115.4 million b/d by the year 2030. Deepwater exploration and production activity is driven by a variety of supply-side and demand-side factors including growth in global energy demand and the lack of new opportunities onshore or in shallow waters. Many deepwater development projects, including ExxonMobil's Erha, Bosi, and Akpo projects, are planned for the period to the year 2010. The North Americal region is expected to account for 25% of deepwater development capex over the 2006-2010 period. The Golden Triangle of deepwater, namely the Africa, Gulf of Mexico, and Brazilian areas, will account for 85% of global deepwater expenditure over the forecast period.
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There is considerable interest in how microbiological processes can affect the behaviour of metal contaminants in natural and engineered environments and their potential for bioremediation. The extent to which microorganisms can affect metal contaminants is dependent on the identity and chemical form of the metal and the physical and chemical nature of the contaminated site or substance. In general terms, microbial processes which solubilize metals increase their bioavailability and potential toxicity, whereas those that immobilize them reduce bioavailability. The balance between mobilization and immobilization varies depending on the metal, the organisms, their environment and physico-chemical conditions.
Article
Oil-shale deposits are found in many parts of the world. They range in age from Cambrian to Tertiary and were formed in a variety of marine, continental, and lacustine depositional environments. The largest known deposit is the Green River oil shale in western United States. It contains an estimated 215 billion tons of in-place shale oil (1.5 trillion U.S. barrels). Total resources of a selected group of oil-shale deposits in 33 countries is estimated at 411 billion tons of in-place shale oil which is equivalent to 2.9 trillion U.S. barrels of shale oil. This figure is very conservative because several deposits mentioned herein have not been explored sufficiently to make accurate estimates and other deposits were not included in this survey.
Article
Microbiological leaching has been used as an alternative approach to conventional hydrometallurgical methods of metals extraction. The main concern of the present study was to develop a feasible and economical technique to microbially recover metals such as Fe, U, Mo, Cu and Mn from black shale ore as well as to study the comparative growth of bacteria in a medium containing salts and ferrous sulphate. The microorganism used in this study was potentially important bacteria like Acidithiobacillus ferrooxidans, utilizing energy from the oxidation of ferrous iron, sulphur and reduced sulphur compounds. During bioleaching study, bacteria oxidize pyritic phase to ferric iron and sulphuric acid in case of samples supplemented with FeS04. The pH of the media decreased and redox potential remarkably increased. In bioleached residues, K-jarosite and gypsum were predominant minerals and phologopite grades to biotite. Dolomite transformed to gypsum. Shake flask technique is feasible as bacterial leaching system.
Article
A process by which ore that has usually been crushed and often agglomerated to be stacked on a prepared containment system is known as heap leaching. They use cyanide as the leachant with feeds that are characterized as oxide gold ores in the case of gold. Sulfuric acid is the only commercialized technology for copper heap leaching, but there has also been some experimentation with other lixiviants like ammonia. Copper oxide ore leaching is just about dissolution process but sometimes need a mix of dissolution and bioleaching, where the bioleaching makes the copper available to acid leaching. In the case of nickel laterite ores, heap leaching them is more complicated than copper or gold ores.
Article
Microorganisms are intimately involved in metal biogeochemistry with a variety of processes determining mobility, and therefore, bioavailability. The balance between mobilization and immobilization varies depending on the organisms involved, their environment and physicochemical conditions. Metal mobilization can arise from a variety of leaching mechanisms, complexation by metabolites and siderophores, and methylation, where this results in volatilization. Immobilization can result from sorption to biomass or exopolymers, transport and intracellular sequestration or precipitation as organic and inorganic compounds, e.g., oxalates (fungi) and sulfides. In addition, reduction of higher valency species may effect mobilization, e.g,, Mn(IV) to Mn(II), or immobilization, e.g., Cr(VI) to Cr(III). In the context of bioremediation, solubilization of metal contaminants provides a means of removal from solid matrices, such as soils, sediments, dumps and other solid industrial wastes. Alternatively, immobilization processes may enable metals to be transformed in situ and are particularly applicable to removing metals from aqueous solution. This contribution will outline selected microbiological processes which are of significance in determining metal mobility and which have actual and potential application in bioremediation of metal pollution. These include autotrophic and heterotrophic leaching mechanisms, reductive precipitation, sulfate reduction and metal sulfide precipitation.
Article
Black shales of the basal Lower Cambrian Niutitang Formation, southeast China, host a regionally distributed concordant, several centimeter-thick, sulfide layer which displays extreme metal enrichment, i.e., Mo-Ni-Se-Re-Os-As-Hg-Sb > 1,000 times enriched and Ag-Au-Pt-Pd > 100 times enriched over bulk continental crust. Mineable portions have about 5.5 wt percent Mo, 3.5 wt percent Ni, and 1 g/t PGE + Au. A six-point 187Os/ 188Os versus 187Re/ 188Os isochron on molybdenum-nickel ore samples defines an age of 541 ± 16 Ma (2σ) with an initial 187Os/ 188Os ratio of 0.78 ± 0.19. This age is in agreement with the depositional age of the black shale host; the initial ratio is close to present-day seawater. The sulfide layer/average seawater metal ratio is on the order of 10 6 to 10 8, about 10 to 100 times higher than that for the black shale host and for average metal-liferous black shale. Synsedimentary metal enrichment from seawater under anoxic (sulfate-reducing) conditions appears likely but requires an unsually low sedimentation rate and/or high replenishment rate of fresh seawater to the marine basin. The paleogeographic setting of the Lower Cambrian continental margin of the Yangtze craton indicates local basins controlled by synsedimentary rifting. Stagnant water episodically replenished by upwelling oxidized seawater is thought to be responsible for the formation of the polymetallic sulfide layer and of phosphorite, barite, and sapropelic "stone coal" (combustible black shale) beds.
Article
The degree of carbonate cementation in argillaceous sediments represents one of the significant diagenetic evolutions in ancient mudstones. The alternation of the black shale and laminated limestone of the Lower Jurassic of SW Britain is an example, which typify extent of diagenetic modification of marine clay and organic-rich sediments. The Lower Jurassic mudstones of the SW Britain include black shales, marls and alternate with limestone beds and nodules. Laminated limestones are also present and are only enclosed between the black shales. Detailed petrography combined with geochemical analysis of the black shales and enclosed laminated limestoned have been carried out and compared to the typical isolated nodules in order to interpret the diagenetic history of mudstones. Displacive growth of the microspar crystals was an important process that occurred during the diagenetic evolution of these mudstones. The black shales show carbon (+0.9 to +1.9‰ (PDB)) and oxygen (−2.2 to −4.1‰ (PDB)) isotopic values, which is compared to their enclosed laminated limestones, that show more negative carbon (−0.2 to −1.2 ‰ (PDB)) and oxygen (−5.4 to −6.8‰ (PDB)) values. The stratigraphic position, petrography and isotopic relationship of the black shales and enclosed laminated limestones indicate a degree of diagenetic evolution and carbonate cementation of mustones during progressive burial.
Article
Demand for nickel, largely driven by the Chinese stainless steel market, currently exceeds production, causing an unprecedented rise in the price of nickel and renewed interest in bioleaching technology for the processing of low grade nickel sulfide ores and concentrates. Although nickel inhibits bacterial physiological functions such as iron- and sulfur-oxidation, some bacteria adapt readily to high concentrations. In pilot‐scale continuous reactors, mixed microbial populations grew actively over many months in the presence of up to 400 mM nickel (23 g/L). The results of bench-scale test work have been sufficiently encouraging to prompt pilot- and demonstration-scale trials in heaps and agitated tanks in Australia, China, Finland and South Africa in recent years. The first commercial implementation of nickel sulfide heap leaching is likely to be the operation at Talvivaara, Finland.
Article
Phospholipid ester-linked fatty acids [PFLA] were isolated from a weathering profile developed on Ohio Shale. PLFA distributions were used to describe the microbial communities living in this weathering profile. PLFA are interpreted as mixed aerobic (eukaryote+prokaryote) and anaerobic communities, with a very distinct PLFA distribution at 40–50 cm depth in the core. This depth in the weathering profile corresponds to the onset of shale OM loss and the accumulation of Fe3+ and soil OM. Stable carbon isotopic analysis of PFLA reveals complex patterns of isotopic enrichment and depletion for individual PFLA relative to bulk soil and shale OM. PLFA δ13C values suggest at least some assimilation of shale OM by anaerobic microorganisms. This phospholipids study reveals that weathering profiles developed on black shales are environments of degradation of ancient OM and both accumulation and degradation of more modern soil OM, highlighting the complexity of near-surface microbial processes in sedimentary rocks.
Article
The U.S. steel industry produces approximately 500,000 tons/year of electric arc furnace (EAF) dust, which is classified as a hazardous waste. Increasing disposal costs of these dusts have encouraged studies to investigate treatment processes to render the material non-hazardous, and to possibly recover metal values. This research project was designed to examine the hydrometallurgical recovery of zinc from EAF dusts that have been treated by a double-kiln fuming process. The test work consisted essentially of acidified brine leaching of the pelletized calcine to determine the influence of traditional conditions, such as acid concentration, temperature and agitation, plus the application of ultrasound, on the zinc dissolution efficiency and selectivity.Preliminary leaching tests using acidified calcium chloride indicated that selective leaching of zinc over iron could be attained if ultrasound was employed. The effect of air and nitrogen on the leaching process was investigated and it was established that selective leaching with ultrasound was not dependent upon external agitation or on the availability of oxygen. Without ultrasound, zinc dissolution was enhanced by the presence of oxygen, while iron dissolution was greatly retarded by the absence of oxygen. The role of surface area was examined by pellet grinding and it was demonstrated that selectivity was strongly time dependent and that zinc recovery and iron rejection were enhanced at finer particle sizes.The results of the test work permitted possible mechanisms to be established for the acidified brine leaching process, and it is apparent from the results that ultrasound leaching can significantly improve the selective leaching of zinc from double-kiln treated EAF calcine.
Article
The demand for heavy metals is ever increasing with the advance of the industrialized world, whereas worldwide reserves of high-grade ores are diminishing. However, there exist large stockpiles of low and lean grade ores that are yet to be exploited. In addition, heavy metals that are present in a spectrum of waste streams including mine drainage, industrial effluents, river sediments, electronic scraps and ashes are also available for recovery and utilization. Heavy metal recovery from low and lean grade ores using conventional techniques such as pyrometallurgy, etc. chemical metallurgy encompass several inherent constraints like, high energy and capital inputs, and high risk of secondary environmental pollution. As environmental regulations become ever more stringent, particularly regarding the disposal of toxic wastes, the costs for ensuring environmental protection will continue to rise. Therefore, there is a need to utilize more efficient technologies to recover heavy metals from secondary sources in order to minimize capital outlay, environmental impact and to respond to increased demand. Biohydrometallurgy, which exploits microbiological processes to recover heavy metal ions, is regarded as one of the most promising and revolutionary biotechnologies. The products of such processes are deposited in aqueous solution thereby rendering them to be more amenable to containment, treatment and recovery. On top of this, biohydrometallurgy can be conducted under mild conditions, usually without the use of any toxic chemicals. Consequently, the application of biohydrometallurgy in recovery of heavy metals from lean grade ores, and wastes, has made it an eco-friendly biotechnology for enhanced heavy metal production.
Article
The purpose of this study was to examine structural alterations of finely ground phlogopite, a trioctahedral mica, when exposed to acid, iron- and sulfate-rich solutions typical of bioleaching systems. Phlogopite suspensions were supplemented with ferrous sulfate and incubated with iron- and sulfur-oxidizing bacteria (Acidithiobacillus ferrooxidans) at 22°C. As bacteria oxidized ferrous iron, ferric iron thus formed partially precipitated as K-jarosite. K-jarosite precipitation was contingent on the preceding ferrous iron oxidation by bacteria and the release of interlayer-K from phlogopite. This chemically and microbially induced weathering involved alteration of phlogopite to a mixed layer structure that included expansible vermiculite. The extent of phlogopite weathering and structure expansion varied with duration of the contact, concentration of ferrous iron and phlogopite, and the presence of monovalent cations (NH4+, K+, or Na+) in the culture solution. NH4+ and K+ ions (100mM) added to culture suspensions precipitated as jarosite and thereby effectively prevented the loss of interlayer-K and structural alteration of phlogopite. Additional Na+ (100mM) was insufficient to precipitate ferric iron as natrojarosite and therefore the precipitation was coupled with interlayer-K released from phlogopite. When ferrous iron was replaced with elemental sulfur as the substrate for A. ferrooxidans, the weathering of phlogopite was based on chemical dissolution without structural interstratification. The results demonstrate that iron oxidation and the concentration and composition of monovalent ions can have an effect on mineral weathering in leaching systems that involve contact of phlogopite and other mica minerals with acid leach solutions.
Article
The biosolids industry in Australia is evolving around the beneficial use of biosolids as a resource. Phosphorus rich biosolids from biological nutrient removal (BNR) facilities are highly desirable for land application. However, the accumulation of toxic heavy metals and industrial organic contaminants may render the biosolids unsuitable for land application. The presence of toxic heavy metals has been identified by Local Authorities in Australia as a major constraint limiting the beneficial use of biosolids. The potential of off-site contamination due to the migration of nutrients is also a major concern especially when applying biosolids to acidic agricultural land. Accordingly, the relevant environment protection and conservation agencies are involved in either developing or finalising guidelines to control the beneficial use of biosolids products. Metals bioleaching is a process achieved through bio-acidification. Bio-acidification of biosolids prior to land application can be used to dissolve and remove a significant fraction of the heavy metals content of the product. However, the process also reduces the nutrients content of the resource. Bio-acidification of Loganholme (Queensland) BNR biosoltds dissolved 76% of the total phosphorus and 38% of the TKN. The heavy metals solubilisation results reached 50% for Cr, 79% for Ni, 45% for Zn, 24% for Cu, 30% for Cd, and 82% for Ph.
Article
In the Earth's lithosphere, fungi are of fundamental importance as decomposer organisms, animal and plant pathogens and symbionts (e.g. lichens and mycorrhizas), being ubiquitous in sub-aerial and subsoil environments. The ability of fungi to interact with minerals, metals, metalloids and organic compounds through biomechanical and biochemical processes, makes them ideally suited as biological weathering agents of rock and building stone. They also play a fundamental role in biogeochemical cycling of nutrients, (e.g. C, N, P and S) and metals (e.g. Na, Mg, Ca, Mn, Fe, Cu, Zn, Co and Ni) essential for the growth of living organisms in the biosphere. In addition they play an integral role in the mobilization and immobilization of non-essential metals (e.g. Cs, Al, Cd, Hg and Pb). Most studies on mineral-microbe interactions and microbial involvement in geological processes have concentrated on bacteria and archaea (Prokaryota): fungi (Eukaryota) have, to a certain extent, been neglected. This article addresses the role of fungi in geomicrobiological processes, emphasizing their deteriorative potential on rock, building stone and mineral surfaces and involvement in the formation of secondary mycogenic minerals. Such roles of fungi are also of importance for the global carbon reservoir and have potential biotechnological applications, e.g. in the bioremediation of xenobiotic-, metal- and/or radionuclide-contaminated soils and wastes, and metal/radionuclide recovery.
Article
Bioleaching is a technology applicable to metal extraction from low-grade ores, ore beneficiation, coal beneficiation, metal detoxification, and recovery of metals from waste materials. The technology is environmentally sound and it may lower operational cost and energy requirement. Whereas leaching of sulfidic minerals using chemolithoautotrophic bacteria is the most studied and commercially exploitable aspect of mineral biotechnology today, there is a dearth of literature on the dissolution of nonsulfidic minerals. Biohydrometallurgy of nonsulfidic minerals involves the action of heterotrophic microorganisms. Heterotrophic bacteria and fungi have the potential for producing acidic metabolites that are able to solubilize oxide, silicate, carbonate and hydroxide minerals by reduction, acidolysis and complexation mechanisms. It is an important aspect of biohydrometallugy that requires development to meet future needs.
Article
A study was initiated to analyse metal flows from alum shale to the environment in an area in Öland, Sweden. The study was performed by elemental analysis and leaching experiments of alum shale together with analysis of groundwater and surface water samples.The metal concentrations in non-weathered alum shale were much higher than in weathered or burnt shale, especially for cadmium (Cd), nickel (Ni) and zinc (Zn), indicating a loss of metals during weathering or burning of the shale. The release of metals through weathering was clearly demonstrated by the leaching tests. A 36-week leaching period of non-weathered shale resulted in a drastic drop in pH and a significant increase in metal concentrations in the leachate. The metal concentrations in groundwater were inversely related to the pH. For surface waters, the concentrations of Cd, copper (Cu), Ni and Zn were generally increased compared to background values.In conclusion, metals are released through weathering or burning of alum shale, as well as from heaps of weathered or burnt shale. The release of metals is strongly related to low pH, especially for Cd, Ni and Zn.
Article
The feasibility to recover the gold present in alluvial material, by means of a chlorination process, using chlorine as a reactive agent, has been studied. The influence of temperature and reaction time was studied through changes in the reactant solid. The techniques used to characterize the mineral samples and the reaction residues were stereomicroscopy, X-ray diffraction, X-ray fluorescence and scanning electronic microscopy. Results indicate that gold extraction is favored by increasing, both, the temperature and the reaction time. The best recovery values were of 98.23% at 873K and 3600s and of 98.73% at 873K and 5400s, with very low attack of the matrix containing the metal. The powder of pure gold was not chlorinated at this temperature level.
Article
Immediate environmental conditions expose the fungi organisms to a multitude of stresses in an in situ bio-leaching process. The most significant abiotic stress is from heavy metals which are dissolved by the metabolic products of the organism. Heavy metal stress can stimulate changes in the fungi metabolism which could inactivate its cellular functions critical in maintaining bio-acid production and leaching of minerals. Gradual acclimatization of the organism to increasing concentration of single metals forms the main method of adapting strains for this process. However in a bioleaching process, several metals are dissolved which exposes the organism to various levels of cation toxicity. In this study Aspergillus foetidus was trained using multi metal (Al, Co, Cr, Cu, Fe, Mg, Mn, Ni and Zn) environment to mimic a leaching system. The effect of the metal stress on the fungi metabolism was examined. Bioleaching of weathered saprolite ore using the heavy metal tolerant organism was assessed.