J. Cent. South Univ. (2020) 27: 1351-1366

DOI: https://doi.org/10.1007/s11771-020-4371-5

Role and maintenance of redox potential on chalcopyrite biohydrometallurgy: An overview

HUANG Xiao-tao(黄小涛)^{1, 2}, LIAO Rui(廖蕤)^{1, 2}, YANG Bao-jun(杨宝军)^{1, 2}, YU Shi-chao(于世超)^{1, 2},

WU Bai-qiang(邬柏强)^{1, 2}, HONG Mao-xin(洪茂鑫)^{1, 2}, WANG Jun(王军)^{1, 2}, ZHAO Hong-bo(赵红波)^{1, 2}, GAN Min(甘敏)^{1, 2}, JIAO Fen(焦芬)^{1, 2}, QIN Wen-qing(覃文庆)^{1, 2}, QIU Guan-zhou(邱冠周)^{1, 2}

1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;

2. Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University,Changsha 410083, China

Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract: Chalcopyrite is one of the most important copper minerals; however, the extracted efficiency of chalcopyrite is still not satisfactory in hydrometallurgy owing to its high lattice energy which leads to its low dissolution kinetics. To overcome the difficulties, many advanced technologies have been developed, including the selection of high effectively bacteria, the inhibition of the passivation film adhered onto the minerals surface, and the maintenance of solution redox potential under an optimum range. Up to date, considerable researches on the first two terms have been summarized, while the overview of the last term has been rarely reported. Based on corresponding works in recent years, key trends and roles of solution redox potential in copper hydrometallurgy, including its definition, effect and maintenance, have been introduced in this review.

Key words: chalcopyrite; copper minerals; solution potential; hydrometallurgy process

Cite this article as: HUANG Xiao-tao, LIAO Rui, YANG Bao-jun, YU Shi-chao, WU Bai-qiang, HONG Mao-xin, WANG Jun, ZHAO Hong-bo, GAN Min, JIAO Fen, QIN Wen-qing, QIU Guan-zhou. Role and maintenance of redox potential on chalcopyrite biohydrometallurgy: An overview [J]. Journal of Central South University, 2020, 27(5): 1351-1366. DOI: https://doi.org/10.1007/s11771-020-4371-5.

1 Introduction

Chalcopyrite is one of the most plentiful and widespread copper-bearing minerals, accounting for about 70% of copper resource in the earth [1-7], and its chemical formula is often believed in the valence state of Cu⁺Fe³⁺S₂^2- instead of Cu²⁺Fe²⁺ S₂^2- [8-11]. Hydrometallurgy technologies for mineral processing and waste processing have been widely developed in recent years, because of their low cost, simple operation and eco-friendly industrial structure [12-26]. The copper extraction from chalcopyrite in hydrometallurgy process, however, is still recalcitrant due to its high lattice energy, thus leading to its low dissolution kinetics [27-34]. To overcome the worldwide problem in theory and practice, research in the following aspects of this filed has attracted much attention: 1) mutation breeding and screening of high activity strains; 2) inhibition for passivation film formed onto the minerals surface; 3) maintenance for solution redox potential within an optimum range.

It is necessary to breed and screen high activity microbial strains from strain library or nature. Their major role in bio-hydrometallurgical applications is to regenerate ferric irons from ferrous irons and protons from sulfur species by oxidation [35, 36]. Different bacteria may have influenced the dissolution kinetics of chalcopyrite, because the physicochemical properties (the hydrophobicity, oxidation-dissolution and dissolution-precipitation of surface elements) of chalcopyrite can be changed by these bacteria adsorbed onto the surface. One rough classification sorts these organisms according to their optimum growth temperature: mesophilic (<40°C), moderately thermophilic (40-55°C) and extremely microorganisms (55-80°C) [37-47]. Passivation of chalcopyrite surface through the formation of an oxide layer can be easily found under the mesophilic conditions, thus leading to the low extraction rate for copper [48-59]. The extremely thermophilic microorganisms are first discovered in the 1960s, they can live and work in more extreme conditions, such as low pH, high temperature, and high-soluble metal concentrations. Due to the absence of cell war, however, they are easily deactivated by high shear stress made by high pulp density, thus affecting the copper extractions [60-65]. Compared with the above-mentioned two bacteria, moderately thermophilic strains have a wider application prospect for they can adapt well to the relatively high temperature in bioreactor and heap leaching process. Thus, they have been paid close attention in recent years [50, 66-70]. The considerably corresponding research completed by researchers is summarized in literatures [71-74].

The dissolution rate of chalcopyrite would be decreased or ceased by the formation of passivation layer coated onto its surface. So, a following problem with its processing at ambient temperatures in the ferric sulfate bioleaching solution is the passivation. The nature of the passivation films is still unclear, although there are many researches about chalcopyrite leaching. One hypothesis is that a sulfur layer would be the main passivating species with chalcopyrite leaching in ferric sulfate solution [75]. And the layer will then block the electron transfer at the solid-liquid interface, thus inhibiting the regeneration of ferric irons from ferrous irons [76]. Another hypothesis is that a copper polysulfide product would be the main products causing the passivation of chalcopyrite in bioleaching [77]. The last hypothesis is that an insoluble sulfate product mainly including jarosite would be the main passivating species with chalcopyrite bioleaching [61, 78-85]. Therefore, three hypotheses can be summarized based on the above-mentioned as following: formation of a sulfur (S⁰) layer [79, 86-89], formation of a copper polysulfide (S_n^2-) product [16, 30, 90, 91], and formation of insoluble sulfate (SO₄^2-) product [53, 61, 78-83, 92]. In 2019, ZHAO et al [76] summarized the passivation mechanism of chalcopyrite bioleaching.

Solution redox potential plays a key role in the leaching of chalcopyrite [35, 93-100]. Fe³⁺has been regarded as one of the most important oxidants for chalcopyrite oxidation according to Eq. (1), and then Fe²⁺ can be oxidized to Fe³⁺ by O₂ and/or microorganisms according to Eq. (2). Redox potential is mainly determined by the ratio of Fe³⁺/Fe²⁺ in the ferric sulfate (bio)-leaching solution [101].

CuFeS₂ +4Fe³⁺→Cu²⁺+2S⁰+5Fe²⁺                  (1)

O₂ +4Fe²⁺+4H⁺→4Fe³⁺+2H₂O               (2)

The impact of redox potential on chalcopyrite leaching has been investigated. Preliminary conclusions can be drawn that higher recovery rate can be obtained by controlling the solution potential under an optimum range, even though the specific interaction mechanisms are still controversial [35, 102-111]. Previous work [109] proved a two-step dissolution model that used to explain the above preliminary conclusion, and a mathematic model was put forward to predict the range of optimum redox potential during chalcopyrite bioleaching. The relationship between copper extractions and redox potential under different leaching conditions, such as copper concentration, ferrous/ferric iron concentration and temperature, was revealed by the above model. Hence, the understanding of the role of redox potential and its maintenance would be useful in accelerating of chalcopyrite dissolution. This review is designed to further improve our previous review article that particularly discussed the role of redox potential and its control technology in chalcopyrite leaching.

In this review, key trends and roles of solution redox potential in copper hydrometallurgy, such as its definition, effect and maintenance, have been summarized based on the existing research results. The purpose of this review is to provide a guidance for industrial application and waste processing, and further industrial application still requires far more effort in the future.

2 Definition of redox potential

Redox potential is used to describe an overall reducing or oxidizing capacity in solution [112]. It is the volts of the affinity of a substance for electrons in a redox action compared with the standard hydrogen electrode (usually sets at 0). The electron transfer processes are from the reducing reactant into the oxidizing reactant. Each species has its own intrinsic redox potential, that is, a positive value represents an oxidizing agent that tends to gain electrons, and a negative value indicates a reducing reactant that tends to donate electrons.

The redox potential is determined by measuring the difference between a stable reference electrode and an inserting electrode connected each other with a salt bridge, which is measured in millivolts (mV) [113]. It is commonly measured using a platinum electrode rather than gold and graphite electrode with a saturated calomel electrode as reference for its reliable performance. The rapid characterization of redox reaction and prediction on stability of various compounds can be known by measuring the redox potential in leaching solution. Hence, in order to know the detailed dissolution process of chalcopyrite, it is necessary to reveal the role of redox potential firstly. In our group, the role of redox potential in leaching solution has been investigated [95]. Figure 1 shows that the energy of Cu²⁺/Cu⁺ is much higher than that of conduction band, and filled states of cuprous overlap with the empty states of chalcopyrite. Therefore, chalcopyrite can capture electrons from cuprous and was reduced to chalcocite. The energy of Fe³⁺/Fe²⁺ locates in the band gap and is higher than the Fermi energy of chalcopyrite. Thus, it is difficult for Fe³⁺ to receive electrons from the chalcopyrite surface, which means that Fe³⁺ is difficult to leach chalcopyrite.

3 Role of redox potential in hydrometallurgy of chalcopyrite

Redox potential is mainly determined by the concentration ratio of Fe³⁺ to Fe²⁺ in aqueous solution during chalcopyrite leaching system, which plays an important role in the copper extractive technology [82]. Therefore, this part is carried out to illustrate the effect of redox potential in hydrometallurgy processing.

Figure 1 Schematic illustration for band structure of chalcopyrite [95]

3.1 Thermodynamic calculation

Chalcopyrite can be reduced to chalcocite at a low redox potential, which is easier to dissolve than primary chalcopyrite [106, 108, 114-117]. A mathematic model based on the above was proposed to predict the optimum range of redox potential in chalcopyrite leaching [109]. The main dissolution process of chalcopyrite can be represented by:

CuFeS₂+3Cu²⁺+3Fe²⁺→2Cu₂S+4Fe³⁺(3)

CuFeS₂+3Cu²⁺+4e^－→2Cu₂S+Fe²⁺(4)

Cu₂S+4Fe³⁺→2Cu²⁺+4Fe²⁺+S⁰(5)

2Cu₂S→4Cu²⁺+8e^－+2S⁰(6)

Equations (7)-(10) can be calculated using equation of Gibbs free energy and Nernst equation, respectively:

E_H1=482+47.3lgC(Cu²⁺)-15.77lgC(Fe²⁺)          (7)

E_H2=481+47.3lgC(Cu²⁺)-15.77lgC(Fe²⁺)          (8)

E_L1=362+31.5lgC(Cu²⁺)                      (9)

E_L2=401+29.5lgC(Cu²⁺)                   (10)

where E_H1 is the high critical potential for the reaction of Eq. (3); E_H2 is the relatively low critical potential for the reaction of Eq. (4); E_L1 is the low critical potential for the reaction of Eq. (5) and E_L2 is the critical potential for the reaction of Eq. (6); C(Cu²⁺) and C(Fe²⁺) represent the concentrations of Cu²⁺ ions and Fe²⁺ ions, respectively.

Equations (7) and (8) show the value of E_H is mainly determined by the ratio of copper concentration and ferrous concentration. As long as the solution redox potential is lower than the value of E_H, chalcopyrite can be reduced to chalcocite, then increasing its dissolved rate. Similarly, the copper concentration can determine the value of E_L obtained from Eqs. (9) and (10). Therefore, under the optimum range of redox potential E_L-E_H conditions, the dissolution of chalcopyrite can be accelerated by the formation of chalcocite in both chemical leaching and bioleaching.

3.2 Promoting formation of intermediate products

The optimum range of redox potential is helpful to generate the intermediate products such as bornite or chalcocite onto the surface, thus accelerating the dissolution of chalcopyrite [118].

LIU et al [87] concluded that the above products could be observed in the early state when the redox potential was lower than 500 mV (vs SCE). As time goes, however, these products vanished and the copper extraction was stagnant whilst the redox potential was up to 550 mV (vs SCE). Similarly, the bornite can be observed in a low potential range, and then disappeared in the high range, using the analysis of the leaching residues in the different reaction stages [119]. ZENG et al [120] found that the formation of chalcocite (Cu₂S) would be much easier than that of other intermediate products when the redox potential was about 477 mV (vs Ag/AgCl) and similar conclusion is given by other researchers [121, 122].

Furthermore, a two-step leaching mechanism of chalcopyrite was proposed by HIROYOSHI et al [103, 123]. They held that the first step is the reduction of chalcopyrite to chalcocite at low redox potential. Then the newly generated solid species can be oxidized more easily than CuFeS₂ in the same condition. Also, GU et al [116] indicated that in the early state chalcopyrite was quickly reduced to chalcocite at a relatively low redox potential, but no reduced product can be detected at a high redox potential of about 550 mV (vs SCE). XRD patterns of their residues at different leaching stages were carried out to observe the change of generated products. The results indicated that leached residue after 5 days had obvious peaks of chalcocite Cu₂S, confirming the reduction of chalcopyrite according to Eq. (5). It is comparatively easy for chalcocite to be leached in the same condition. As time goes, the peaks of chalcocite disappear after 15 and 21 d chalcopyrite bioleaching. It is represented that chalcopyrite is difficult to be reduced to chalcocite during this period. The final copper extraction is much higher in the early states as the redox potential is located at its low point. Similar conclusion is drawn that the chalcocite might be a possible intermediate product during the leaching process [111, 124-127].

Therefore, one effect of redox potential is to prompt the formation of intermediated products, then increasing the dissolution rate of chalcopyrite. Based on the above discussion, a brief model for the effect of redox potential can be proposed in Figure 2.

3.3 Inhibiting formation of passivation layer

Redox potential in a suitable range can effectively inhibit the formation of passivation layer covered onto the chalcopyrite surface.

Many researchers [30, 61, 79, 128-133] indicated that the low dissolution rate of chalcopyrite mainly owed to the formation of passivation layer coated on the minerals surface, which led to the interaction of reagents with the surface of chalcopyrite becoming more difficult. No passivation layers of chalcopyrite surface were detected in a suitable potential range, whilst its dissolution rate increased greatly at about 420 mV (vs Ag/AgCl) rather than in a high potential range >600 mV [61]. Similar conclusions are drawn by CORDOBA et al [134-136], cyclic voltammetry (CV) studies of electrodes with different mass ratios of chalcopyrite to pyrite in sulfuric acid were designed to explain the dynamic process of the products on the surface [137]. It was shown that an obvious anodic peak could be found mainly due to the dissociation of chalcopyrite to the metal- deficient polysulfide, as shown in Eq. (11). It can be clearly known that the current density of peak significantly decreased with the addition of pyrite, confirming that the formation of passivation layer polysulfide onto the chalcopyrite surface was obviously inhibited by adding pyrite. In other word, the occurrence of Eq. (11) was inhibited by the addition of pyrite, thus resulting in fast dissolution of chalcopyrite.

Figure 2 A model for effect of redox potential in chalcopyrite leaching

CuFeS₂→Cu_1-xFe_1-yS₂+xCu²⁺+yFe²⁺+2(x+y)e^- (y>x)(11)

Therefore, one of the effects of redox potential is to inhibit the formation of passivation layers onto the chalcopyrite surface, leading to the higher copper extractions [138]. To combine the effects of redox potential and apply in complicated leaching solution, bacteria were considered. Figure 3 shows the dissolution and passivation mechanisms model for the effects of redox potential during chalcopyrite bioleaching by moderately thermophilic microorganisms.

4 Maintenance of redox potential

It is of great importance to find an eco-friendly way to maintain redox potential so that there is no side effect on chalcopyrite leaching, because redox potential plays a key role in chalcopyrite leaching. Therefore, the main attention of this part is to introduce how to maintain the redox potential in an optimum range, and give some brief comments on existing methods according to our work.

4.1 Using an electro-bioreactor

In order to deepen the understanding of electrochemical bioleaching for the treatment of complex sulfide ores and to use this understanding for analyzing the potential of this process for copper extraction, AHMADI et al [51] employed an electro-bioreactor to control the solution potential in the chalcopyrite leaching. The working electrode using was a reticulated Ti-Pt immersed into the cathodic compartment. The counter electrode was a Pt foil put into the anodic compartment. Ag/AgCl electrode was used as the reference electrode which was close to the working electrode. The potential of the working electrode was maintained with respect to the Ag/AgCl electrode using a potentiostat device. The author found that chalcopyrite can be effectively leached by controlling the redox potential at the range of 400-425 mV (vs. Ag/AgCl), and the copper recovery could be increased up to 35% compared to the chemical leaching and bioleaching. Under this condition, the precipitation of iron oxy-hydroxides onto the surface of chalcopyrite decreased significantly. Although this device can control the potential, some side effect on chalcopyrite leaching could occur such as higher energy consumption in industrial application, and the influence of reactive species ·OH based on the result from Refs. [139, 140].

4.2 Limiting oxygen concentration

THIRD et al [108] proposed that redox potential in the leaching solution can be controlled at a fixed setpoint by a computer-controlled solenoid valves with the oxygen limitation (air supply). The solenoid valves were used to control the redox potential through turning the airflow on or off based on whether the potential was lower or higher than the setpoint in the solution. In other word, redox potential was controlled at a fixed range using the oxygen limitation proposed during bioleaching of chalcopyrite. Redox potential fluctuations in response to the air supply during chalcopyrite bioleaching are shown in Figure 4. The horizontal line at 380 mV is the redox potential setpoint. The intermittent air supply is represented by the second horizontal line, perforations indicate air supply off and continuous line indicates air on. As long as the redox potential fell below the value of setpoint, the air supply was automatically switched on. Within seconds, the redox potential increased to above the setpoint as a result of oxidation from renewed ferrous iron to ferric iron. They found that the dissolution of chalcopyrite is prohibited by redox potential as high as 420 mV (vs Ag/AgCl) and a constant redox potential (380 mV vs Ag/AgCl) resulted in higher copper extractions of 52%-61% which was twice that of the former redox potential. Similar conclusions can be found in Ref. [141]. The main problem of this method, however, is that the tube is much easier to plug and damage in industrial application, although the air could be obtained easily.

Figure 3 A model for effects of redox potential in chalcopyrite bioleaching

Figure 4 Redox potential fluctuations in response to air supply during chalcopyrite bioleaching (solid black line)

4.3 Adding different ions

Fe³⁺ has been regarded as one of the most important oxidants for chalcopyrite dissolution, and its reaction product Fe²⁺ can be oxidized to Fe³⁺ by O₂ and/or microorganisms. In recent work [95], we studied the impact of Fe²⁺ and Fe³⁺ on chalcopyrite leaching. The redox potential can be controlled by the ratio of Fe²⁺ and Fe³⁺. The copper extractions increased with the addition of ferrous iron, but it decreased with the addition of ferric iron.Moreover, it was lower in the ferric sulfate solution than in blank solution. The initial redox potentials were 270, 420 and 510 mV for 0.1 mol/L Fe²⁺,0.05 mol/L Fe³⁺+0.05 mol/L Fe²⁺, and 0.1 mol/L Fe³⁺, respectively. In the last two items, the redox potential decreased with the leaching time as a result of the precipitation of ferric iron and/or reduction of ferric iron to ferrous iron. What is interesting is that it increased from 270 to 340 mV in the first 3 d (0.1 mol/L Fe²⁺), and then increased from 340 to 370 mV slowly. The recovery of copper from chalcopyrite in 0.1 mol/L Fe²⁺ solution was much higher than that in the 0.05 mol/L Fe³⁺ + 0.05 mol/L Fe²⁺, and 0.1 mol/L Fe³⁺ solutions. Therefore, high copper extractions can be obtained at a low redox potential, in other word, the low redox potential was beneficial to chalcopyrite leaching. Other similar works had been investigated to monitor potential and the rate of reduction Fe³⁺ by adding ferric ions, ferrous ions and cupric ions, and certain success achieved [142-144].

4.4 Adding chemical reagents like potassium permanganate or H₂O₂

NICOL et al [145] indicated that redox potential can be controlled through the injection of 0.05 mol/L potassium permanganate (K₂Cr₂O₇) solution. Redox potential was monitored using a Pt-ring electrode as working electrode with a combined Ag/AgCl electrode as a reference electrode (3 mol/L KCl). They indicated that the dissolution rate of pyrite was significantly higher at a potential of 850 mV than at 800 mV (vs SHE). A similar conclusion was drawn by CHANDRA et al [146] who used 15 wt.% H₂O₂ to control the solution redox potential at solution pH of 1, in the leaching media of HCl, H₂SO₄ and HClO₄. It can be known that the dissolution rate of pyrite was significant faster at solution redox potential of 900 mV (vs SHE) than at 700 mV. And they further found that the leaching rate of pyrite did not increase, although the activity of Fe³⁺ increased gradually. SUN et al [147] adjusted the redox potential to a setpoint with 15 wt.% H₂O₂, and found dissolution rate increased fivefold with increasing the redox potential by 100 mV. These investigations confirmed that the solution redox potential significantly affects the mineral dissolution, and can be controlled well by adding chemical reagents like potassium permanganate or H₂O₂ [148].

4.5 Adding ferric reductant

Pyrite (FeS₂, iron disulfide) is the most abundant and widespread sulfide mineral in the earth. O₂ and Fe³⁺ have been recognized as two of the most important oxidants for pyrite oxidation [142-144, 149-156]. Hence, we used pyrite to maintain the solution redox potential. The result for chalcopyrite bioleaching indicated that solution potential was in a relatively lower value after adding pyrite, and it decreased as the mass of pyrite increased. The best control effect is when the mass of pyrite was 3 g (the ratio of chalcopyrite and pyrite is 1:3). The redox potential consistently remains in a relatively stable value 350-370 mV (vs Ag/AgCl) in the first 25 d of bioleaching after adding 3 g pyrite. It arises from the dynamical balance between Fe³⁺ and Fe²⁺ concentration. From the results of copper extractions during bioleaching process, no significant difference was found when the mass ratio of chalcopyrite to pyrite was lower than 1:3. And their copper extractions are almost stagnant at about 27% after leaching for 30 d. However, the copper extractions promoted conspicuously and reached up to 70% when the mass ratio of chalcopyrite and pyrite is 1:3. The above results confirmed the conclusions that the optimum range of redox potential can accelerate the dissolution of chalcopyrite resulting in much higher copper extractions.

Based on the obtained results, a model for revealing the effect of pyrite in chalcopyrite bioleaching is proposed in Figure 5. When the redox potential E is lower than E_H, chalcopyrite can be reduced to the chalcocite which is oxidized quickly during bioleaching process. Then the higher copper extraction can be obtained. The proper amount of pyrite addition (high pyrite ratio) is helpful to control the redox potential at an optimal range, which can accelerate the reduction of chalcopyrite and the oxidation of chalcocite, and similar conclusions can be obtained from previous work [137]. Otherwise, for some other ferric reductant such as n-type or p-type chalcopyrite, ascorbic acid may be used to control the potential, and these works have been investigated in our group.

4.6 Adding iron removal agent

One of the most feasible schemes for controlling redox potential is to remove ferric (Fe³⁺) ions in the chalcopyrite leaching. The jarosite, hematite and goethite have been used as iron removing agent to remove iron from acidic solution [157, 158]. Thus, a strategy for controlling the redox potential in an appropriate range through the addition of limonite was proposed by our group and we found it promoted chalcopyrite dissolution through the removal of ferric (Fe³⁺) ions [159]. Its result for chalcopyrite bioleaching shows that the redox potential increased sharply in the first 5 d and reached a plateau in chalcopyrite bioleaching without adding limonite. Adversely, it can be well controlled at levels lower than 480 mV (vs Ag/AgCl) by adding limonite. Otherwise,chalcopyrite dissolved relatively fast in the first 5 d whilst the redox potential was relatively low in the bioleaching process without the addition of limonite. When it was added into the bioleaching solution, the copper extractions from chalcopyrite was significantly increased, indicating that the addition of iron removal agent can be used to control the redox potential and to prompt the dissolution of chalcopyrite.

Based on the above-mentioned discuss, a model for interpreting the strategy to accelerate the dissolution of chalcopyrite through the goethite precipitation process is proposed in Figure 6. The added limonite acted as a role of seed crystals, and induced the goethite precipitation process on the surface of crystal seeds. Otherwise, the precipitation process can remove ferric irons in solution and control the redox potential under an optimal range, thus accelerating the dissolution of chalcopyrite. Furthermore, the presence of crystal seeds can lead to the iron precipitation to occur on their surfaces, rather than the chalcopyrite surfaces, thus inhibiting the formation of passivation layer onto the surfaces of chalcopyrite.

5 Conclusions and prospect

1) Chalcopyrite has low extraction rate and low dissolution kinetics mainly because of the high lattice energy. Three common ways are briefly summarized to solve the problems: select the high effective bacteria, reduce the formation of passivation layers coated onto the surface of minerals, and control redox potential under an optimum range.

Figure 5 A model for revealing effect of pyrite in chalcopyrite bioleaching

Figure 6 A model for interpreting strategy to accelerate dissolution of chalcopyrite through goethite precipitation process [159]

2) The main effect of redox potential is to prompt the formation of intermediate products and to inhibit the formation of passivation products.

3) The controlling solution redox potential methods can be concluded to employing an electro-bioreactor, limiting oxygen input, adding different ions, adding chemical reagents like potassium permanganate and hydrogen peroxide, and adding ferric reductant or/and iron removal agents.

4) In the future, adding ferric reductant or/and iron removal agents will be a priority for us to solve the problems of high energy consumption caused by using electro-bioreactors and insecurity problems caused by adding chemical reagents (potassium permanganate and hydrogen peroxide).

References

[1] CORDOBA E M, MUNOZ J A, BLAZQUEZ M L, GONZALEZ F, BALLESTER A. Leaching of chalcopyrite with ferric ion. Part I: General aspects [J]. Hydrometallurgy, 2008, 93(3, 4): 81-87. DOI: 10.1016/j.hydromet.2008.04. 015.

[2] HARMER S L, THOMAS J E, FORNASIERO D, GERSON A R. The evolution of surface layers formed during chalcopyrite leaching [J]. Geochimica et Cosmochimica Acta, 2006, 70(17): 4392-4402. DOI: 0.1016/j.gca.2006.06.1555.

[3] LI Yu-biao, KAWASHIMA N, LI J, CHANDRA A P, GERSON A R. A review of the structure, and fundamental mechanisms and kinetics of the leaching of chalcopyrite [J]. Advances in Colloid and Interface Science, 2013, 197: 1-32. DOI: 10.1016/j.cis.2013.03.004.

[4] CHANG Ke-xin, ZHANG Yan-sheng, ZHANG Jia-ming, LI Teng-fei, WANG Jun, QIN Wen-qing. Effect of temperature-　induced phase transitions on bioleaching of chalcopyrite [J]. Transactions of Nonferrous Metals Society of China, 2019, 29(10): 2183-2191. DOI: /10.1016/s1003-6326(19)65124-1.

[5] WANG Jun, HU Ming-hao, ZHAO Hong-bo, TAO Lang, GAN Xiao-wen, QIN Wen-qing, QIU Guan-zhou. Well-controlled column bioleaching of a low-grade copper ore by a novel equipment [J]. Journal of Central South University, 2015, 22(9): 3318-3325. DOI: 10.1007/s11771- 015-2872-4.

[6] WATLING H R. Chalcopyrite hydrometallurgy at atmospheric pressure: 1. Review of acidic sulfate, sulfate–chloride and sulfate–nitrate process options [J]. Hydrometallurgy, 2013, 140: 163-180. DOI: 10.1016/ j.hydromet.2013.09.013.

[7] YANG Bao-jun, LUO Wen, WANG Xing-xing, YU Shi-chao, GAN Min, WANG Jun, LIU Xue-duan, QIU Guan-zhou. The use of biochar for controlling acid mine drainage through the inhibition of chalcopyrite biodissolution [J]. Science of the Total Environment, 2020, 139485. DOI: 10.1016/j.scitotenv. 2020.139485.

[8] OLIVEIRA D C, DUARTE H A. Disulphide and metal sulphide formation on the reconstructed (001) surface of chalcopyrite: A DFT study [J]. Applied Surface Science, 2010, 257(4): 1319-1324. DOI: 10.1016/j.apsusc.2010.08. 059.

[9] OERTZEN V G, HARMER S L, SKINNER W M. XPS and Ab initio calculation of surface states of sulfide minerals: Pyrite, chalcopyrite and molybdenite [J]. Molecular Simulation, 2006, 32(15): 1207-1212. DOI: 10.1080/ 08927020601081616.

[10] MIKHLIN Y, TOMASHEVICH Y, TAUSON V, VYALIKH D, MOLODTSOV S, SZARGAN R. A comparative X-ray absorption near-edge structure study of bornite, Cu₅FeS₄, and chalcopyrite, CuFeS₂ [J]. Journal of Electron Spectroscopy and Related Phenomena, 2005, 142(1): 83-88. DOI: 10.1016/j.elspec.2004.09.003.

[11] LLANOS J, BULJAN A, MUJICA C, RAMIREZ R. Electron transfer in the insertion of alkali metals in chalcopyrite [J]. Materials Research Bulletin, 1995, 30(1): 43-48. DOI: 10.1016/0025-5408(94)00105-7.

[12] VERA M, SCHIPPERS A, SAND W. Progress in bioleaching: Fundamentals and mechanisms of bacterial metal sulfide oxidation-Part A [J]. Applied Microbiology and Biotechnology, 2013, 97(17): 7529-7541. DOI: 10.1007/ s00253-013-4954-2.

[13] RAWLINGS D E, JOHNSON D B. Biomining [M]. New York: Springer, 2007.

[14] MISHRA D, KIM D, AHN J G, RHEE Y H. Bioleaching: A microbial process of metal recovery: A review [J]. Metals and Materials International, 2005, 11(3): 249-256. DOI: 10.1007/BF03027450.

[15] BRIERLEY J A, BRIERLEY C L. Present and future commercial applications of biohydrometallurgy [J]. Hydrometallurgy, 2001, 59(2): 233-239. DOI: 10.1016/ S0304-386X(00)00162-6.

[16] ZHAO Hong-bo, WANG Jun, GAN Xiao-wen, ZHENG Xi-hua, TAO Lang, HU Ming-hao, LI Yi-ni, QIN Wen-qing, QIU Guan-zhou. Effects of pyrite and bornite on bioleaching of two different types of chalcopyrite in the presence of Leptospirillum ferriphilum [J]. Bioresoure Technology, 2015, 194: 28-35. DOI: 10.1016/j.biortech.2015.07.003.

[17] JOHNSON D B. Biomining-biotechnologies for extracting and recovering metals from ores and waste materials [J]. Current Opinion in Biotechnology, 2014, 30: 24-31. DOI: 10.1016/j.copbio.2014.04.008.

[18] SCHIPPERS A, HEDRICH S, VASTERS J, DROBE M, SAND W, WILLSCHER S. Biomining: Metal recovery from ores with microorganisms [J]. Advances in Biochemical Engineering/Biotechnology, 2014, 141: 1-47. DOI: 10.1007/ 10_2013_216.

[19] HONG Mao-xin, WANG Xing-xing, WU Ling-bo, FANG Chao-jun, HUANG Xiao-tao, LIAO Rui, ZHAO Hong-bo, QIU Guan-zhou, WANG Jun. Intermediates transformation of bornite bioleaching by Leptospirillum ferriphilum and Acidithiobacillus caldus [J]. Minerals, 2019, 9(3): 159. DOI: 10.3390/min9030159.

[20] FANG Chao-jun, YU Shi-chao, WANG Xing-xing, ZHAO Hong-bo, QIN Wen-qing, QIU Guan-zhou, WANG Jun. Synchrotron radiation XRD investigation of the fine phase transformation during synthetic chalcocite acidic ferric sulfate leaching [J]. Minerals, 2018, 8(10): 461. DOI: 10.3390/min8100461.

[21] ZHAO Hong-bo, HUANG Xiao-tao, HU Ming-hao, ZHANG Chen-yang, ZHANG Yi-sheng, WANG Jun, QIN Wen-qing, QIU Guan-zhou. Insights into the surface transformation and electrochemical dissolution process of bornite in bioleaching [J]. Minerals, 2018, 8(4): 173. DOI: 10.3390/min8040173.

[22] YANG Cong-ren, QIN Wen-qing, LAI Shao-shi, WANG Jun, ZHANG Yan-sheng, JIAO Fen, REN Liu-yi, ZHUANG Tian, CHANG Zi-yong. Bioleaching of a low grade nickel- copper-cobalt sulfide ore [J]. Hydrometallurgy, 2011, 106(1， 2): 32-37. DOI: 10.1016/j.hydromet.2010.11.013.

[23] ZHEN Shi-jie, YAN Zhong-qiang, ZHANG Yan-sheng, WANG Jun, CAMPBELL Maurice, QIN Wen-qing. Column bioleaching of a low grade nickel-bearing sulfide ore containing high magnesium as olivine, chlorite and antigorite [J]. Hydrometallurgy, 2009, 96(4): 337-341. DOI: 10.1016/　j.hydromet.2008.11.007.

[24] QIN Wen-qing, ZHEN Shi-jie, YAN Zhong-qiang, CAMPBELL M, WANG Jun, LIU Kai, ZHANG Yan-sheng. Heap bioleaching of a low-grade nickel-bearing sulfide ore containing high levels of magnesium as olivine, chlorite and antigorite [J]. Hydrometallurgy, 2009, 98(1): 58-65. DOI: 10.1016/j.hydromet.2009.03.017.

[25] ZHEN Shi-jie, QIN Wen-qing, YAN Zhong-qiang, ZHANG Yan-sheng, WANG Jun, REN Liu-yi. Bioleaching of low grade nickel sulfide mineral in column reactor [J]. Transactions of Nonferrous Metals Society of China, 2008, 18(6): 1480-1484. DOI: 10.1016/S1003-6326(09)60029-7.

[26] LAN Zhuo-yue, HU Yue-hua, LIU Jian-she, WANG Jun. Solvent extraction of copper and zinc from bioleaching solutions with LIX984 and D2EHPA [J]. Journal of Central South University of Technology, 2005, 12(1): 45-49. DOI: 10.1007/s11771-005-0201-z.

[27] KLAUBER C. Fracture-induced reconstruction of a chalcopyrite (CuFeS₂) surface [J]. Surface and Interface Analysis, 2003, 35(5): 415-428. DOI: 10.1002/sia.1539.

[28] HE Huan, XIA Jin-lan, YANG Yi, JIANG Hong-chen, XIAO Chun-qiao, ZHENG Lei, MA Chen-yan, ZHAO Yi-dong, QIU Guan-zhou. Sulfur speciation on the surface of chalcopyrite leached by Acidianus manzaensis [J]. Hydrometallurgy, 2009, 99(1, 2): 45-50. DOI: 10.1016/ j.hydromet.2009.06.004.

[29] PANDA S, PARHI P K, NAYAK B D, PRADHAN N, MOHAPATRA U B, SUKLA L B. Two step meso-acidophilic bioleaching of chalcopyrite containing ball mill spillage and removal of the surface passivation layer [J]. Bioresource Technology, 2013, 130: 332-338. DOI: 10.1016/j.biortech.2012.12.071.

[30] ZHAO Hong-bo, WANG Jun, QIN Wen-qing, HU Ming-hao, ZHU Shan, QIU Guan-zhou. Electrochemical dissolution process of chalcopyrite in the presence of mesophilic microorganisms [J]. Minerals Engineering, 2015, 71: 159-169. DOI: 10.1016/j.mineng.2014.10.025.

[31] ZHAO Hong-bo, GAN Xiao-wen, WANG Jun, TAO Lang, QIN Wen-qing, QIU Guan-zhou. Stepwise bioleaching of Cu-Zn mixed ores with comprehensive utilization of silver-bearing solid waste through a new technique process [J]. Hydrometallurgy, 2017, 171: 374-386. DOI: 10.1016/j.hydromet.2017.06.002.

[32] ZHAO Hong-bo, HUANG Xiao-tao, WANG Jun, LI Yi-ni, LIAO Rui, WANG Xing-xing, QIU Xiao, XIONG Yu-ming, QIN Wen-qing, QIU Guan-zhou. Comparison of bioleaching and dissolution process of p-type and n-type chalcopyrite [J]. Minerals Engineering, 2017, 109: 153-161. DOI: 10.1016/ j.mineng.2017.03.013.

[33] ZHAO Hong-bo, WANG Jun, GAN Xiao-wen, HU Ming-hao, ZHANG Er-xing, QIN Wen-qing, QIU Guan-zhou. Cooperative bioleaching of chalcopyrite and silver-bearing tailing by mixed moderately thermophilic culture: An emphasis on the chalcopyrite dissolution with XPS and electrochemical analysis [J]. Minerals Engineering, 2015, 81: 29-39. DOI: 10.1016/j.mineng.2015.07.015.

[34] QIN Wen-qing, ZHANG Yan-sheng, ZHEN Shi-jie, WANG Jun, ZHANG Jian-wen, QIU Guan-zhou. Bioleaching of low-grade copper sulfide ore using a column reactor [J]. Advanced Materials Research, 2009, 71-73: 409-412. DOI: 10.4028/www.scientific.net/AMR.71-73.409.

[35] GERICKE M, GOVENDER Y, PINCHES A. Tank bioleaching of low-grade chalcopyrite concentrates using redox control [J]. Hydrometallurgy, 2010, 104(3, 4): 414-419. DOI: 10.1016/j.hydromet.2010.02.024.

[36] WANG Jun, TAO Lang, ZHAO Hong-bo, HU Ming-hao, ZHENG Xi-hua, PENG Hong, GAN Xiao-wen, XIAO Wei, CAO Pan, QIN Wen-qin, QIU Guan-zhou, WANG Dian-zuo. Cooperative effect of chalcopyrite and bornite interactions during bioleaching by mixed moderately thermophilic culture [J]. Minerals Engineering, 2016, 95: 116-123. DOI: 10.1016/j.mineng.2016.06.006.

[37] OLSON G J, BRIERLEY J A, BRIERLEY C L. Bioleaching review part B: Progress in bioleaching: Applications of microbial processes by the minerals industries [J]. Applied Microbiology and Biotechnology, 2003, 63(3): 249-257. DOI: 10.1007/s00253-003-1404-6.

[38] ROHWERDER T, GEHRKE T, KINZLER K, SAND W. Bioleaching review part A: Progress in bioleaching: Fundamentals and mechanisms of bacterial metal sulfide oxidation [J]. Applied Microbiology and Biotechnology, 2003, 63(3): 239-248. DOI: 10.1007/s00253-003-1448-7.

[39] BRIERLEY C L, BRIERLEY J A. Progress in bioleaching: Part B: Applications of microbial processes by the minerals industries [J]. Applied Microbiology and Biotechnology, 2013, 97(17): 7543-7552. DOI: 10.1007/s00253-013- 5095-3.

[40] WANG Xing-xing, LIAO Rui, ZHAO Hong-bo, HONG Mao-xing, HUANG Xiao-tao, PENG Hong, WEN Wen, QIN Wen-qing, QIU Guan-zhou, HUANG Cao-ming, WANG Jun. Synergetic effect of pyrite on strengthening bornite bioleaching by Leptospirillum ferriphilum [J]. Hydrometallurgy, 2018, 176: 9-16. DOI: 10.1016/ j.hydromet.2017.12.003.

[41] WANG Jun, ZHAO Hong-bo, QIN Wen-qing, QIU Guan- zhou. Bioleaching of complex polymetallic sulfide ores by mixed culture [J]. Journal of Central South University, 2014, 21(7): 2633-2637. DOI: 10.1007/s11771-014-2223-x.

[42] WANG Jun, ZHAO Hong-bo, ZHUANG Tian, QIN Wen- qing, ZHU Shan, QIU Guan-zhou. Bioleaching of Pb–Zn–Sn chalcopyrite concentrate in tank bioreactor and microbial community succession analysis [J]. Transactions of Nonferrous Metals Society of China, 2013, 23(12): 3758-3762. DOI: 10.1016/s1003-6326(13)62926-x.

[43] CHEN Bo-wei, WU Biao, LIU Xing-yu, WEN Jian-kang. Comparison of microbial diversity during column bioleaching of chalcopyrite at different temperatures [J]. Journal of Basic Microbiology, 2014, 54(6): 491-499. DOI: 10.1002/jobm.201300092.

[44] GU Guo-hua, HU Ke-ting, LI Shuang-ke. Bioleaching and electrochemical properties of chalcopyrite by pure and mixed culture of Leptospirillum ferriphilum and Acidthiobacillus thiooxidans [J]. Journal of Central South University, 2013, 20(1): 178-183. DOI: 10.1007/s11771-013-1474-2.

[45] HUANG Yu-lin, ZHANG Yi-sheng, ZHAO Hong-bo, ZHANG Yan-jun, XIONG Yu-ming, ZHANG Lu-yuan, ZHOU Jun, WANG Jun, QIN Wen-qing, QIU Guan-zhou. Bioleaching of chalcopyrite-bornite and chalcopyrite-pyrite mixed ores in the presence of moderately thermophilic microorganisms [J]. International Journal of Electrochemical Science, 2017, 12(11): 10493-10510. DOI: 10.20964/ 2017.11.33.

[46] LIANG Yu-ting, ZHU Shan, WANG Jun, AI Chen-bing, QIN Wen-qing. Adsorption and leaching of chalcopyrite by Sulfolobus metallicus YN24 cultured in the distinct energy sources [J]. International Journal of Minerals, Metallurgy, and Materials, 2015, 2(6): 549-552. DOI: 10.1007/s12613- 015-1106-y.

[47] QIN Wen-qing, LIU Kai, DIAO Meng-xue, WANG Jun, ZHANG Yan-sheng, YANG Cong-ren, JIAO Fen. Oxidation of arsenite (As(III)) by ferric iron in the presence of pyrite and a mixed moderately thermophilic culture [J]. Hydrometallurgy, 2013, 137: 53-59. DOI: 10.1016/ j.hydromet.2013.05.011.

[48] RODRIGUEZ Y, BALLESTER A, BLAZQUEZ M L, GONZALEZ F, MUNOZ J A. Study of bacterial attachment during the bioleaching of pyrite, chalcopyrite, and sphalerite [J]. Geomicrobiology Journal, 2003, 20(2): 131-141. DOI: 10.1080/01490450390193246.

[49] MOUSAVI S M, YAGHMAEI S, VOSSOUGHI M, JAFARI A. Efficiency of copper bioleaching of two mesophilic and thermophilic bacteria isolated from chalcopyrite concentrate of kerman-yazd regions in Iran [J]. Scientia Iranica, 2007, 14(2): 180-184.

[50] MARHUAL N P, PRADHAN N, KAR R N, SUKLA L B, MISHRA B. Differential bioleaching of copper by mesophilic and moderately thermophilic acidophilic consortium enriched from same copper mine water sample [J]. Bioresource Technology, 2008, 99(17): 8331-8336. DOI: 10.1016/j.biortech.2008.03.003.

[51] AHMADI A, SCHAFFIE M, MANAFI Z, RANJBAR M. Electrochemical bioleaching of high grade chalcopyrite flotation concentrates in a stirred bioreactor [J]. Hydrometallurgy, 2010, 104(1): 99-105. DOI: 10.1016/ j.hydromet.2010.05.001.

[52] LEE J, ACAR S, DOERR D L, BRIERLEY J A. Comparative bioleaching and mineralogy of composited sulfide ores containing enargite, covellite and chalcocite by mesophilic and thermophilic microorganisms [J]. Hydrometallurgy, 2011, 105(3, 4): 213-221. DOI: 10.1016/ j.hydromet.2010.10.001.

[53] TUPIKINA O V, MINNAAR S H, van HILLE R P, van WYK N, RAUTENBACH G F, DEW D, HARRISON S T L. Determining the effect of acid stress on the persistence and growth of thermophilic microbial species after mesophilic colonisation of low grade ore in a heap leach environment [J]. Minerals Engineering, 2013, 53: 152-159. DOI: 10.1016/ j.mineng.2013.07.015.

[54] ABDOLLAHI H, SHAFAEI S Z, NOAPARAST M, MANAFI Z, NIEMELA S I, TUOVINEN O H. Mesophilic and thermophilic bioleaching of copper from a chalcopyrite-containing molybdenite concentrate [J]. International Journal of Mineral Processing, 2014, 128: 25-32. DOI: 10.1016/j.minpro.2014.02.003.

[55] TUPIKINA O V, MINNAAR S H, RAUTENBACH G F, DEW D W, HARRISON S T L. Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles [J]. Hydrometallurgy, 2014, 149: 244-251. DOI: 10.1016/ j.hydromet.2013.10.010.

[56] NIE Zhen-yuan, LIU Hong-chang, XIA Jin-lan, YANG Yi, ZHEN Xiang-jun, ZHANG Li-juan, QIU Guan-zhou. Evidence of cell surface iron speciation of acidophilic iron-oxidizing microorganisms in indirect bioleaching process [J]. Biometals, 2016, 29(1): 25-37. DOI: 10.1007/ s10534-015-9893-1.

[57] AKCIL A, CIFTCI H, DEVECI H. Role and contribution of pure and mixed cultures of mesophiles in bioleaching of a pyritic chalcopyrite concentrate [J]. Minerals Engineering, 2007, 20(3): 310-318. DOI: 10.1016/j.mineng.2006.10.016.

[58] ABDOLLAHI H, NOAPARAST M, SHAFAEI S Z, MANAFI Z, MUNOZ J A, TUOVINEN O H. Silver- catalyzed bioleaching of copper, molybdenum from a chalcopyrite-molybdenite concentrate [J]. International Biodeterioration & Biodegradation, 2015, 104: 194-200. DOI: 10.1016/j.ibiod.2015.05.025.

[59] YANG Yi, HARMER S, CHEN Miao. Synchrotron X-ray photoelectron spectroscopic study of the chalcopyrite leached by moderate thermophiles and mesophiles [J]. Minerals Engineering, 2014, 69: 185-195. DOI: 10.1016/ j.mineng.2014.08.011.

[60] BOXALL N J, REA S, LI Jian, MORRIS C, KAKSONEN A H. Effect of high sulfate concentrations on chalcopyrite bioleaching and molecular characterisation of the bioleaching microbial community [J]. Hydrometallurgy, 2017, 168: 32-39. DOI: 10.1016/j.hydromet.2016.07.006.

[61] SANDSTROM A, SHCHUKAREV A, PAUL J. XPS characterisation of chalcopyrite chemically and bio-leached at high and low redox potential [J]. Minerals Engineering, 2005, 18(5): 505-515. DOI: 10.1016/j.mineng.2004.08.004.

[62] RUBIO A, FRUTOS F J G. Bioleaching capacity of an extremely thermophilic culture for chalcopyritic materials [J]. Minerals Engineering, 2002, 15(9): 689-694. DOI: 10.1016/ S0892-6875(02)00124-3.

[63] D'HUGUES P, FOUCHER S, GALLE-CAVALLONI P, MORIN D. Continuous bioleaching of chalcopyrite using a novel extremely thermophilic mixed culture [J]. International Journal of Mineral Processing, 2002, 66(1-4): 107-119. DOI: 10.1016/S0301-7516(02)00004-2.

[64] GERICKE M, PINCHES A, ROOYEN J V V. Bioleaching of a chalcopyrite concentrate using an extremely thermophilic culture [J]. International Journal of Mineral Processing, 2001, 62(1-4): 243-255. DOI: 10.1016/S0301-7516(00)00056-9.

[65] GOMEZ E, BALLESTER A, GONZALEZ F, BLAZQUEZ M L. Leaching capacity of a new extremely thermophilic microorganism, Sulfolobus rivotincti [J]. Hydrometallurgy, 1999, 52(3): 349-366. DOI: 10.1016/S0304-386X(99)　00027-4.

[66] ZENG Wei-min, QIU Guan-zhou, ZHOU Hong-bo, PENG Juan-hua, CHEN Miao, TAN S N, CHAO Wei-liang, LIU Xue-duan, ZHANG Yan-sheng. Community structure and dynamics of the free and attached microorganisms during moderately thermophilic bioleaching of chalcopyrite concentrate [J]. Bioresource Technology, 2010, 101(18): 7068-7075. DOI: 10.1016/j.biortech.2010.04.003.

[67] WANG Jun, QIN Wen-qing, ZHANG Yan-sheng, YANG Cong-ren. Bacterial leaching of chalcopyrite and bornite with native bioleaching microorganism [J]. Transactions of Nonferrous Metals Society of China, 2008, 18(6): 1468-1472. DOI: 10.1016/S1003-6326(09)60027-3.

[68] ZHANG Yan-sheng, QIN Wen-qing, WANG Jun, ZHEN Shi-jie, YANG Cong-ren, ZHANG Jian-wen, NAI Shao-shi, QIU Guan-zhou. Bioleaching of chalcopyrite by pure and mixed culture [J]. Transactions of Nonferrous Metals Society of China, 2008, 18(6): 1491-1496. DOI: 10.1016/S1003- 6326(09)60031-5.

[69] HU Ke-ting, GU Guo-hua, LI Shuang-ke, QIU Guan-zhou. Bioleaching of chalcopyrite by Leptospirillum ferriphilum [J]. Journal of Central South University, 2012, 19(6): 1718-1723. DOI: 10.1007/s11771-012-1198-8.

[70] WANG Jun, QIU Guan-zhou, QIN Wen-qing, ZHANG Yan-sheng. Microbial leaching of marmatite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans [J]. Transactions of Nonferrous Metals Society of China, 2006, 16(4): 937-942. DOI: 10.1016/S1003- 6326(06)60355-5.

[71] WATLING H R. The bioleaching of sulphide minerals with emphasis on copper sulphides—A review [J]. Hydrometallurgy, 2006, 84(1, 2): 81-108. DOI: 10.1016/ j.hydromet.2006.05.001.

[72] YIN Sheng-hua, WANG Lei-ming, KABWE E, CHEN Xun, YAN Rong-fu, AN Kai, ZHANG Lei, WU Ai-xiang. Copper bioleaching in China: Review and prospect [J]. Minerals, 2018, 8(2): 32. DOI: 10.3390/min8020032.

[73] FANG Jing-hua, LIU Yong, HE Wan-li, QIN Wen-qing, QIU Guan-zhou, WANG Jun. Transformation of iron in pure culture process of extremely acidophilic microorganisms [J]. Transactions of Nonferrous Metals Society of China, 2017, 27(5): 1150-1155. DOI: 10.1016/s1003-6326(17)60134-1.

[74] BRIERLEY C L, BRIERLEY J A. Progress in bioleaching: Part B: Applications of microbial processes by the minerals industries [J]. Applied Microbiology and Biotechnology, 2013, 97(17): 7543-7552. DOI: 10.1007/s00253-013-5095-3

[75] DUTRIZAC J E. Elemental sulphur formation during the ferric sulphate leaching of chalcopyrite [J]. Canadian Metallurgical Quarterly, 1989, 28(4): 337-344. DOI: 10.1179/cmq.1989.28.4.337.

[76] ZHAO Hong-bo, ZHANG Yi-sheng, ZHANG Xian, QIAN Lu, SUN Meng-lin, YANG Yu, ZHANG Yan-sheng, WANG Jun, KIM H, QIU Guan-zhou. The dissolution and passivation mechanism of chalcopyrite in bioleaching: An overview [J]. Minerals Engineering, 2019, 136: 140-154. DOI: 10.1016/j.mineng.2019.03.014.

[77] FU Kai-bin, LIN Hai, MO Xiao-lan, WANG Han, WEN Hong-wei, WEN Zi-long. Comparative study on the passivation layers of copper sulphide minerals during bioleaching [J]. International Journal of Minerals Metallurgy and Materials, 2012, 19(10): 886-892. DOI: 10.1007/ s12613-012-0643-x.

[78] YANG Yi, HARMER S L, CHEN Miao. Synchrotron-based XPS and NEXAFS study of surface chemical species during electrochemical oxidation of chalcopyrite [J]. Hydrometallurgy, 2015, 156: 89-98. DOI: 10.1016/ j.hydromet.2015.05.011.

[79] KLAUBER C. A critical review of the surface chemistry of acidic ferric sulphate dissolution of chalcopyrite with regards to hindered dissolution [J]. International Journal of Mineral Processing, 2008, 86(1-4): 1-17. DOI: 10.1016/j.minpro. 2007.09.003.

[80] YANG Bao-jun, ZHAO Chun-xiao, LUO Wen, LIAO Rui, GAN Min, WANG Jun, LIU Xue-duan, QIU Guan-zhou. Catalytic effect of silver on copper release from chalcopyrite mediated by Acidithiobacillus ferrooxidans [J]. Journal of Hazardous Materials, 2020, 392: 122290. DOI: 10.1016/j.jhazmat.2020.122290.

[81] YANG Bao-jun, LIN Mo, FANG Jing-hua, ZHANG Rui-yong, LUO Wen, WANG Xing-xing, LIAO Rui, WU Bai-qiang, WANG Jun, GAN Min. Combined effects of jarosite and visible light on chalcopyrite dissolution mediated by Acidithiobacillus ferrooxidans [J]. Science of the Total Environment, 2020, 698: 134175. DOI: 10.1016/j.scitotenv.2019.134175.

[82] YANG Yi, LIU Wei-hua, CHEN Miao. XANES and XRD study of the effect of ferrous and ferric ions on chalcopyrite bioleaching at 30 °C and 48 °C [J]. Minerals Engineering, 2015, 70: 99-108. DOI: 10.1016/j.mineng.2014.08.021.

[83] YANG Yi, LIU Wei-hua, CHEN Miao. A copper and iron K-edge XANES study on chalcopyrite leached by mesophiles and moderate thermophiles [J]. Minerals Engineering, 2013, 48: 31-35. DOI: 10.1016/j.mineng. 2013.01.010.

[84] WANG Jun, GAN Xiao-wen, ZHAO Hong-bo, HU Ming-hao, LI Kai-yun, QIN Wen-qing, QIU Guan-zhou. Dissolution and passivation mechanisms of chalcopyrite during bioleaching: DFT calculation, XPS and electrochemistry analysis [J]. Minerals Engineering, 2016, 98: 264-278. DOI: 10.1016/j.mineng.2016.09.008.

[85] WU Shi-fa, YANG Cong-ren, QIN Wen-qing, JIAO Fen, WANG Jun, ZHANG Yan-sheng. Sulfur composition on surface of chalcopyrite during its bioleaching at 50 °C [J]. Transactions of Nonferrous Metals Society of China, 2015, 25(12): 4110-4118. DOI: 10.1016/s1003-6326(15) 64062-6.

[86] KHOSHKHOO M, DOPSON M, SHCHUKAREV A, SANDSTROM A. Chalcopyrite leaching and bioleaching: An X-ray photoelectron spectroscopic (XPS) investigation on the nature of hindered dissolution [J]. Hydrometallurgy, 2014, 149: 220-227. DOI: 10.1016/j.hydromet.2014.08.012.

[87] LIU Hong-chang, XIA Jin-lan, NIE Zhen-yuan. Relatedness of Cu and Fe speciation to chalcopyrite bioleaching by Acidithiobacillus ferrooxidans [J]. Hydrometallurgy, 2015, 156: 40-46. DOI: 10.1016/j.hydromet.2015.05.013.

[88] ZHAO Hong-bo, WANG Jun, HU Ming-hao, QIN Wen-qing, ZHANG Yan-sheng, QIU Guan-zhou. Synergistic bioleaching of chalcopyrite and bornite in the presence of Acidithiobacillus ferrooxidans [J]. Bioresource Technology, 2013, 149(4): 71-76. DOI: 10.1016/j.biortech.2013.09.035.

[89] LI Yu-biao, QIAN Gu-jie, LI Jun, GERSON A R. Kinetics and roles of solution and surface species of chalcopyrite dissolution at 650 mV [J]. Geochimica et Cosmochimica Acta, 2015, 161: 188-202. DOI: 10.1016/j.gca.2015.04.012.

[90] ZHAO Hong-bo, WANG Jun, QIN Wen-qing, HU Ming-hao, QIU Guan-zhou. Electrochemical dissolution of chalcopyrite concentrates in stirred reactor in the presence of Acidithiobacillus ferrooxidans [J]. International Journal of Electrochemical Science, 2015, 10(1): 848-858. DOI: 10.1.1.666.6424.

[91] YANG Yi, HARMER S, CHEN Miao. Synchrotron-based XPS and NEXAF study of surface chemical species during electrochemical oxidation of chalcopyrite [J]. Hydrometallurgy, 2015, 156: 89-98. DOI: 10.1016/ j.hydromet.2015.05.011.

[92] YU Run-lan, ZHONG Dai-li, MIAO Lei, WU Fa-deng, QIU Guan-zhou, GU Guo-hua. Relationship and effect of redox potential, jarosites and extracellular polymeric substances in bioleaching chalcopyrite by Acidithiobacillus ferrooxidans [J]. Transactions of Nonferrous Metals Society of China, 2011, 21(7): 1634-1640. DOI: 10.1016/s1003-6326(11) 60907-2.

[93] KAPLUN K, LI Jian-chun, KAWASHIMA N, GERSON A R. Cu and Fe chalcopyrite leach activation energies and the effect of added Fe³⁺ [J]. Geochimica et Cosmochimica Acta, 2011, 75(20): 5865-5878. DOI: 10.1016/j.gca.2011.07.003.

[94] LI Jian-chun, KAWASHIMA N, KAPLUN K, ABSOLON V J, GERSON A R. Chalcopyrite leaching: The rate controlling factors [J]. Geochimica et Cosmochimica Acta, 2010, 74(10): 2881-2893. DOI: 10.1016/j.gca.2010.02.029.

[95] YANG Cong-ren, QIN Wen-qing, ZHAO Hong-bo, WANG Jun, WANG Xing-jie. Mixed potential plays a key role in leaching of chalcopyrite: Experimental and theoretical analysis [J]. Industrial & Engineering Chemistry Research, 2018, 57(5): 1733-1744. DOI: 10.1021/acs.iecr.7b02051.

[96] WANG Jun, LIAO Rui, TAO Lang, ZHAO Hong-bo, ZHAI Rui, QIN Wen-qing, QIU Guan-zhou. A comprehensive utilization of silver-bearing solid wastes in chalcopyrite bioleaching [J]. Hydrometallurgy, 2017, 169: 152-157. DOI: 10.1016/j.hydromet.2017.01.006.

[97] KHOSHKHOO M, DOPSON M, ENGSTROM F, SANDSTROM A. New insights into the influence of redox potential on chalcopyrite leaching behaviour [J]. Minerals Engineering, 2017, 100: 9-16. DOI: 10.1016/j.mineng. 2016.10.003.

[98] CORDOBA E M, MUNOZ J A, BLAZQUEZ M L, GONZALEZ F, BALLESTER A. Leaching of chalcopyrite with ferric ion. Part IV: The role of redox potential in the presence of mesophilic and thermophilic bacteria [J]. Hydrometallurgy, 2008, 93: 106-115. DOI: 10.1016/ j.hydromet.2007.11.005.

[99] KHOSHKHOO M, DOPSON M, SHCHUKAREV A, SANDSTROM A. Electrochemical simulation of redox potential development in bioleaching of a pyritic chalcopyrite concentrate [J]. Hydrometallurgy, 2014, 144: 7-14. DOI: 10.1016/j.hydromet.2013.12.003.

[100] LOTFALIAN M, RANJBAR M, FAZAELIPOOR M H, SCHAFFIE M, MANAFI Z. The effect of redox control on the continuous bioleaching of chalcopyrite concentrate [J]. Minerals Engineering, 2015, 81: 52-57. DOI: 10.1016/ j.mineng.2015.07.006.

[101] QIN Wen-qing, YANG Cong-ren, WANG Jun, ZHANG Yan-sheng, JIAO Fen, ZHAO Hong-bo, ZHU Shan. Effect of Fe²⁺ and Cu²⁺ ions on the electrochemical behavior of massive chalcopyrite in bioleaching system [J]. Advanced Materials Research, 2013, 825: 472-476. DOI: 10.4028/ www.scientific.net/AMR.825.472.

[102] HIROYOSHI N, TSUNEKAWA M, OKAMOTO H, NAKAYAMA R, KUROIWA S. Improved chalcopyrite leaching through optimization of redox potential [J]. Canadian Metallurgical Quarterly, 2008, 47(3): 253-258. DOI: 10.1179/cmq.2008.47.3.253.

[103] HIROYOSHI N, KITAGAWA H, TSUNEKAWA M. Effect of solution composition on the optimum redox potential for chalcopyrite leaching in sulfuric acid solutions [J]. Hydrometallurgy, 2008, 91(1-4): 144-149. DOI: 10.1016/ j.hydromet.2007.12.005.

[104] HIROYOSHI N, KUROIWA S, MIKI H, TSUNEKAWA M, HIRAJIMA T. Synergistic effect of cupric and ferrous ions on active-passive behavior in anodic dissolution of chalcopyrite in sulfuric acid solutions [J]. Hydrometallurgy, 2004, 74(1, 2): 103-116. DOI: 10.1016/j.hydromet.2004. 01.003.

[105] HIROYOSHI N, KUROIWA S, MIKI H, TSUNEKAWA M, HIRAJIMA T. Effects of coexisting metal ions on the redox potential dependence of chalcopyrite leaching in sulfuric acid solutions [J]. Hydrometallurgy, 2007, 87(1, 2): 1-10. DOI: 10.1016/j.hydromet.2006.07.006.

[106] HIROYOSHI N, MIKI H, HIRAJIMA T, TSUNEKAWA M. Enhancement of chalcopyrite leaching by ferrous ions in acidic ferric sulfate solutions [J]. Hydrometallurgy, 2001, 60(3): 185-197. DOI: 10.1016/s0304-386x(00)00155-9.

[107] PETERSEN J, DIXON D G. Competitive bioleaching of pyrite and chalcopyrite [J]. Hydrometallurgy, 2006, 83(1-4): 40-49. DOI: 10.1016/j.hydromet.2006.03.036.

[108] THIRD K A, CORD-RUWISCH R, WATLING H R. Control of the redox potential by oxygen limitation improves bacterial leaching of chalcopyrite [J]. Biotechnology and Bioengineering, 2002, 78(4): 433-441. DOI: 10.1002/ bit.10184.

[109] ZHAO Hong-bo, WANG Jun, YANG Cong-ren, HU Ming-hao, GAN Xiao-wen, TAO Lang, QIN Wen-qing, QIU Guan-zhou. Effect of redox potential on bioleaching of chalcopyrite by moderately thermophilic bacteria: An emphasis on solution compositions [J]. Hydrometallurgy, 2015, 151: 141-150. DOI: 10.1016/j.hydromet.2014.11.009.

[110] BEVILAQUA D, LAHTI-TOMMILA H, GARCIA O Jr, PUHAKKA J A, TUOVINEN O H. Bacterial and chemical leaching of chalcopyrite concentrates as affected by the redox potential and ferric/ferrous iron ratio at 22 °C [J]. International Journal of Mineral Processing, 2014, 132: 1-7. DOI: 10.1016/j.minpro.2014.08.008.

[111] QIN Wen-qing, YANG Cong-ren, LAI Shao-shi, WANG Jun, KAI Liu, BO Zhang. Bioleaching of chalcopyrite by moderately thermophilic microorganisms [J]. Bioresource Technology, 2013, 129(2): 200-208. DOI: 10.1016/j.biortech. 2012.11.050.

[112] DELAUNERD,REDDYKR.Encyclopediaofsoilsintheenvironment [M]. Elsevier, 2005. DOI: 10.1016/B0-12- 348530-4/00212-5.

[113] VANLOON G W, DUFFY S J. Environmental chemistry: A global perspective [M]. Oxford: Oxford University Press, 2010.

[114] HIROYOSHI N, MIKI H, HIRAJIMA T, TSUNEKAWA M. A model for ferrous-promoted chalcopyrite leaching [J]. Hydrometallurgy, 2000, 57(1): 31-38. DOI: 10.1016/ s0304-386x(00)00089-x.

[115] ELSHERIEF A E. The influence of cathodic reduction, Fe²⁺ and Cu²⁺ ions on the electrochemical dissolution of chalcopyrite in acidic solution [J]. Minerals Engineering, 2002, 15(4): 215-223. DOI: 10.1016/s0892-6875(01) 00208-4.

[116] GU Guo-hua, HU Ke-ting, ZHANG Xun, XIONG Xian-xue, YANG Hui-sha. The stepwise dissolution of chalcopyrite bioleached by Leptospirillum ferriphilum [J]. Electrochimica Acta, 2013, 103: 50-57. DOI: 10.1016/j.electacta.2013.04. 051.

[117] GU Guo-hua, XIONG Xian-xue, HU Ke-ting, LI Shuang-ke, WANG Chong-qing. Stepwise dissolution of chalcopyrite bioleaching by thermophile A.manzaensis and mesophile L.ferriphilum [J]. Journal of Central South University, 2015, 22(10): 3751-3759. DOI: 10.1007/s11771-015-2919-6.

[118] ZHAO Hong-bo, HU Ming-hao, LI Yi-ni, ZHU Shan, QIN Wen-qing, QIU Guan-zhou, WANG Jun. Comparison of electrochemical dissolution of chalcopyrite and bornite in acid culture medium [J]. Transactions of Nonferrous Metals Society of China, 2015, 25(1): 303-313. DOI: 10.1016/ S1003-6326(15)63605-6.

[119] LIU Hong-chang, NIE Zhen-yuan, XIA Jin-lan, ZHU Hong-rui, YANG Yun, ZHAO Chang-hui, ZHENG Lei, ZHAO Yi-dong. Investigation of copper, iron and sulfur speciation during bioleaching of chalcopyrite by moderate thermophile Sulfobacillus thermosulfidooxidans [J]. International Journal of Mineral Processing, 2015, 137: 1-8. DOI: 10.1016/j.minpro.2015.02.008.

[120] ZENG Wei-min, QIU Guan-zhou, CHEN Miao. Investigation of Cu-S intermediate species during electrochemical dissolution and bioleaching of chalcopyrite concentrate [J]. Hydrometallurgy, 2013, 134: 158-165. DOI: 10.1016/j.hydromet.2013.02.009.

[121] WOODS R, YOON R H, YOUNG C A. E_h-pH diagrams for stable and metastable phases in the copper-sulfur-water system [J]. International Journal of Mineral Processing, 1987, 20(1, 2): 109-120. DOI: 10.1016/0301-7516(87)90020-2.

[122] LEE M S, NICOL M J, BASSON P. Cathodic processes in the leaching and electrochemistry of covellite in mixed sulfate-chloride media [J]. Journal of Applied Electrochemistry, 2008, 38(3): 363-369. DOI: 10.1007/ s10800-007-9447-5.

[123] HIROYOSHI N, ARAI M, MIKI H, TSUNEKAWA M, HIRAJIMA T. A new reaction model for the catalytic effect of silver ions on chalcopyrite leaching in sulfuric acid solutions [J]. Hydrometallurgy, 2002, 63(3): 257-267. DOI: 10.1016/s0304-386x(01)00228-6.

[124] ARCE E A, GONZALEZ I. A comparative study of electrochemical behavior of chalcopyrite, chalcocite and bornite in sulfuric acid solution [J]. International Journal of Mineral Processing, 2002, 67(1-4): 17-28. DOI: 10.1016/ s0301-7516(02)00003-0.

[125] VILCAEZ J, SUTO K, INOUE C. Bioleaching of chalcopyrite with thermophiles: Temperature-pH-ORP dependence [J]. International Journal of Mineral Processing, 2008, 88(1, 2): 37-44. DOI: 10.1016/j.minpro.2008.06.002.

[126] VILCAEZ J, YAMADA R, INOUE C. Effect of pH reduction and ferric ion addition on the leaching of chalcopyrite at thermophilic temperatures [J]. Hydrometallurgy, 2009, 96(1, 2): 62-71. DOI: 10.1016/ j.hydromet.2008.08.003.

[127] LIANG Chang-li, XIA Jin-lan, YANG Yi, NIE Zhen-yuan, ZHAO Xiao-juan, ZHENG Lei, MA Chen-yan, ZHAO Yi-dong. Characterization of the thermo-reduction process of chalcopyrite at 65 °C by cyclic voltammetry and XANES spectroscopy [J]. Hydrometallurgy, 2011, 107(1, 2): 13-21. DOI: 10.1016/j.hydromet.2011.01.011.

[128] ZENG Wei-min, QIU Guan-zhou, ZHOU Hong-bo, CHEN Miao. Electrochemical behaviour of massive chalcopyrite electrodes bioleached by moderately thermophilic microorganisms at 48 °C [J]. Hydrometallurgy, 2011, 105(3, 4): 259-263. DOI: 10.1016/j.hydromet.2010.10.012.

[129] BEVILAQUA D, DIEZ-PEREZ I, FUGIVARA CS, SANZ F, BENEDETTI A V, GARCIA O. Oxidative dissolution of chalcopyrite by Acidithiobacillus ferrooxidans analyzed by electrochemical impedance spectroscopy and atomic force microscopy [J]. Bioelectrochemistry, 2004, 64(1): 79-84. DOI: 10.1016/j.bioelechem.2004.01.006.

[130] ZHAO Hong-bo, WANG Jun, QIN Wen-qing, ZHENG Xi-hua, TAO Lang, GAN Xiao-wen, QIU Guan-zhou. Surface species of chalcopyrite during bioleaching by moderately thermophilic bacteria [J]. Transactions of Nonferrous Metals Society of China, 2015, 25(8): 2725-2733. DOI: 10.1016/s1003-6326(15)63897-3.

[131] LIU Qing-you, CHEN Miao, YANG Yi. The effect of chloride ions on the electrochemical dissolution of chalcopyrite in sulfuric acid solutions [J]. Electrochimica Acta, 2017, 253: 257-267. DOI: 10.1016/j.electacta.2017. 09.063.

[132] BEVILAQUA D, LAHTI-TOMMILA H, GARCIA O Jr, PUHAKKA J A, TUOVINEN O H. Bacterial and chemical leaching of chalcopyrite concentrates as affected by the redox potential and ferric/ferrous iron ratio at 22 °C [J]. International Journal of Mineral Processing, 2014, 132: 1-7. DOI: 10.1016/j.minpro.2014.08.008.

[133] GU Guo-hua, HU Ke-ting, LI Shuang-ke. Surface characterization of chalcopyrite interacting with Leptospirillum ferriphilum [J]. Transactions of Nonferrous Metals Society of China, 2014, 24(6): 1898-1904. DOI: 10.1016/s1003-6326(14)63269-6.

[134] CORDOBA E M, MUNOZ J A, BLAZQUEZ M L, GONZALEZ F, BALLESTER A. Leaching of chalcopyrite with ferric ion. Part III: Effect of redox potential on the silver-catalyzed process [J]. Hydrometallurgy, 2008, 93(3, 4): 97-105. DOI: 10.1016/j.hydromet.2007.11.006.

[135] CORDOBA E M, MUNOZ J A, BLAZQUEZ M L, GONZALEZ F, BALLESTER A. Leaching of chalcopyrite with ferric ion. Part II: Effect of redox potential [J]. Hydrometallurgy, 2008, 93(3, 4): 88-96. DOI: 10.1016/ j.hydromet.2008.04.016.

[136] CORDOBA E M, MUNOZ J A, BLAZQUEZ M L, GONZALEZ F, BALLESTER A. Leaching of chalcopyrite with ferric ion. Part IV: The role of redox potential in the presence of mesophilic and thermophilic bacteria [J]. Hydrometallurgy, 2008, 93(3, 4): 106-115. DOI: 10.1016/ j.hydromet.2007.11.005.

[137] ZHAO Hong-bo, WANG Jun, GAN Xiao-wen, HU Ming-hao, TAO Lang, QIN Wen-qing, QIU Guan-zhou. Role of pyrite in sulfuric acid leaching of chalcopyrite: An elimination of polysulfide by controlling redox potential [J]. Hydrometallurgy, 2016, 164: 159-165. DOI: 10.1016/ j.hydromet.2016.04.013.

[138] ZHAO Hong-bo, WANG Jun, GAN Xiao-wen, QIN Wen-qing, HU Ming-hao, QIU Guan-zhou. Bioleaching of chalcopyrite and bornite by moderately thermophilic bacteria: An emphasis on their interactions [J]. International Journal of Minerals, Metallurgy, and Materials, 2015, 22(8): 777-787. DOI: 10.1007/s12613-015-1134-7.

[139] BARHOUMI N, OLVERAVARGAS H, OTURAN N, HUGUENOT D, GADRI A, AMMAR S, BRILLAS E, OTURAN M A. Kinetics of oxidative degradation/ mineralization pathways of the antibiotic tetracycline by the novel heterogeneous electro-fenton process with solid catalyst chalcopyrite [J]. Applied Catalysis B-Environmental, 2017, 209: 637-647. DOI: 10.1016/j.apcatb.2017.03.034.

[140] HUANG Xiao-tao, ZHU Tong-he, DUAN Wei-jian, LIANG Sheng, LI Ge, XIAO Wei. Comparative studies on catalytic mechanisms for natural chalcopyrite-induced fenton oxidation: Effect of chalcopyrite type [J]. Journal of Hazardous Materials, 2020, 381: 120998. DOI: 10.1016/ j.jhazmat.2019.120998.

[141] WU Biao, WEN Jian-kang, CHEN Bowei, YAO Guo-cheng, WANG Dian-zuo. Control of redox potential by oxygen limitation in selective bioleaching of chalcocite and pyrite [J]. Rare Metals, 2014, 33(5): 622-627. DOI: 10.1007/s12598- 014-0364-6.

[142] CHANDRA A P, GERSON A R. The mechanisms of pyrite oxidation and leaching: A fundamental perspective [J]. Surface Science Reports, 2010, 65(9): 293-315. DOI: 10.1016/j.surfrep.2010.08.003.

[143] RUITENBERG R, HANSFORD G S, REUTER M A, BREED A W. The ferric leaching kinetics of arsenopyrite [J]. Hydrometallurgy, 1999, 52(1): 37-53. DOI: 10.1016/ S0304-386X(99)00007-9.

[144] MAY N, RALPH D E, HANSFORD G S. Dynamic redox potential measurement for determining the ferric leach kinetics of pyrite [J]. Minerals Engineering, 1997, 10(11): 1279-1290. DOI: 10.1016/S0892-6875(97)00114-3.

[145] NICOL M, MIKI H, BASSON P. The effects of sulphate ions and temperature on the leaching of pyrite. 2. Dissolution rates [J]. Hydrometallurgy, 2013, 133: 182-187. DOI: 10.1016/j.hydromet.2013.01.009.

[146] CHANDRA A P, GERSON A R. Redox potential (E_h) and anion effects of pyrite (FeS₂) leaching at pH 1 [J]. Geochimica et Cosmochimica Acta, 2011, 75(22): 6893- 6911. DOI: 10.1016/j.gca.2011.09.020.

[147] SUN He-yun, CHEN Miao, ZOU Lai-chang, SHU Rong-bo, RUAN Ren-man. Study of the kinetics of pyrite oxidation under controlled redox potential [J]. Hydrometallurgy, 2015, 155: 13-19. DOI: 10.1016/j.hydromet.2015.04.003.

[148] WEI Zhen-lun, LI Yu-biao, GAO Hui-min, ZHU Yang-ge, QIAN Gu-jie, YAO Jun. New insights into the surface relaxation and oxidation of chalcopyrite exposed to O₂ and H₂O: A first-principles DFT study [J]. Applied Surface Science, 2019, 492: 89-98. DOI: 10.1016/j.apsusc.2019.06. 191.

[149] ZHAO Hong-bo, WANG Jun, TAO Lang, CAO Pan, YANG Cong-ren, QIN Wen-qing, QIU Guan-zhou. Roles of oxidants and reductants in bioleaching system of chalcopyrite at normal atmospheric pressure and 45 °C [J]. International Journal of Mineral Processing, 2017, 162: 81-91. DOI: 10.1016/j.minpro.2017.04.002.

[150] WANG Jun, ZHU Shan, ZHANG Yan-sheng, ZHAO Hong-bo, HU Ming-hao, YANG Cong-ren, QIN Wen-qing, QIU Guan-zhou. Bioleaching of low-grade copper sulfide ores by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans [J]. Journal of Central South University, 2014, 21(2): 728-734. DOI: 10.1007/s11771-014-1995-3.

[151] YANG Yi, LIU Wei-hua, BHARGAVA S K, ZENG Wei-min, CHEN Miao. A XANE and XRD study of chalcopyrite bioleaching with pyrite [J]. Minerals Engineering, 2016, 89: 157-162. DOI: 10.1016/j.mineng.2016.01.019.

[152] YANG Y, TAN S N, GLENN A M, HARMER S, BHARGAVA S, CHEN M. A direct observation of bacterial coverage and biofilm formation by Acidithiobacillus ferrooxidans on chalcopyrite and pyrite surfaces [J]. Biofouling, 2015, 31(7): 575-586. DOI: 10.1080/08927014. 2015.1073720.

[153] WU Biao, WEN Jian-kang, CHEN Bo-wei, YAO Guo-cheng, WANG Dian-zuo. Control of redox potential by oxygen limitation in selective bioleaching of chalcocite and pyrite [J]. Rare Metals, 2014, 33(5): 622-627. DOI: 10.1007/s12598- 014-0364-6.

[154] LI Yu-biao, QIAN Gu-jie, BROWN P L, GERSON A R. Chalcopyrite dissolution: Scanning photoelectron microscopy examination of the evolution of sulfur species with and without added iron or pyrite [J]. Geochimica et Cosmochimica Acta, 2017, 212: 33-47. DOI: 10.1016/j.gca. 2017.05.016.

[155] OLVERA O G, QUIROZ L, DIXON D G, ASSELIN E. Electrochemical dissolution of fresh and passivated chalcopyrite electrodes. Effect of pyrite on the reduction of Fe³⁺ ions and transport processes within the passive film [J]. Electrochimica Acta, 2014, 127: 7-19. DOI: 10.1016/ j.electacta.2014.01.165.

[156] RUIZ M C, MONTES K S, PADILLA R. Galvanic effect of pyrite on chalcopyrite leaching in sulfate-chloride media [J]. Mineral Processing and Extractive Metallurgy Review, 2014, 36(1): 65-70. DOI: 10.1080/08827508.2013.868349.

[157] HAN Hai-sheng, SUN Wei, HU Yue-hua, CAO Xue-feng, TANG Hong-hu, LIU Run-qing, YUE Tong. Magnetite precipitation for iron removal from nickel-rich solutions in hydrometallurgy process [J]. Hydrometallurgy, 2016, 165: 318-322. DOI: 10.1016/j.hydromet.2016.01.006.

[158] YUE Tong, HAN Hai-sheng, SUN Wei, HU Yue-hua, CHEN Pan, LIU Run-qing. Low-pH mediated goethite precipitation and nickel loss in nickel hydrometallurgy [J]. Hydrometallurgy, 2016, 165: 238-243. DOI: 10.1016/ j.hydromet.2016.03.004.

[159] HUANG Xiao-tao, ZHAO Hong-bo, ZHANG Yi-sheng, LIAO Rui, WANG Jun, QIN Wen-qing, QIU Guan-zhou. A strategy to accelerate the bioleaching of chalcopyrite through the goethite process [J]. Minerals & Metallurgical Processing, 2018, 35(4): 171-175. DOI: 10.19150/mmp.8593.

(Edited by YANG Hua)

中文导读

氧化还原电位在黄铜矿生物湿法冶金中的作用及其调控：综述

摘要：黄铜矿是一种重要的铜资源，但由于黄铜矿晶格能较高，溶解动力学较低，导致其在湿法冶金过程中浸出效率不理想。为了解决这一问题进行了一系列新技术的研究，包括对高效菌株的选育，抑制在矿物表面钝化膜的生成，以及控制溶液氧化还原电位在最佳区间内。目前，对前两个技术的研究工作已有大量的总结，而对于控制氧化还原电位这一过程的工作总结较少。本文通过研究近年来的相关工作，介绍了铜湿法冶金过程中溶液氧化还原电位的定义、作用以及对氧化还原电位的控制等相关内容。

关键词：黄铜矿；铜矿物；溶液电位；湿法冶金过程

HUANG Xiao-tao and LIAO Rui contributed equally to this work.

Foundation item: Projects(51774332, U1932129, 51804350, 51934009) supported by the National Natural Science Foundation of China; Project(2018JJ1041) supported by the Natural Science Foundation of Hunan Province, China

Received date: 2020-05-04; Accepted date: 2020-05-15

Corresponding author: WANG Jun, PhD, Professor; Tel: +86-731-88876557; E-mail: wjwq2000@126.com; ORCID: 0000-0003-0931- 3946