ArticleLiterature Review

Current scenario of chalcopyrite bioleaching: A review on the recent advances to its heap-leach technology

Authors:
  • Gujarat Biotechnology University
  • SDU/Beijing University of Chemical Technology/Satbayev University/Nazarbayev University
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Abstract

Chalcopyrite is the primary copper mineral used for production of copper metal. Today, as a result of rapid industrialization, there has been enormous demand to profitably process the low grade chalcopyrite and "dirty" concentrates through bioleaching. In the current scenario, heap bioleaching is the most advanced and preferred eco-friendly technology for processing of low grade, uneconomic/difficult-to-enrich ores for copper extraction. This paper reviews the current status of chalcopyrite bioleaching. Advanced information with the attempts made for understanding the diversity of bioleaching microorganisms; role of OMICs based research for future applications to industrial sectors and chemical/microbial aspects of chalcopyrite bioleaching is discussed. Additionally, the current progress made to overcome the problems of passivation as seen in chalcopyrite bioleaching systems have been conversed. Furthermore, advances in the designing of heap bioleaching plant along with microbial and environmental factors of importance have been reviewed with conclusions into the future prospects of chalcopyrite bioleaching. Copyright © 2015 Elsevier Ltd. All rights reserved.

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... Since elevating temperature and pressure require high energy consumption and expensive equipment, biological oxidation, also called biooxidation, came into prominence as a cost-effective, energy-efficient and environmentally friendly alternative to pressure oxidation [2]. Moreover, biooxidation is preferred for processing large volumes of low-grade ore and dirty concentrates as it is profitable and eco-friendly [3]. ...
... Thus, the amount of sulfur oxidation increased. Over time, the ORP of the solution increased to 540 mV indicating high ferric iron concentration which can limit A. ferrooxidans growth [3]. It should be mentioned that the solution colour of the mixed culture was less brown than those of A. ferrooxidans and L. ferrooxidans individually; this indicates a lower amount of jarosite precipitation. ...
... It should be mentioned that elemental sulfur on the ore surface acts as a mass transfer barrier and decreases metal solubilization [23]. Equations (2-4) describe the overall reactions of the thiosulfate pathway [3]. ...
Article
This study developed a sustainable method for gold extraction from low-grade refractory ore by combining acidic biooxidation and thiocyanate (SCN) leaching (BIOX-TC) in one system to avoid neutralization and minimize the complexity of the process. Among leachant candidates, thiocyanate was proposed as a less toxic reagent for gold leaching. Furthermore, thiocyanate requires ferric iron as an oxidant for gold extraction and ferric iron can be provided by the microorganisms during biooxidation. In the first step, acidic biooxidation was done using a mixture of acidophiles including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans resulting in 59.6% sulfur oxidation. A preliminary static incubation of Acidithiobacillus thiooxidans also improved biooxidation efficiency achieving higher sulfur oxidation of 87.8%. Following biooxidation, thiocyanate leaching using 0.2M SCN was performed under three different conditions: (1) in a separate flask with 0.01M ferric iron addition; (2) in-situ leaching, in the biooxidation flask with the mixed bacterial culture); (3) in-situ leaching in the biooxidation flask with the bacterial culture and with 0.01M additional ferric iron. It was found that in-situ thiocyanate leaching of the biooxidized ore in presence of bacterial culture and without ferric iron addition resulted in the highest gold recovery (86.9%). The biooxidation mechanism and its kinetics have been extensively discussed in this paper.
... The pH level is also a key factor for microbial colonization and metabolism. According to [27], the growth of Leptospirillum ferriphilum is inhibited below pH 1.0 and above 3.0, with an optimum pH between 1.3 and 1.8 [30]; Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus are dominant at pH 2.0 and 2.5; and Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans are often detected at pH 2.0 [30]. ...
... The pH level is also a key factor for microbial colonization and metabolism. According to [27], the growth of Leptospirillum ferriphilum is inhibited below pH 1.0 and above 3.0, with an optimum pH between 1.3 and 1.8 [30]; Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus are dominant at pH 2.0 and 2.5; and Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans are often detected at pH 2.0 [30]. ...
... According to [30], archaea growing heterotrophically have played a significant role in bioleaching along with the autotrophs. Mesophiles that utilize organic substrates (but often not Fe(II)) belonging to the genera Acidiphillum, Acidocella, Acidisphaera, and Acidobacterium have been isolated from acidic environments along with chemolithotrophs such as Acidithiobacillus ferrooxidans. ...
Article
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This paper reports on a study of column bioleaching of a low-grade chalcopyrite ore that is currently dump-leached under natural biological conditions without any control over microbial populations. The experimental methodology was focused on the effect of managing the bacterial populations in a raffinate solution sourced from a dump-leach operation. This study presents results from columns of two heights (0.45 and 1.0 m). We demonstrated that intermittent irrigation enhanced the chalcopyrite dissolution during column leaching, but excessively long rest periods negatively affected the chemical and bacterial activity due to the shortage of oxidizing agents and/or nutrients for microorganisms. The recovery of low-grade chalcopyrite ore was enhanced by increasing the microbial cell density. The addition of 1.5 × 108 cells/mL to the 0.45 m column and 5.0 × 107 cells/mL to the 1 m column resulted in increased extraction, with the copper dissolution increasing from 32% to 44% in the 0.45 m column and from 30% to 40% in the 1.0 m column over 70 days of leaching. Under these conditions, the pH level remained constant at ~1.8, and the redox potential was around 840 mV vs. the SHE throughout the experiment. These results provided useful insights for evaluating a sustainable controlled dump-based technology for mineral bioprocessing
... Chalcopyrite, the most abundant copper-containing mineral in the Earth's crust, constitutes 70% of these minerals [3]. However, the bioleaching efficiency of chalcopyrite is currently insufficient for industrial-scale application [35][36][37]. ...
... Important process parameters must be fully considered, including the choice between single-layer or multi-layer heap modes, agglomeration techniques, crushing size, and irrigation rates, all of which have implications for industrial operations [35]. Acid consumption, neutralization, and expected recovery should also be carefully evaluated for the economic viability of heap leaching. ...
Article
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Heap bioleaching is considered to be a less energy-intensive metal-extraction technique compared to other methods, making it particularly attractive for low-grade sulfide ores. It has been successfully applied to recovery of copper, gold, and uranium from ores over decades. Despite its seemingly straightforward nature, heap bioleaching can experience failures if the ore is unsuitable or the heap leach process is not thoroughly investigated and well-developed. Therefore, multidisciplinary approaches are essential for research and development in heap bioleaching, as its performance depends on numerous processes operating across a wide range of length scales. This review focused on the current state of knowledge regarding the understanding of multi-scale mechanisms in heap bioleaching and the use of multidisciplinary approaches at different scales to develop the process. The investigation covered various scales, such as atomic and molecular, mineralogy and microbes, reaction particles, heap bioleaching units and full-scale factory production. Different approaches were employed to gain a comprehensive understanding of the microbial molecular structure and metabolism, the structure and reaction of minerals, microbial–mineral interaction, particles and aggregation states, and multiphase flow transfer, as well as laboratory experiments, modeling, industrialization, and operation optimization. We emphasized the need for collaboration among researchers from different disciplines and stress the importance of considering the coupling effects of physical, chemical, and microbiological factors when running heap bioleaching plants. Such collaboration and coupling are vital for successful implementation and optimization of heap bioleaching processes. This paper aimed to provide a comprehensive overview of current research related to heap bioleaching at different scales and disciplines, and gave implications to heap bioleaching technology development.
... Traditional pyrometallurgical technology is a method to effectively process sulfide ores, but it is restricted by the high consumption of resources and the serious pollution of the ecological environment. Bioleaching, as a environmentally friendly method, offers a superior alternative for treating low-grade sulfide ores [2]. This method is highly efficient and costeffective in extracting metals from sulfide ores, particularly for certain types of ores like low-grade ores, tailings, and waste ores that traditional techniques fail to process economically and efficiently. ...
... After 60 days, the A1 peak in the control group demonstrated a significant negative shift compared to the experimental group. This suggested that the chalcopyrite in the control group was more readily converted to Cu2S or intermediate non-stoichiometric chalcopyrite, according to Equations (1) and (2). The enhancement of current density indicated that the products exhibited good electrochemical activity, which facilitated charge transfer and rendered the reaction more facile [51]. ...
Article
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Low-temperature bioleaching is relevant to the recovery of metals in alpine mines, but its development has been constrained by low bioleaching rates at high pulp concentrations. To this end, the bioleaching effect of the microbial community after the domestication of pulp concentration at 6 °C was studied. Domestication improved the bioleaching rate of copper. Environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD), and electrochemical measurements revealed that the domestication process aggravated the corrosion of the chalcopyrite surface by accelerating its dissolution reaction. High-throughput sequencing technology indicated that Acidithiobacillus spp., Leptospirillum spp., and Acidiphilium spp. were the major lineages of the domesticated microbial community. The analysis of the microbial community revealed that domestication changed the microbial structure, enhancing the adaptability of the microbial community to pulp concentrations and acidic conditions. This study uncovered the mechanism by which domestication enhanced the bioleaching efficiency of the microbial community at low temperatures.
... A branch of hydrometallurgy and biotechnology known as "biohydrometallurgy" uses microorganisms to extract metals and valuable products from minerals and secondary sources. Resource conservation, pollution avoidance, and environmental remediation are among the environmental issues that biohydrometallurgical technology is being developed to address at the moment [124,125]. Examples include the separation of radionuclides and metal values from heavy nuclear waste and other waste sources [126], the elimination of dispersed oil from oily wastewater, the recycling of plastics, the recycling of waste paper to create clean cellulose products, and the production of clean coal, which all serve to highlight the value and necessity of developing improved biohydrometallurgical technology [127,128]. The usage of this method is likely most notable in the bauxite residual mineral business, where over 800,000 tons of bauxite minerals are treated by the Bayer process. ...
... Biohydrometallurgy and bioleaching are based on microbiological processes that result in the eventual recovery of metals. In actuality, abiotic physical and chemical processes are often used to process metal-bearing minerals, whereas biohydrometallurgy makes use of the fact that microorganisms are influencing mineral transformations [49,125]. Chemical transformations and transport processes may be amplified by interactions between microorganisms and minerals [130]. ...
Article
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Aluminum is produced from its primary bauxite ore through the Bayer process. Although Al is important nowadays in the development of humanity, its production leads to the generation of a huge amount of waste, called red mud. Globally, the estimation of the stock of red mud is about 4 billion tons, with about 10 million tons located in Turkey. The presence of rare-earth elements (REEs) in crucial materials such as red mud makes it a major source of these elements. A number of methods have been developed for treating red mud, which are employed globally to recover valuable products. The application of a suitable method for REE extraction from red mud is a way to overcome the supply risk, contributing to reducing the environmental issues linked to red mud pollution. The current review summarizes the research on red mud processing and examines the viability of recovering REEs from red mud sustainably, utilizing hydrometallurgy and biohydro-metallurgy.
... Bioleaching (or Biomining) is a natural process of interaction between microbes and minerals to leach valuable metals from sulfide ores, ore concentrates and mining wastes using acidophilic iron-and sulfuroxidizing bacteria and archaea. The bioleaching process is environmentfriendly, cost-effective and technically feasible process to extract Cu, Ni, Co, Zn, U and to liberate Au particles from goldcontaining arsenopyrite or pyrite ores/ concentrates on industrial scale using heap, dump, in-situ and stirred tank bioreactors leaching processes (Bhatti and Tuovinen 2023; Ristovic et al., 2022;Kaksonen et al., 2020;Watling 2016;Panda et al., 2015;Needham 1974). During bioleaching of copper from ores, sulfuric acid acts as a leaching agent (lixiviant), while ferric sulfate (Fe2(SO4)3) as an oxidant to dissolve copper from chalcopyrite containing ores. ...
... In addition, this process is also being applied for the pretreatment of goldcontaining pyrite/ arsenopyrite ores to liberate Au particles from the sulfide ore matrix. About 30-35% Cu of the total world Cu production is being produced by bioleaching process (Pakostova and Herath 2023). Chile had the first commercial operation in the world exclusively via bioleaching copper sulfide ores (Gentina and Acevedo 2016). ...
... Bio-assisted leaching, or bioleaching, which involves the assistance of microorganisms, has emerged as a promising alternative for the leaching of sulfide minerals/ores (Chaerun et al., 2023;Vera et al., 2022;Watling, 2006). This approach is particularly focused on treating low-grade sulfide minerals/ores (Mubarok et al., 2017;Panda et al., 2015). ...
... Chalcopyrite (CuFeS 2 ) is the world's most abundant primary sulfide, and it needs to be exploited in major amounts in the future for copper bioleaching. Copper recovery from chalcopyrite through biohydrometallurgical processes has been challenging due to mineral surface passivation, leading to very low copper recovery at mesophilic temperatures (<40% in comparison to fresh chalcopyrite) [4,5]. The formation of passivation layers (elemental sulfur and jarosites) may be due to the temperature range, the presence of microorganisms, a high concentration ratio of Fe(III) to Fe(II), and the Cu(II) concentration, varying the passivation redox potential (ORP) from 475 to 635 mV (vs. ...
Article
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Bioleaching, a process catalyzed by acidophilic microorganisms, offers a sustainable approach to metal extraction from sulfide minerals. Chalcopyrite, the world’s most abundant copper sulfide, presents challenges due to surface passivation limiting its bioleaching efficiency. Also, indigenous species and microbial communities may present high copper extraction rates and offer new possibilities for application in bioleaching processes. This study examines the bioleaching potential of microbial isolates and communities obtained from Amolanas Mine in Chile. Samples were collected, cultivated, and identified by Sanger sequencing. The bioleaching potential and biofilm formation of isolates and enrichments were evaluated on pyrite and chalcopyrite. The results show the isolation of nine Leptospirillum and two Acidithiobacillus strains. The bioleaching experiments demonstrated good copper bioleaching potentials of the Leptospirillum I2CS27 strain and EICA consortium (composed mainly of Leptospirillum ferriphilum, Acidiphilium sp., and Sulfobacillus thermosulfidooxidans), with 11% and 25% copper recovery rates, respectively. Microbial attachment to the surface mineral was not mandatory for increasing the bioleaching rates. Our findings underscore the importance of indigenous microbial communities in enhancing copper bioleaching efficiency.
... hematite, or siderite, which are considered impurities and indeed compromise the qualities and properties of the sand itself (Platias et al. 2014). This has fostered the development of technologies to reduce or eliminate the presence of ferrous compounds in the raw material (Zhang et al. 2012;Du et al. 2011;Panda et al. 2015a). With the aim to improve the technological properties of materials, physical (electromagnetic and gravitational separation) and chemical (leaching with inorganic and organic acids and reductants) methods of mineral processing have been applied. ...
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In many European regions, both local metallic and non-metallic raw materials are poorly exploited due to their low quality and the lack of technologies to increase their economic value. In this context, the development of low cost and eco-friendly approaches, such as bioleaching of metal impurities, is crucial. The acidophilic strain Acidiphilium sp. SJH reduces Fe(III) to Fe(II) by coupling the oxidation of an organic substrate to the reduction of Fe(III) and can therefore be applied in the bioleaching of iron impurities from non-metallic raw materials. In this work, the physiology of Acidiphilium sp. SJH and the reduction of iron impurities from quartz sand and its derivatives have been studied during growth on media supplemented with various carbon sources and under different oxygenation conditions, highlighting that cell physiology and iron reduction are tightly coupled. Although the organism is known to be aerobic, maximum bioleaching performance was obtained by cultures cultivated until the exponential phase of growth under oxygen limitation. Among carbon sources, glucose has been shown to support faster biomass growth, while galactose allowed highest bioleaching. Moreover, Acidiphilium sp. SJH cells can synthesise and accumulate Poly-β-hydroxybutyrate (PHB) during the process, a polymer with relevant application in biotechnology. In summary, this work gives an insight into the physiology of Acidiphilium sp. SJH, able to use different carbon sources and to synthesise a technologically relevant polymer (PHB), while removing metals from sand without the need to introduce modifications in the process set up. Supplementary Information The online version contains supplementary material available at 10.1007/s00203-024-04005-4.
... Adequate aeration is supplied to the pile, this gas flow is injected under the bed of the ore, giving O 2 and CO 2 to the process(Kaksonen et al. 2018). (5) Acidophilic bacteria populate the mineral surfaces with their exopolysaccharide (EPS), while there is a totally indirect interaction between the oxidizing reagents and the minerals, achieving in both ways the leaching of the mineral(Panda et al. 2015). ...
Article
Biotechnology has increasing relevance worldwide in the mining sector, either as a response to the recovery of metals (gold, silver, copper, zinc, nickel, among others) as well as an alternative in the bioremediation of contaminated soil and water, frequent problems directly linked to mining activities. Hence, acidophilic microorganisms are of special scientific and industrial interest for the sustainable use of mineral resources. Nowadays, a wide variety of acidophilic chemolithotrophic microorganisms (MOs) are recognized, Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Acidithiobacillus caldus, and Leptospirillum ferrooxidans, among others; those MOs grow in culture medium at pH ≤ 3 and obtain cellular energy from the oxidation of inorganic compounds, such as sulfur and iron. These microorganisms have different abilities to act on the mineral, converting insoluble metal sulfides into soluble metal sulfates of those species that are of interest, or that prevent optimal recovery of a specific mineral. Such microorganisms have been applied in biomining operations and are internationally known for the recovery of valuable metals from low-grade ores and refractory ores. Likewise, these acidophilic MOs can bioremediate soils contaminated with metals, extract metals from sludge generated as a byproduct in wastewater treatment, detoxify hazardous waste and recover metals from electronic waste; so the main interest of biomining processes lies in the economic impact that has benefited the world, since it is known that 5% of the gold and 20% of the copper that has been extracted worldwide are using this type of bacteria in bioleaching processes. The objective of this review is to expand the knowledge of the characteristics and applications of the main acidophilic microorganisms used in the solubilization/extraction of minerals, whether for the recovery of metals, bioremediation, or reduction of metals in different systems.
... 19 The main role of iron-oxidizing microorganisms is to regenerate the essential Fe 3+ ion, which provides an oxidative attack on the material and leads to the bio-dissolution of metals. 39 Because e-wastes such as LIBs are noncarbon-based materials and contain low amounts of sulfur and iron, 40 a proper nutrient medium consisting of Fe 2+ , S 0 and other vital nutrients is important for the proper growth and metabolism of the microorganisms during LIB bioleaching. However, it also is important to determine the optimum ferrous iron concentration in the medium, as higher Fe 2+ concentrations reduce bioleaching efficiency owing to the toxic effects of iron. ...
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BACKGROUND A bioleaching process could offer the advantage of higher metal recovery in a sustainable manner even from lithium‐ion battery (LIB) samples with very low metal concentrations. In recent years, there has been a significant increase in the use of secondary resources such as LIBs for various purposes including transportation, large‐scale energy storage and use in portable devices. RESULTS The adaptation of a mixed culture of acidophilic microorganism (lab stock culture) to a representative LIB sample allowed the setting of 0.5% of the pulp density under lab scale conditions. The maximum metal dissolution by bioleaching in a 1‐L bioreactor for the as‐received and thermally treated samples was found to be Li (67% & 49%), cobalt (81% & 86%), nickel (99% & 87%) and manganese (86% & 75%). Likewise, on the 10‐L scale, the dissolutions observed were: Li (80% & 67%), Co (75%), Ni (91% & 88%) and Mn (63% & 75%) for the as‐received and heat‐treated samples, respectively. CONCLUSION Parameters such as particle size, leaching time, pH and iron ions (Fe²⁺) affect the efficiency of acidophilic bioleaching of Li, Co, Ni and Mn from spent LiBs. © 2024 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).
... The bioleaching process is currently carried out in the industry through technologies such as Heap leaching or Dump leaching, and in Continuous Stirred Tank Reactors (cSTRs) (Rawlings et al., 2003). Although it stands out mainly as a pre-treatment of Au ores (Rawlings et al., 2003), bioleaching has been successfully applied to obtain copper, nickel and cobalt (Panda et al., 2015;Petersen, 2010). ...
... Additionally, the iron content in chalcopyrite can lead to the formation of passivating layers on the mineral surface, further impeding the leaching process. To address this issue, a range of ways is used, including high-temperature pressure leaching [9][10][11], bioleaching [12][13][14][15], chemical pretreatment [16,17], and a combination of leaching methods [18][19][20]. The use of sulfate, nitrate, chloride, and other leaching agents has been investigated. ...
Article
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In this study, SDS is used to enhance the sulfuric acid leaching of chalcopyrite in aqueous and isopropanol media. The presence of SDS increased copper extraction into the solution in both solvents. However, it was the “isopropanol–sulfuric acid–SDS” system that proved to be particularly effective for copper recovery from chalcopyrite. The positive effect of SDS can be attributed to the reduction in the solution’s surface tension and the enhancement of mineral wetting. Additionally, the presence of SDS as a surfactant induces changes in the adsorption patterns of formed sulfur species on the mineral surface. SDS competes with sulfur for occupancy on the surface binding sites. This competitive interaction has the potential to diminish the formation of a substantial sulfur layer on the mineral surface. Under optimal conditions (isopropanol media, 2 M H2SO4, 65 °C, 120 min, 0.6 g/L SDS), copper recovery into the solution was 83%, and this is a considerable achievement for chalcopyrite leaching at ambient pressure in the absence of strong oxidizers.
... These methods are well known for generating large amounts of hazardous waste at the end [8,9]. Use of advanced alternative technologies that will be less energy-intensive, low cost and environmentally friendly copper extraction technologies are needed especially in resource-limited countries like Zambia [10,11]. It is important because high-grade and oxide ores are depleting rapidly [12] while the demand for copper in the world market is high. ...
... Biofilm formation is of value in bioleaching-based technology. Of the three proven mechanisms for bioleaching of sulfide minerals, contact, non-contact and cooperative models Natarajan, 2018;Panda et al., 2015), two mechanisms (contact and cooperative) require biofilm formation. Fathollahzadeh, Becker, et al. (2018) conceptualized the bioleaching of phosphate minerals in the same three mechanisms and showed that the leaching efficiencies in the absence of contact to minerals were significantly lower than in contact with minerals, which signifies the importance of microbial contact in comparison to non-contact leaching (Fathollahzadeh et al., 2019;Fathollahzadeh, Becker, et al., 2018). ...
Article
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Microbial attachment and biofilm formation is a ubiquitous behaviour of microorganisms and is the most crucial prerequisite of contact bioleaching. Monazite and xenotime are two commercially exploitable minerals containing rare earth elements (REEs). Bioleaching using phosphate solubilizing microorganisms is a green biotechnological approach for the extraction of REEs. In this study, microbial attachment and biofilm formation of Klebsiella aerogenes ATCC 13048 on the surface of these minerals were investigated using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In a batch culture system, K. aerogenes was able to attach and form biofilms on the surface of three phosphate minerals. The microscopy records showed three distinctive stages of biofilm development for K. aerogenes commencing with initial attachment to the surface occurring in the first minutes of microbial inoculation. This was followed by colonization of the surface and formation of a mature biofilm as the second distinguishable stage, with progression to dispersion as the final stage. The biofilm had a thin‐layer structure. The colonization and biofilm formation were localized toward physical surface imperfections such as cracks, pits, grooves and dents. In comparison to monazite and xenotime crystals, a higher proportion of the surface of the high‐grade monazite ore was covered by biofilm which could be due to its higher surface roughness. No selective attachment or colonization toward specific mineralogy or chemical composition of the minerals was detected. Finally, in contrast to abiotic leaching of control samples, microbial activity resulted in extensive microbial erosion on the high‐grade monazite ore.
... Its industrial application is known as bioleaching, which is mostly suited to treat low-grade sulfide ores. This cost-effective process exhibits a high copper recovery from secondary sulfides (Deveci and Ball 2010;Fu et al. 2016;Olubambi, Potgieter, and Borode 2008;Panda et al. 2015;Watling 2006). In this context, Akcil, Ciftci, and Deveci (2007) carried out a study to compare the bioleaching of a chalcopyrite ore assaying 15.75% Cu, by the mesophile microorganisms Acidithibacillus ferrooxidans, Leptospirillum ferrooxidans and Acidithiobacillus thiooxidans at 30ºC. ...
Article
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Chalcopyrite ores are processed mostly by pyrometallurgical techniques due to the refractory nature of the mineral to the current hydrometallurgical techniques. In order to overcome such refractoriness, pretreatment steps such as sulfurization may be applied to produce different copper phases and therefore improve the metal dissolution in the leaching step. The current study investigated the reaction products of the reaction between chalcopyrite and elemental sulfur at different chalcopyrite/sulfur ratios (1/1 and 1/2), reaction time (60 min and 90 min), and temperature (350ºC, 400°C and 450ºC). The sulfurization experiments revealed that covellite, nukundamite, bornite, and pyrite-like compounds were produced according to the experimental conditions applied. Then, the sulfurization products were submitted to chemical leaching tests at temperatures ranging from 32ºC to 70ºC, whereas bioleaching tests were also carried out with Acidithiobacillus ferrooxidans, at 32ºC. In the chemical leaching experiments at 70ºC, only 14% copper was recovered from the original chalcopyrite sample while the maximum copper extraction was 78% from bornite produced at 450ºC (90 min and mass ratio of chalcopyrite/sulfur of 1/2). On the other hand, copper extraction achieved 96% from the same sulfurization product containing synthetic bornite within 20 days of bioleaching. Bioleaching of the original chalcopyrite sample implied in a copper recovery of only 25% in the same period. Summarizing, the current work showed that chalcopyrite sulfurization at 450ºC was able to transform chalcopyrite into a bornite-like phase, which was chemically leached and bioleached by At. ferrooxidans.
... Therefore, chalcopyrite is considered as the alternate Fenton catalyst that rapidly releases Fe 2+ , Cu 2+ , and protons in the system (Eq. 4-8) [103,104]. The iron leaching was found to be much lesser in case of chalcopyrite,while the Cu leaching by chalcopyrite imposes higher toxicity than that of pyrite [105]. ...
Article
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Removal of recalcitrant organic pollutants via advance oxidation process (AOP) is an effective and green approach in the field of wastewater treatment. Fenton process is one such kind of AOP technique that employs iron (Fe) materials and oxidizing agent to attain degradation of organic pollutants though the generation of reactive organic species (ROS). In this review, the utility of natural and synthetic iron materialstowards water remediation process has been discussed in detail in relation to Fenton chemistry. The geochemistry of natural iron materials (oxides and sulfides) and chemistry of synthetic iron materials (nanomaterials and their impregnated forms) has been discussed to understand their role in Fenton processes. Additionally, the emergence of ferrates as a new and promising candidate for the removal of organic pollutants has been highlighted. A detailed investigation on the effect of various operational parameters such as pH, catalyst dose, foreign ion, oxidant concentration, and chelating agents in affecting the performance of iron materials has been highlighted. A summary on the potency of various iron materialstowards removing diverse kind of organic compounds from aqueous medium has been provided. At last, the review has been concluded with emphasizing the drawbacks and benefits of using Fe material for realizing Fenton and Fenton-like processes.
... Biofilmforming bacteria differ from planktonic bacteria in that they are highly resistant to antibiotics, harsh environments, and host immune defenses Narenkumar et al. 2021). Biofilm-forming bacteria possess distinctive characteristics in terms of physiology, metabolism, degradation, and utilization (Miller et al. 1992, Panda et al. 2015 of substrates. Sabrina et al. discovered that biofilmforming bacteria, such as Halobacterium salinarum, were more resistant to metal ions such as Cu 2+ and Ni 2+ than planktonic bacteria (Volkel et al. 2018). ...
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As the demand for metal resources increases and the quality and availability of rich ore resources decline, the focus is shifting to low-cost, eco-friendly bioleaching technologies that can effectively utilize low-grade minerals. The stress on bioleaching microorganisms due to high concentrations of metal ions in the bioleaching system is one of the most important factors limiting the effectiveness of bioleaching. Using the common copper-bearing ore bioleaching process as an example, the copper ion concentration reached 6 g/L. An in-depth examination of the copper defensive mechanism of bioleaching microorganisms will help elucidate the physiological mechanism of such extremophiles and pave the way for future genetically engineered highly efficient strains. We elaborate on the copper tolerance mechanism of extremophiles through the lens of biofilms, cell membranes, metal transport mechanisms, intracellular buffer mechanisms, and energy metabolism.
... These species oxidize ferrous iron to ferric iron and/or reduced sulfur compounds to sulfuric acid, which leach metals from minerals and wastes via redoxolysis and acidolysis, respectively [5]. Bioleaching also is the metal-extracting practice from sulfides and/or iron-containing ores by microorganisms [6]. Shewanella oneidensis is a bacterium notable for its ability to reduce metal ions and lives in environments with or without oxygen. ...
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Conventional method for gold extraction using cyanide is not environmentally friendly and harmful to the environment. Thus, we investigate the potential of Shewanella oneidensis as bioleaching agent for gold extraction to replace the cyanide leaching process. The concentration of Fe (II) was determined via Ferrozine Assay method using Spectrophotometer, while the concentration of gold (Au) was determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Some minerals such as pyrite, arsenopyrite, hematite, magnetite, and quartz were detected in the ore samples using XRD. The results show, S. oneidensis MR-1 was able to reduce Fe (III) to Fe (II) that can increase gold concentration. Gold concentrations were increased from 19 ppb to 28.5 ppb with 50% of percentage yield increased. In addition, the result shows hematite and magnetite in the samples was also reduced after bioleaching which might lead to the increasing amount of gold concentration. As a conclusion, S. oneidensis MR-1 was shown to be effective for bioleaching to improve gold extraction process.
... Meanwhile, a previous study has also found a high relative abundance of Sulfurifustis near the smelting area (Liu et al. 2022b). Thiobacillus is iron-oxidizing, sulfur-oxidizing, and acidophilic bacterial strain, which is frequently found in acidic soil of mining areas, bioleaching process, and acid mine wastewater (Panda et al. 2015). Thiobacillus can extract HMs from sewage sludge and bioleach HMs (Leduc et al. 1997) from contaminated soil by direct biooxidation or indirect chemical oxidation of HMs via Fe 3+ produced in the bioleaching process (Zhang et al. 2009). ...
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... intensive, low cost and environmentally friendly copper extraction technologies (Panda et al., 2015). It is important because high-grade and oxide ores are depleting rapidly while the demand for copper in the world market is higher. ...
... middle residues in columns B and C (Figs. 6f and 6i). These short rod-like cells had the same morphology as the leaching bacteria found by Panda et al. [45], and the porous surface was similar to the model proposed by Ghahremaninezhad et al. [18] for chalcopyrite dissolution catalyzed by Ag + . Compared to the column A, the surface of residues in columns B and C were covered by less deposits and attached by more cells. ...
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... Bio-hydrometallurgical technologies have been widely utilized in the copper industry [81,82], especially for the processing of chalcopyrite, which is well-known for being refractory to conventional leaching methods [83]. Gold has been mainly produced using hydrometallurgical methods based on cyanide leaching [29]. ...
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This white paper covers the fundamentals of hydrometallurgical process synthesis, design, and economic evaluation. Metallurgical and Materials Engineering students and engineers with limited process design experience find it particularly useful. It features theory on process synthesis and analysis, material on hydrometallurgical process simulation, and presents a thorough methodology for estimation of capital and operating costs. It also includes the following five detailed process examples modeled and analyzed with SuperPro Designer: 1) Extraction of Lithium from Spodumene Ore, 2) Bio-Hydrometallurgical Recovery of Copper and Gold, 3) Recycling of Solar Photovoltaic Panels, 4) Hydrometallurgical Recycling of Lithium-Ion Batteries and 5) Manufacturing of NMC 811 Cathode Material for Lithium-Ion Batteries. For additional hydrometallurgical examples of SuperPro Designer, please visit https://www.intelligen.com/industries/metallurgy/
... Solar radiation, wind, and extreme temperatures will all have a great impact on the leaching effect. Some researchers have found that climatic conditions have an important influence on the dissolution process of chalcopyrite [83], especially for insoluble low-grade chalcopyrite, usually the leaching time can be as long as several months or even half a year. During this period, rainfall and nighttime temperature will affect the activity and growth rate of bacteria in the pile, and slow the dissolution of chalcopyrite, which intensifies the formation of a passivation layer on the mineral surface and reduces the leaching efficiency. ...
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The microbial leaching of metal sulfides is now an established biotechnological technology. Over the past 25 years, refinements in the engineering design of bioleaching processes have paralleled advances in our understanding of the diversity and role of the micro-organisms driving the process and the mechanisms by which micro-organisms enhance metal sulfide oxidation. Commercial success started with the treatment of refractory gold concentrates using mesophilic micro-organisms, followed by the development of tank bioleaching processes for the treatment of base metal concentrates. This was, initially, a mesophilic process with limited potential for recovery of copper from chalcopyrite concentrates due to slow rates and low copper extractions. The exploitation of thermophiles represents a major breakthrough in the development of bioleaching technology for the treatment of chalcopyrite-containing ores and concentrates. This development also opened the route to heap bioleaching of chalcopyrite ores, which is now a major focus of research programmes and piloting campaigns. This paper reviews the historical development of minerals bioleaching processes and gives an update on the current status of commercial tank and heap bioleach operations around the world.
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Modern commercial application of biohydrometallurgy for processing ores became reality in the 1950s with the advent of copper bioleaching at the Kennecott Copper Bingham Mine. Early application entailed dump leaching of low-grade, low-value, run-of-mine material. Dump bioleaching has evolved into a commercially accepted option for bioheap copper leaching of higher-grade, higher value ores. This commercial practice is exemplified by at least 11 mining operations. Paradoxically, application of biohydrometallurgy in the pretreatment of refractory gold ores began with processing high value concentrates, using biooxidation-tank processes and was followed by extension to processing low-grade, lower value ores in heaps. Now, bioleaching has been extended to the commercial extraction and recovery of cobalt. Even with the current success of biohydrometallurgical applications in the mining industry, the real potential of biotechnology in mining remains to be realized. As confidence in commercial bioprocessing grows and experience extends the application's knowledge base, innovations and new commercial practices will emerge. Near-term future commercial applications will likely remain focused on recoveries of copper, gold and possibly nickel. Recent technical advances show that very refractory chalcopyrite can be successfully bioleached. Processes for copper recovery from this mineral will include both heap and stirred-tank reactors. Next generation technologies for pretreatment of refractory gold ores will be based on use of thermophilic bacteria for sulfide oxidation. For biohydrometallurgy to commercially advance, the microbiologist must work cooperatively with the practitioners of the technology for mutual understanding of operational limitations and practical constraints affecting the microbiological component. q 2001 Elsevier Science B.V. All rights reserved.
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This paper studies the effects of quartz on bioleaching of chalcopyrite by Acidithiobacillus ferrooxidans, LD-1 through shaking flask experiments. The results showed that quartz concentration can affect the copper extraction. After 32 days, copper extraction of the leaching system at 50 g L−1 quartz concentration increased by about 20%, compared with that of the leaching system without quartz. XRD analysis showed that the amounts of jarosite on the chalcopyrite surface may reduce by the mechanical friction action between fine particles of quartz and chalcopyrite. The analysis of SEM indicated that the surfaces of chalcopyrite particles were eroded by different degrees and the degrees of change were the same as the effects of quartz concentration on copper extraction.
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Draft genome sequences of Acidthiobacillus thiooxidans and A. caldus have been annotated and compared to the previously annotated genome of A. ferrooxidans. This has allowed the prediction of metabolic and regulatory models for each species and has provided a unique opportunity to undertake comparative genomic studies of this group of related bioleaching bacteria. In this paper, the presence or absence of predicted genes for eleven metabolic processes, electron transfer pathways and other phenotypic characteristics are reported for the three acidithiobacilli: CO2 fixation, the TCA cycle, sulfur oxidation, sulfur reduction, iron oxidation, iron assimilation, quorum sensing via the acyl homoserine lactone mechanism, hydrogen oxidation, flagella formation, Che signaling (chemotaxis) and nitrogen fixation. Predicted transcriptional and metabolic interplay between pathways pinpoints possible coordinated responses to environmental signals such as energy source, oxygen and nutrient limitations. The predicted pathway for nitrogen fixation in A. ferrooxidans will be described as an example of such an integrated response. Several responses appear to be especially characteristic of autotrophic microorganisms and may have direct implications for metabolic processes of critical relevance to the understanding of how these microorganisms survive and proliferate in extreme environments, including industrial bioleaching operations.
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The changes of pH, redox potential, concentrations of soluble iron ions and Cu2+ with the time of bioleaching chalcopyrite concentrates by acidithiobacillus ferrooxidans were investigated under the different conditions of initial total-iron amount as well as mole ratio of Fe(III) to Fe(II) in the solutions containing synthetic extracellular polymeric substances (EPS). When the solution potential is lower than 650 mV (vs SHE), the inhibition of jarosites to bioleaching chalcopyrite is not vital as EPS produced by bacteria can retard the contamination through flocculating jarosites even if concentration of Fe(III) ions is up to 20 g/L but increases with increasing the concentration of Fe(III) ions; jarosites formed by bio-oxidized Fe3+ ions are more easy to adhere to outside surface of EPS space on chalcopyrite; the EPS layer with jarosites acts as a weak diffusion barrier to further rapidly create a high redox potential of more than 650 mV by bio-oxidizing Fe2+ ions inside and outside EPS space into Fe3+ ions, resulting in a rapid deterioration of ion diffusion performance of the EPS layer to inhibit bioleaching chalcopyrite severely and irreversibly.
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The chemical and physical conditions in sulphide heaps provide a complex environment for micro-organisms, with differences in redox potential, acidity, temperature, oxygen and solution chemistry conditions being experienced both temporally and spatially. One of the most important parameters for successful microbial colonisation and active microbial metabolism is suitable pH conditions in the heap. Typically heaps reach tens of metres high and the pH of irrigation solution travelling through heap changes significantly.In this study, we investigated the effect of pH and acid stress for moderately thermophilic and thermophilic mixed cultures, operating at 50–60°C in a heap bioleaching environment. Results collected from laboratory scale column reactors packed with the low grade whole ore and irrigated with different pH solutions during a temperature shift from moderately thermophilic conditions to thermophilic conditions are discussed.
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Recovery of metal value, especially from low-grade ores and overburden minerals using acidophilic bacteria through the process of bioleaching is an environmentally benign and commercially scalable biotechnology. In recent years, while the 'OMICS' landscape has been witnessing extensive application of computational tools to understand and interpret global biological sequence data, a dedicated bioinformatic server for analysis of bacterial information in the context of its bioleaching ability is not available. We have developed an on-line Bacterial Bioleaching Protein Finder (BBProF) System, which rapidly identifies novel proteins involved in a bacterial bioleaching process and also performs phylogenetic analysis of 16S rRNA genes. BBProF uses the features of Asynchronous Java Script and XML (AJAX) to provide an efficient and fast user experience with minimal requirement of network bandwidth. In the input module the server accepts any bacterial or archaeal complete genome sequence in RAW format and provides a list of proteins involved in the microbial leaching process. BBProF web server is integrated with the European Bioinformatics Institute (EBI) web services such as BLAST for homology search and InterProScan for functional characterization of output protein sequences. Studying evolutionary relationship of bacterial strains of interest using Muscle and ClustalW2 phylogeny web services from EBI is another key feature of our server, where 16S rRNA gene sequences are considered as input through a JQUERY interface along with the sequences present in the BBProF database library. Complete genome sequences of 24 bioleaching microorganism characterized by genomic and physiological study in the laboratory and their respective 16S rRNA gene sequences were stored in the database of the BBProF library. To our knowledge BBProF is the first integrated bioinformatic web server that demonstrates its utility in identifying potential bioleaching bacteria. We hope that the server will facilitate on-going comparative genomic studies of bioleaching microorganisms and also assist in identification and design of novel microbial consortia that are optimally efficient bioleaching agents.
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The application of bacterial oxidation as a pretreatment step for the extraction of gold from arsenical gold sulphide concentrates offers potentially significant economic advantages over oxidative pretreatment alternatives. In this study the bacterial oxidation of an extremely refractory gold sulphide concentrate, from Olympias, Greece, is examined.Leaching tests were conducted in air-stirred pachuca reactors in order to determine the effect of pulp density on the degree of pyrite and arsenopyrite oxidation.Cyanidation tests were conducted in order to determine the degree of gold and silver liberation in relation to the degree of each sulphide phase oxidised and to the cyanide consumed.Mathematical analysis of the leaching data allowed the gold distribution in each sulphide mineral phase to be estimated and the gold recoveries according to the degree of each mineral oxidised predicted.
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Bioleaching, also referred to as minerals biooxidation, and bioremediation have been widely employed commercially for heap and dump bioleaching of secondary copper sulfide ores, sulfidic-refractory gold concentrates and treatment of acid rock drainage. Technical and commercial challenges, identified in this paper, remain for bioleaching of primary sulfides and complex ores. New frontiers for the technology exist in processing massive sulfides, silicate-locked minerals and in the more distant future in-situ leaching. Decommissioning of cyanide heap leach operations and stabilizing mine wastes using biotechnology are opportunities requiring intensive and focused research, development and engineering efforts.
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Heap bioleaching of low grade chalcopyrite (CuFeS2) was carried out in 1000 tons scale over a time period of 383 days. Bacterial solution was prepared and re‐circulated in specially designed BACFOX (BACterial Film OXidation) tank. The micro‐organisms used in the pilot scale were a mixed culture of acidophilic bacteria predominantly of the Acidithiobacillus ferrooxidans strain. Effect of rest period, solution recirculation, acid concentration, frequency of solution transfers and seasonal effects on copper recoveryweremonitored. The leaching studies showed a cumulative copper dissolution rate of 0.14% per day (2.37 kg d−1). The overall recovery of the heapwas 30%. Variation in leaching efficiency and some of the precautionary measures to improve performance of heap bioleaching are also discussed.