Method for promoting bioleaching of chalcopyrite through in-situ depassivation

Abstract

The invention belongs to the field of resources and environments, and discloses a method for promoting bioleaching of chalcopyrite through in-situ depassivation, which comprises the following steps: in an anaerobic environment, adding passivated chalcopyrite and reduced sulfur into a 9K culture medium, inoculating an acidophilic microbial strain for culturing, and centrifugally collecting the chalcopyrite; the collected chalcopyrite is dried and then added into a 9K culture medium, and acidophilic microbial strains are inoculated in an aerobic environment for culture and leaching. According to the method, acidophilic microorganisms and sulfur elements are introduced into an anaerobic system, so that a compact passive film of the chalcopyrite can be reduced and removed, copper ions in minerals are leached under the later aerobic condition, and the defects that pure chemical reaction mineral leaching is large in energy consumption and material consumption and pollutes the environment are overcome; and the problem that the utilization efficiency is low due to the fact that leaching is hindered by a passive film in the bioleaching process is solved, and the chalcopyrite can be utilized to the maximum extent. The in-situ depassivation bioleaching technology is extremely wide in application range, low in site requirement and capable of achieving large-scale industrial application.

Description

Technical Field

[0001] The invention belongs to the field of resources and environment, and in particular relates to a method for promoting chalcopyrite bioleaching by in-situ depassivation. Background Art

[0002] my country is rich in chalcopyrite resources (CuFeS2), but small and medium-sized low-grade mineral resources dominate. Previous pyrometallurgical technology has significant pollution problems, huge reagent consumption, and relatively high energy consumption. Therefore, bioleaching technology for low-grade minerals has gradually become a research hotspot with advantages such as simple process operation, low energy consumption, low cost, and environmental friendliness. Bioleaching achieves the dissolution of valuable metals through the interaction between acidophilic microorganisms and minerals. Acidophilic microorganisms use minerals as energy materials through three pathways: direct, indirect, and combined, to achieve oxidative decomposition of sulfide ores and finally obtain copper products. Therefore, enhancing the interaction between bacteria and minerals is an important way to improve the bioleaching rate of chalcopyrite.

[0003] Researchers have used a variety of methods to directly or indirectly improve the efficiency of bacterial-mineral interaction in the chalcopyrite bioleaching system. The current mainstream methods are as follows: adding associated minerals during leaching, or using the ions dissolved from the minerals themselves to affect the redox potential of the system; improving the galvanic cell effect between minerals; optimizing the structure of the acidophilic microbial community - based on the oxidation capacity of different strains, screening and compounding a high leaching rate bacterial community. What cannot be ignored is that there is a bottleneck problem in the use of microbial leaching - the phenomenon of passivation occurs during the leaching process, resulting in a low leaching rate, which has always limited the application and development of bacterial copper leaching. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a method for promoting chalcopyrite bioleaching by in-situ depassivation.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for promoting chalcopyrite bioleaching by in-situ depassivation comprises the following steps: (1) In an anaerobic environment, passivated chalcopyrite and reduced sulfur were added to 9K culture medium, acidophilic microbial strains were inoculated for cultivation, and chalcopyrite was collected by centrifugation; (2) The collected chalcopyrite is dried and added to 9K culture medium, inoculated with acidophilic microbial strains in an aerobic environment, cultured and leached.

[0006] In the above-mentioned in-situ depassivation method for promoting chalcopyrite bioleaching, preferably, in step (1), the amount of passivated chalcopyrite added is 1wt%-20wt% of the culture medium, the reduced sulfur is calculated as elemental sulfur, and the elemental sulfur is added to make its concentration in the culture medium reach 0.5g-10g / L; the inoculation amount of the acidophilic microbial strain is 1.0×10 6 -1×10 9 Pieces / mL.

[0007] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (1), the initial pH of the 9K culture medium is 1.5-3.0, the culture temperature is 25-35°C, the shaking speed during the culture process is 100-250 rpm, and the culture time is 6-25 days.

[0008] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (1), when the concentration of copper ions in the culture medium is measured to reach 800-1200 mg / L, the culture is stopped.

[0009] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (1), the reduced sulfur is at least one of elemental sulfur, sodium sulfide, sodium sulfite, and sodium thiosulfate; The acidophilic microbial strain is selected from Thiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) , Leptospirillum ferrooxidans (Leptospirillum ferrooxidans) , Leptospirillum ferroferrophilum (Leptospirillum ferriphilum) , Thiobacillus thiooxidans (Acidithiobacillus thiooxidans) , Bacillus thermooxidans (Sulfobacillus thermosulfidooxidans) Acidithiobacillus (Acidithiobacillus caldus) Sulfolobus metallifolius (sulfolobus metallicus) One of them.

[0010] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (1), during the cultivation process, a non-oxygen stable gas is regularly added to the anaerobic environment system to maintain the anaerobic environment.

[0011] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (2), the initial pH of the 9K culture medium is 1.5-3.0, the culture temperature is 25-35°C, the shaking speed during the culture process is 100-250 rpm, and the culture time is 5-25 days.

[0012] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (2), the amount of chalcopyrite collected is 1wt%-20wt% of the culture medium; the inoculation amount of the acidophilic microbial strain is 1×10 6 -1×10 9 Pieces / mL.

[0013] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (1), the acidophilic microbial strain is first cultured to a logarithmic growth phase and then collected and added to an anaerobic environment.

[0014] In the above-mentioned method for promoting chalcopyrite bioleaching by in-situ depassivation, preferably, in step (2), the aerobic environment refers to an oxygen concentration not lower than the oxygen concentration in the atmosphere.

[0015] The surface passivation of chalcopyrite contains substances such as jarosite, elemental sulfur, and polysulfide. The generation of mineral surface passivation during the leaching process is a key factor in inhibiting the bioleaching rate. The present invention adjusts the dissolved oxygen concentration in the chalcopyrite bioleaching system with a low copper leaching rate, and after switching to anaerobic conditions, adds low-valent sulfur substances to the system. Under this condition, the large iron-sulfur oxidation function of the acidophilic leaching microorganisms is converted into iron reduction and sulfur oxidation functions, and the Fe in the mineral surface passivation is reduced. 3+ Reduction to Fe 2 + , dissolving and destroying the passivation film, the depassivated chalcopyrite is returned to the leaching stage in an aerobic environment, and efficient copper leaching can be achieved again.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention introduces acidophilic microorganisms and sulfur elements into the anaerobic system, so that the dense passivation film of chalcopyrite can be reduced and removed, so that the copper ions in the mineral continue to be leached under aerobic conditions in the later stage, which not only overcomes the shortcomings of pure chemical reaction leaching, such as high energy consumption, large consumables, and environmental pollution, but also solves the problem of low utilization efficiency due to the passivation film hindering leaching in the biological leaching process, so that chalcopyrite can be utilized to the greatest extent. The in-situ depassivation biological leaching technology has a very wide range of application, low site requirements, and can be used on a large scale in an industrialized manner.

[0017] In summary, the present invention regulates the key metabolic pathways such as Fe / S / Cu in the bacteria-mineral interaction system by controlling the dissolved oxygen content in the leaching system, thereby affecting the growth and ablation process of the passivation layer on the mineral surface, and utilizes anaerobic iron-reducing acidophilic microorganisms to achieve in-situ removal of the passivation layer on the mineral surface during chalcopyrite bioleaching, providing new ideas for the development of low-cost, pollution-free copper leaching enhancement technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 EDS surface scans of passivated chalcopyrite used in the embodiments of the present invention: a is an image of passivated chalcopyrite, b is a surface scan of the O element of the passivated chalcopyrite, c is a surface scan of the K element of the passivated chalcopyrite, d is a surface scan of the S element of the passivated chalcopyrite, e is a surface scan of the Fe element of the passivated chalcopyrite, and f is a surface scan of the Cu element of the passivated chalcopyrite.

[0019] Figure 2 This is a diagram of the generation of ferrous ions in the depassivation experimental system using elemental sulfur in Example 1 of the present invention.

[0020] Figure 3 This is a diagram of ferrous ion generation in the sodium thiosulfate depassivation experimental system in Example 2 of the present invention.

[0021] Figure 4 This is a diagram of ferrous ion generation in the sodium thiosulfate depassivation experimental system in Example 3 of the present invention.

[0022] Figure 5 This is a comparison chart of leaching of passivated copper ore and leaching of depassivated copper in Example 1 of the present invention.

[0023] Figure 6 This is a comparison chart of passivated copper leaching and depassivated copper leaching in Example 2 of the present invention.

[0024] Figure 7 It is the potassium ion concentration in the system during the anaerobic experiment in Example 2 of the present invention.

[0025] Figure 8 These are three ion concentrations at different stages in Example 2 of the present invention: A is the first stage passivation experiment, B is the second stage anaerobic depassivation experiment, and C is the third stage aerobic bioleaching experiment. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0027] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0029] The EDS scans of the passivated chalcopyrite used in Examples 1, 2, and 3 below are shown in Figure 1 As shown in the figure, it can be seen that there is a layer on the surface of chalcopyrite that is rich in K, O, and S elements, namely the passivation layer jarosite.

[0030] Embodiment 1: A method for promoting chalcopyrite bioleaching by in-situ depassivation comprises the following steps: (1) Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans)Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) The culture was expanded in 9K medium, with an initial pH of 2.0, a culture temperature of 30°C, and a shaker speed of 170 rpm. The culture was filtered to separate the solid and liquid when the culture reached the logarithmic phase, and the bacterial liquid was collected by centrifugation at a speed of 9000 rpm for 20 min. (2) Chalcopyrite biopassivation experiment: The experiment was carried out in a 500 mL conical flask containing 198 mL of sterile deionized water, 2 mL of concentrated Acidithiobacillus ferrooxidans culture without metabolites, and 4 g of chalcopyrite sample. The initial pH was adjusted to 2.0 with 0.1 mol / L sulfuric acid, and the initial bacterial concentration was 4 × 10 8 / mL. To promote surface passivation, i.e. the formation of jarosite (KFe3(SO4)2(OH)6), 2.224g FeSO4·7H2O and 0.23g K2SO4 were added according to the ratio of iron and potassium in jarosite. The incubation temperature was 30℃, the shaker speed was 170rpm, and the incubation was carried out for 3 days. The passivated chalcopyrite was collected by wet sieving and dried in a vacuum drying oven.

[0031] (3) Anaerobic experiment: Prepare an anaerobic bottle, fill it with 100 mL of 9K medium, add passivated chalcopyrite and S powder, and inoculate the Acidithiobacillus ferrooxidans cultured in step (1). (Acidithiobacillus ferrooxidans) The inoculum size was 4×10 8 / mL, where the concentration of passivated chalcopyrite is 1wt%, the amount of S powder added is 0.2g, that is, the sulfur concentration in the culture medium is 2 g / L; N2 / CO2 gas is regularly added to the system during the anaerobic process to maintain the anaerobic environment, and the culture is carried out for 25 days; the content of copper ions, ferrous ions, and total iron is monitored every 24h. The results of ion parameter monitoring are shown in Tables 1-3, and the results of ferrous ion generation are shown in Figure 2 As shown, Tables 1 to 3 are the ion parameters in the liquid measured by three parallel groups. Under anaerobic conditions, Acidithiobacillus ferrooxidans reduces the ferric iron in jarosite to ferrous iron using elemental sulfur as an electron donor, so the concentration of ferrous iron increases gradually with time; jarosite gradually dissolves with time, and the solid iron in it is converted into ferrous iron ions, so the total iron concentration in the solution also increases with time; when the jarosite passivation layer gradually dissolves, chalcopyrite is exposed, and the microorganisms continue to react with chalcopyrite to dissolve metallic copper, so the concentration of copper ions also gradually increases. Figure 2 What is shown is the change in the concentration of ferrous ions in the anaerobic system solution over time, which shows a trend of continuous increase, indicating that the jarosite on the surface of chalcopyrite gradually dissolves, and the trivalent iron in the jarosite is reduced to ferrous ions and enters the solution.

[0032] Table 1 Ferrous iron concentration in the system (mg / L)

[0033] Table 2 Total iron concentration in the system (mg / L)

[0034] Table 3 Copper ion concentration in the system (mg / L)

[0035] (4) Collecting chalcopyrite after the passivation layer is ablated: When the concentration of copper ions in the culture medium is measured to reach 250 mg / L, collect the chalcopyrite by centrifugation and place it in a vacuum freeze drying oven for drying.

[0036] (5) Aerobic leaching of the passivation group: The passivated chalcopyrite collected after drying in step (2) was added to 100 mL of 9K medium at a concentration of 1 wt %, the leaching gas environment was atmospheric environment, and Acidithiobacillus ferrooxidans was inoculated. (Acidithiobacillus ferrooxidans) The inoculum size was 4×10 7 / mL, the initial pH of 9K medium was 2.0, the culture temperature was 30°C, the shaker speed was 170 rpm, and the culture was carried out for 25 days. Samples were taken every three days to measure the copper ion concentration.

[0037] Aerobic leaching of the depassivation group: The depassivated chalcopyrite collected after drying in step (4) was added to 100 mL of 9K medium at a concentration of 1 wt %, the leaching gas environment was atmospheric environment, and Acidithiobacillus ferrooxidans was inoculated. (Acidithiobacillus ferrooxidans) The inoculum size was 4×10 7 / mL, the initial pH of 9K culture medium was 2.0, the culture temperature was 30℃, the shaking speed was 170rpm, and samples were taken every three days to determine the copper ion concentration. After 15 days of culture, the copper ion concentration increased significantly. The copper ion monitoring data are shown in Table 4. Because the passivation layer formed on the surface of chalcopyrite in the passivation group hindered the leaching of copper, the copper ion leaching of the three parallel groups of the passivation group was very slow and the leaching rate was very low. In the depassivation group, the leaching rate gradually increased with time, and the leaching rate was 6 times that of the passivated chalcopyrite, indicating that the passivation layer on the surface of chalcopyrite gradually melted away.

[0038] The comparison of passivated copper leaching and depassivated copper leaching is shown in the figure below. Figure 5 As shown, the copper ion concentration curve of the passivation group is flat, without significant improvement, while the copper ion concentration curve of the depassivation group shows an upward trend, reaching the highest leaching rate at about 15 days.

[0039] Table 4 Copper ion leaching concentration of passivated ore and depassivated ore in aerobic experiment

[0040] Embodiment 2: A method for promoting chalcopyrite bioleaching by in-situ depassivation comprises the following steps: (1) Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) The culture was expanded in 9K medium, with an initial pH of 2.0, a culture temperature of 30°C, and a shaker speed of 170 rpm. The culture was filtered to separate the solid and liquid when the culture reached the logarithmic phase, and the bacterial liquid was collected by centrifugation at a speed of 9000 rpm for 20 min. (2) Chalcopyrite biopassivation experiment: The experiment was carried out in a 500 mL conical flask containing 198 mL of sterile deionized water, 2 mL of concentrated Acidithiobacillus ferrooxidans culture without metabolites, and 4 g of chalcopyrite sample. The initial pH was adjusted to 2.0 with 0.1 mol / L sulfuric acid, and the initial bacterial concentration was 4 × 10 8 To promote the formation of jarosite (KFe3(SO4)2(OH)6), 2.224g FeSO4·7H2O and 0.23g K2SO4 were added according to the ratio of iron and potassium in jarosite. The culture temperature was 30℃, the shaking speed was 170rpm, and the culture was carried out for 3 days. The passivated chalcopyrite was collected by wet sieving and dried in a vacuum drying oven.

[0041] (3) Anaerobic experiment: Prepare an anaerobic bottle, fill it with 100 mL of 9K medium, add passivated chalcopyrite and Na2SO3, and inoculate the Acidithiobacillus ferrooxidans cultured in step (1). (Acidithiobacillus ferrooxidans) The inoculum size was 4×10 8 / mL, where the concentration of chalcopyrite is 1wt%, the dosage of Na2SO3 is 0.7875g, and N2 / CO2 gas is regularly added to the system during the anaerobic process to maintain the anaerobic environment. The culture is carried out for 25 days; the content of copper ions, ferrous ions, and total iron is monitored every 24h. The results of ion parameter monitoring are shown in Tables 5-7, and the results of ferrous ion generation are shown in Figure 3 As shown. Tables 5 to 7 are the ion parameters in the liquid measured by three parallel groups. Under anaerobic conditions, Acidithiobacillus ferrooxidans uses Na2SO3 as an electron donor to reduce the ferric iron in jarosite to ferrous iron, so the concentration of ferrous iron increases gradually with time. Jarosite gradually dissolves over time, and the solid iron in it is converted into ferrous ions, so the total iron concentration in the solution also increases with time. When the jarosite passivation layer gradually dissolves, chalcopyrite is exposed, and the microorganisms continue to react with chalcopyrite to dissolve metallic copper, so the concentration of copper ions also gradually increases. Figure 3 What is shown is the change in the concentration of ferrous ions in the anaerobic system solution over time, which shows a trend of continuous increase, indicating that the jarosite on the surface of chalcopyrite gradually dissolves, and the trivalent iron in the jarosite is reduced to ferrous ions and enters the solution.

[0042] Table 5 Ferrous iron concentration in the system (mg / L)

[0043] Table 6 Total iron concentration in the system (mg / L)

[0044] Table 7 Copper ion concentration in the system (mg / L)

[0045] (4) Collecting chalcopyrite after the passivation layer is ablated: When the concentration of copper ions in the culture medium is measured to reach 250 mg / L, collect the chalcopyrite by centrifugation and place it in a vacuum freeze drying oven for drying.

[0046] (5) Aerobic leaching of the passivation group: The passivated chalcopyrite collected after drying in step (2) was added to 300 mL of 9K medium at a concentration of 1 wt %, the leaching gas environment was atmospheric environment, and the Acidithiobacillus ferrooxidans was inoculated. (Acidithiobacillus Ferrooxidans) The inoculum size was 4×10 8 The initial pH of the 9K medium was 2.0, the culture temperature was 30°C, the shaker speed was 170 rpm, and the culture was carried out for 25 days. Samples were taken every three days to determine the copper ion concentration.

[0047] Aerobic leaching of the depassivation group: the chalcopyrite collected after drying in step (4) was added to 300 mL of 9K medium at a concentration of 1 wt %, the leaching gas environment was atmospheric environment, and the Acidithiobacillus ferrooxidans was inoculated. (Acidithiobacillus Ferrooxidans) The inoculum size was 4×10 8 The initial pH of the 9K medium was 2.0, the culture temperature was 30°C, and the shaking speed was 170 rpm. After 15 days of culture, the copper ion concentration increased significantly, as shown in Table 8.

[0048] Table 8 Copper ion leaching concentration

[0049] In this example, the leaching of passivated copper ore and the leaching of depassivated copper are compared. Figure 6 As shown, compared with the passivation ore copper leaching, the depassivation copper leaching effect is more significant and can increase the copper leaching efficiency by 25%.

[0050] Figure 7 This is the potassium ion concentration in the system detected by the solution every three days in the anaerobic experiment of this embodiment. The dissolution rate of jarosite can reach 80.12%.

[0051] Figure 8are three key ions (Cu 2+ , Fe 2+ 、SO4 2- ) concentration test results, the first stage of the passivation experiment (the concentration of dissolved oxygen is 3-9mg / L) SO4 2- Continuously reducing, and SO4 2- Participating in the synthesis of jarosite, the second stage of anaerobic depassivation test (dissolved oxygen concentration is 0.1-0.3mg / L) SO4 2- As time goes by, the amount of jarosite on the surface of chalcopyrite gradually increases, corresponding to the dissolution of jarosite on the surface of chalcopyrite, which releases sulfate into the solution and passivates the initial SO4 2- The concentration is almost the same as the SO4 released at the end of anaerobic 2- The concentration remains constant, proving that jarosite is almost completely dissolved. 2+ and Fe 2+ In the first two stages of the experimental system, the concentration was low, and in the third stage, the aerobic bioleaching (the concentration of dissolved oxygen was 3-9 mg / L) increased significantly, indicating that the leaching rate was improved. 2- In the first stage of the passivation experiment, the concentration of SO4 gradually decreased because it participated in the synthesis of the chalcopyrite surface passivation layer. In the second stage of the anaerobic depassivation experiment, the chalcopyrite surface passivation layer gradually dissolved, so SO4 2- The concentration gradually increases. In the third stage of aerobic bioleaching, the negative divalent sulfur in chalcopyrite will be oxidized into SO4 during the bioleaching process of chalcopyrite. 2- , so the concentration gradually increases. It can be seen from the figure that compared with the passivation stage and the depassivation stage, the Cu 2+ Concentration and Fe 2+ The substantial increase in concentration proves that the leaching rate of chalcopyrite has been significantly enhanced.

[0052] Embodiment 3: A method for promoting chalcopyrite bioleaching by in-situ depassivation comprises the following steps: (1) Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) The culture was expanded in 9K medium, with an initial pH of 2.0, a culture temperature of 30°C, and a shaker speed of 170 rpm. The culture was filtered to separate the solid and liquid when the culture reached the logarithmic phase, and the bacterial liquid was collected by centrifugation at a speed of 9000 rpm for 20 min. (2) Chalcopyrite biopassivation experiment: The experiment was carried out in a 500 mL conical flask containing 198 mL of sterile deionized water, 2 mL of concentrated Acidithiobacillus ferrooxidans culture without metabolites, and 4 g of chalcopyrite sample. The initial pH was adjusted to 2.0 with 0.1 mol / L sulfuric acid, and the initial bacterial concentration was 4 × 10 8 To promote the formation of jarosite (KFe3(SO4)2(OH)6), 2.224g FeSO4·7H2O and 0.23g K2SO4 were added according to the ratio of iron and potassium in jarosite. The culture temperature was 30℃, the shaking speed was 170rpm, and the culture was carried out for 3 days. The passivated chalcopyrite was collected by wet sieving and dried in a vacuum drying oven.

[0053] (3) Anaerobic experiment: Prepare an anaerobic bottle, fill it with 100 mL of 9K medium, add passivated chalcopyrite and Na2SO3, and inoculate the Acidithiobacillus ferrooxidans cultured in step (1). (Acidithiobacillus ferrooxidans) The inoculum size was 4×10 8 / mL, where the concentration of passivated chalcopyrite is 1wt%, and the dosage of Na2S2O3 is 0.4938g; N2 / CO2 gas is regularly added to the system during the anaerobic process to maintain the anaerobic environment, and the culture is carried out for 25 days; the content of copper ions, ferrous ions, and total iron is monitored every 24 hours. The results of ion parameter monitoring are shown in Tables 9-11, and the results of ferrous ion generation are shown in Figure 4 As shown. Tables 9 to 11 are the ion parameters in the liquid measured by three parallel groups. Under anaerobic conditions, Acidithiobacillus ferrooxidans uses Na2S2O3 as an electron donor to reduce the ferric iron in jarosite to ferrous iron, so the concentration of ferrous iron increases gradually with time. Jarosite gradually dissolves over time, and the solid iron in it is converted into ferrous ions, so the total iron concentration in the solution also increases with time. When the jarosite passivation layer gradually dissolves, chalcopyrite is exposed, and the microorganisms continue to react with chalcopyrite to dissolve metallic copper, so the concentration of copper ions also gradually increases. Figure 4 What is shown is the change in the concentration of ferrous ions in the anaerobic system solution over time, which shows a trend of continuous increase, indicating that the jarosite on the surface of chalcopyrite gradually dissolves, and the trivalent iron in the jarosite is reduced to ferrous ions and enters the solution.

[0054] Table 9 Ferrous iron concentration in the system (mg / L)

[0055] Table 10 Total iron concentration in the system (mg / L)

[0056] Table 11 Copper concentration in the system (mg / L)

[0057] (4) Collecting chalcopyrite after the passivation layer is ablated: When the concentration of copper ions in the system is measured to reach 250 mg / L, collect the chalcopyrite by centrifugation and place it in a vacuum freeze drying oven for drying.

[0058] (5) Aerobic leaching: The chalcopyrite collected after drying in step (4) was added to 100 mL of 9K medium at a concentration of 1 wt %, the leaching gas environment was atmospheric environment, and the chalcopyrite was inoculated with Acidithiobacillus ferrooxidans. (Acidithiobacillus ferrooxidans) The inoculum size was 4×10 7 / mL, the initial pH of 9K medium was 2.0, the culture temperature was 30°C, the shaker speed was 170rpm, and after 15 days of culture, the copper ion concentration increased significantly, as shown in Table 12.

[0059] Table 12 Copper ion leaching concentration

[0060] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for promoting chalcopyrite bioleaching by in-situ depassivation, characterized in that: The following steps are involved: (1) In an anaerobic environment, passivated chalcopyrite and reduced sulfur were added to 9K culture medium, acidophilic microbial strains were inoculated for cultivation, and chalcopyrite was collected by centrifugation; (2) The collected chalcopyrite is dried and added to 9K culture medium, inoculated with acidophilic microbial strains in an aerobic environment, cultured and leached.

2. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (1), the amount of passivated chalcopyrite added is 1wt%-20wt% of the culture medium, and the reduced sulfur is calculated as elemental sulfur, and the elemental sulfur is added to make its concentration in the culture medium reach 0.5g-10g / L; the inoculation amount of the acidophilic microbial strain is 1.0×10 6 -1×10 9 Pieces / mL.

3. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (1), the initial pH of the 9K culture medium is 1.5-3.0, the culture temperature is 25-35°C, the shaking speed during the culture process is 100-250 rpm, and the culture time is 6-25 days.

4. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (1), when the concentration of copper ions in the culture medium is measured to be 800-1200 mg / L, the culture is stopped.

5. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (1), the reduced sulfur is at least one of elemental sulfur, sodium sulfide, sodium sulfite, and sodium thiosulfate; The acidophilic microbial strain is selected from Thiobacillus ferrooxidans (Acidithiobacillus ferrooxidans) , Leptospirillum ferrooxidans (Leptospirillumferrooxidans) , Leptospirillum ferroferrophilum (Leptospirillum ferriphilum) , Thiobacillus thiooxidans (Acidithiobacillusthiooxidans) , Bacillus thermooxidans (Sulfobacillus thermosulfidooxidans) Acidithiobacillus (Acidithiobacillus caldus Sulfolobus metallifolius (sulfolobus metallicus) One of them.

6. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (1), during the culture process, a non-oxygen stable gas is regularly added to the anaerobic environment system to maintain the anaerobic environment.

7. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (2), the initial pH of the 9K culture medium is 1.5-3.0, the culture temperature is 25-35°C, the shaking speed during the culture is 100-250 rpm, and the culture time is 5-25 days.

8. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (2), the amount of the collected chalcopyrite added is 1wt%-20wt% of the culture medium; the inoculation amount of the acidophilic microbial strain is 1×10 6 -1×10 9 Pieces / mL.

9. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (1), the acidophilic microbial strain is first cultured to a logarithmic growth phase and then harvested and added to an anaerobic environment.

10. The method for promoting chalcopyrite bioleaching by in-situ depassivation according to claim 1, characterized in that: In step (2), the aerobic environment refers to an oxygen concentration not lower than the oxygen concentration in the atmosphere.

Images