Electrochemical investigation of microbially and galvanically leached chalcopyrite

Tanne, Christoph; Schippers, Axel

doi:10.1016/j.hydromet.2021.105603

Cited by 30 publications

(13 citation statements)

References 29 publications

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“…Leaching rate decreasing sulfur and/or polysulfide layers were observed on acid-soluble sphalerite in the absence of sulfur oxidizers (Fowler and Crundwell 1998 ). Similar problems are known for chalcopyrite as well (Tanne and Schippers 2021 ). However, at appropriate redox potentials during bioleaching, inhibiting sulfur layers can be avoided.…”

Section: Sulfur Chemistry—implications For Bioleaching Kineticsmentioning

confidence: 57%

See 1 more Smart Citation

Progress in bioleaching: fundamentals and mechanisms of microbial metal sulfide oxidation – part A

Sand

Schippers

Hedrich

et al. 2022

Appl Microbiol Biotechnol

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Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides’ mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution via oxidation of iron(II) ions and inorganic sulfur compounds. Thereby, the metal sulfide attacking agents iron(III) ions and protons are generated. Cells are active either in a planktonic state or attached to the mineral surface, forming biofilms. This review, as an update of the previous one (Vera et al., 2013a), summarizes some recent discoveries relevant to bioleaching microorganisms, contributing to a better understanding of their lifestyle. These comprise phylogeny, chemical pathways, surface science, biochemistry of iron and sulfur metabolism, anaerobic metabolism, cell–cell communication, molecular biology, and biofilm lifestyle. Recent advances from genetic engineering applied to bioleaching microorganisms will allow in the future to better understand important aspects of their physiology, as well as to open new possibilities for synthetic biology applications of leaching microbial consortia. Key points • Leaching of metal sulfides is strongly enhanced by microorganisms • Biofilm formation and extracellular polymer production influences bioleaching • Cell interactions in mixed bioleaching cultures are key for process optimization

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Section: Sulfur Chemistry—implications For Bioleaching Kineticsmentioning

confidence: 57%

“…However, chemically pure metal sulfides are not occurring under natural conditions (except if prepared in the lab). Thus, in practice always, mixed minerals are available, causing the generation of mixed reaction products (Sanhueza et al 1999 ; Dong et al 2022 ) and galvanic coupling (Tanne and Schippers 2021 ).…”

Section: Bioleaching Pathwaysmentioning

confidence: 99%

Progress in bioleaching: fundamentals and mechanisms of microbial metal sulfide oxidation – part A

Sand

Schippers

Hedrich

et al. 2022

Appl Microbiol Biotechnol

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“…This behavior is in agreement with the current understanding of galvanic interactions between metal sulfides. Indeed, as illustrated for instance by the measurements and literature review of Tanne and Schippers, the chalcopyrite rest potential is significantly lower than that of pyrite, and thus, chalcopyrite leaches preferentially than pyrite in the case of electrical contact between the two minerals. However, it has also been recently shown that, if the galvanic coupling can strongly enhance the chalcopyrite leaching rate at high temperature (e.g., at 80 °C in the Galvanox process), this effect is only marginal at moderate (20–30 °C) temperature. , As a consequence, it is very likely that the relatively high content of pyrite (12 wt %) in our concentrate did not induce a significant effect on chalcopyrite dissolution rate in our tests.…”

Section: Resultsmentioning

confidence: 99%

“…However, it has also been recently shown that, if the galvanic coupling can strongly enhance the chalcopyrite leaching rate at high temperature (e.g., at 80 °C in the Galvanox process 48 ), this effect is only marginal at moderate (20−30 °C) temperature. 47,49 As a consequence, it is very likely that the relatively high content of pyrite (12 wt %) in our concentrate did not induce a significant effect on chalcopyrite dissolution rate in our tests.…”

Section: Acs Engineeringmentioning

confidence: 91%

Hydrometallurgical Processing of Chalcopyrite by Attrition-Aided Leaching

Dakkoune

Bourgeois

et al. 2023

ACS Eng. Au

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We report the investigation of a chalcopyrite leaching process that implements millimeter-sized glass beads that are stirred in the leach reactor to combine particle grinding, mechanical activation, and surface removal of reaction products. The paper focuses on demonstrating the impact of the so-called attrition-leaching phenomenon on the leaching rate of a chalcopyrite concentrate and provides a first understanding of the underlying mechanisms. For this purpose, we have compared the copper leaching yield for different configurations under controlled chemical conditions (1 kg of glass beads and 84 g of chalcopyrite concentrate in 2.5 L of H2SO4-H2O solution, pH = 1.3, E h = 700 mV vs SHE, and T = 42 °C). On top of elemental analysis of the leach solution with time, we provide a full characterization of the solid residue based on X-ray diffraction, elemental analysis, and sulfur speciation. We demonstrate that glass beads led to a remarkable enhancement of the leaching rate in conditions where particles were already passivated by simple leaching and even when large amounts of solid products (elemental sulfur and jarosite) were present. An in-depth evaluation of particle size distribution showed that particle breakage occurred during a rather short time (a few hours) at the beginning of the runs, transforming the initial particles with d 4/3 = 30 μm to finer particles with d 4/3 = 15 μm. Then, particle breakage almost stopped, while an attrition phenomenon was evidenced, inducing the formation of very fine particles (<1 μm) and aggregates concomitantly with copper leaching.

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“…Among other factors, it is caused by an increase in the rate of chemical reactions with increasing temperatures [36][37][38]. Moreover, an increase in the solubility of chalcopyrite in ferric sulfate solutions has been repeatedly shown at relatively low values of the redox potential [39][40][41]. Figure 2 indicates that the value of the redox potential was, on average, 100 mV less during bioleaching of the concentrate at 50 • C than at 40 • C. Choosing a more suitable temperature of these two and taking into account that the goal of bioleaching was to achieve the greatest removal of nickel and to obtain a high-grade copper concentrate as solids, a community growing at 40 • C should be selected.…”

Section: Pregnant Leach Solution Characteristicsmentioning

confidence: 99%

Effect of Temperature on Biobeneficiation of Bulk Copper-Nickel Concentrate with Thermoacidophilic Microbial Communities

Panyushkina

Фомченко

Babenko

et al. 2021

Metals

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Bioleaching of the bulk copper–nickel sulfide concentrate was proposed as a method to remove nickel from it and to obtain a concentrate containing copper as chalcopyrite. This approach is based on the different refractoriness of sulfide minerals in ferric sulfate solutions and oxidation by acidophilic microorganisms. The bulk concentrate contained 10.8% copper in the form of chalcopyrite (CuFeS2) and 7.2% nickel that occurred in pentlandite ((Ni,Fe)9S8) and violarite (FeNi2S4). Three microbial communities grown at 35, 40, and 50 °C were used for bioleaching. The microbial community at 40 °C was the most diverse in the genus and species composition. At all temperatures of the process, the key roles in bioleaching belonged to mixotrophic and heterotrophic acidophiles. The highest levels of nickel leaching of 97.2 and 96.3% were observed in the case of communities growing at 40 and 50 °С, respectively. At the same time, the bioleach residue, which could be characterized as a marketable high-grade copper (chalcopyrite) concentrate, was obtained only at 40 °С. This solid contained 15.6% copper and 0.54% nickel. Thus, the biobeneficiation of bulk sulfide concentrates can be a promising field of biohydrometallurgy.

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Electrochemical investigation of microbially and galvanically leached chalcopyrite

Cited by 30 publications

References 29 publications

Progress in bioleaching: fundamentals and mechanisms of microbial metal sulfide oxidation – part A

Progress in bioleaching: fundamentals and mechanisms of microbial metal sulfide oxidation – part A

Hydrometallurgical Processing of Chalcopyrite by Attrition-Aided Leaching

Effect of Temperature on Biobeneficiation of Bulk Copper-Nickel Concentrate with Thermoacidophilic Microbial Communities

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