Method for strengthening chalcopyrite leaching by leptospirillum ferriphilum inducer

Abstract

The invention discloses a method for strengthening chalcopyrite leaching through leptospirillum ferriphilum inducers, and belongs to the technical field of mineral biological leaching. The invention discloses a method for strengthening chalcopyrite leaching through a leptospirillum ferriphilum inducer. The bioleaching process of chalcopyrite is regulated and controlled through the leptospirillum ferriphilum inducer. According to the method for strengthening chalcopyrite leaching through the leptospirillum ferriphilum inducer, through the specific regulation and control effect of the leptospirillum ferriphilum inducer, the metabolic activity and environmental tolerance of microbial communities in the chalcopyrite bioleaching process are improved, and therefore the bioleaching efficiency of chalcopyrite is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of mineral bioleaching, and more particularly to a method for strengthening leaching of chalcopyrite using an inducer of ferrospira leptospira. Background Art

[0002] Chalcopyrite (CuFeS2) is the most abundant copper-containing mineral, accounting for 70% of the known global copper reserves. Compared with traditional pyrometallurgical processes, bioleaching technology is particularly suitable for the treatment of low-grade complex metal minerals, especially chalcopyrite, due to its advantages such as low cost, strong adaptability and environmental friendliness. Bioleaching technology mainly uses the metabolic activities of microorganisms such as iron-oxidizing bacteria to convert metal elements in ores into a dissolved state, thereby achieving metal extraction. However, bioleaching technology depends on the growth and metabolic rate of bacteria and is greatly affected by environmental factors such as temperature, pH value, oxygen concentration, and heavy metal ion concentration. In addition, chalcopyrite has stable chemical properties, and a dense passivation layer will form on the surface during the oxidation process. These problems lead to extremely low bioleaching efficiency of chalcopyrite, which seriously hinders the application of bioleaching technology.

[0003] Improving the leaching rate has always been a difficult problem in chalcopyrite bioleaching technology. Studies have shown that the efficiency of bioleaching can be effectively improved by enhancing the metabolic activity of specific strains or introducing efficient microbial communities. However, the research on microbial enhancement methods in the existing technology is not mature enough, especially how to specifically regulate the structure of metallurgical microbial communities, so that efficient strains dominate the leaching process, and improve the tolerance and activity of the community, which is still a problem to be solved.

[0004] Therefore, providing a method for enhancing chalcopyrite leaching with ferrospira ferrospira inducers is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] In view of this, the present invention provides a method for strengthening the leaching of chalcopyrite by using an inducer of Leptospirillum ferrophilum, and utilizes the inducer of Leptospirillum ferrophilum to specifically regulate the mineral leaching flora, thereby enhancing the biological leaching efficiency of chalcopyrite. The method of the present invention can not only effectively improve the metabolic activity of the flora during the leaching process, but also optimize the structural and functional stability of the flora, thereby realizing the efficient utilization of low-grade chalcopyrite resources, and providing an innovative, efficient, economical and environmentally friendly new technical solution with broad application prospects for industrial metal recovery.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for enhancing chalcopyrite leaching by ferrospira leptospira inducer ( Figure 1 ), the specific steps are as follows:

[0008] (1) Preparation of ferroferrophilic Leptospirillum culture

[0009] Inoculate Leptospirillum ferriphilum into 100 mL of BSM medium and culture until the bacterial concentration is 4.0-20×10 8 cells / mL, to obtain the culture of Leptospirillum ferroferrophilum;

[0010] (2) Preparation of inducers

[0011] Exposing the ferrospira culture obtained in step (1) to a 254 nm ultraviolet radiation source at a distance of 10-30 cm for 5-10 min, transferring the bacterial culture to 37° C. and continuing to incubate for 2-4 hours;

[0012] (3) Inducer enrichment and purification

[0013] A. Centrifuge the mixed culture induced in step (2), remove the bacterial precipitate, collect the supernatant, add 10% (w / v) PEG8000 and 1 mol / L NaCl, fully dissolve, and place in a 4°C refrigerator overnight for sedimentation;

[0014] B. Centrifuge the supernatant after treatment in step A, remove the supernatant, and collect the precipitate;

[0015] C. Resuspend the pellet with 3-5 mL SM buffer, add an equal volume of chloroform and DNase I with a final concentration of 10-20 μg / mL to the resuspended solution, shake for 30-60 seconds to mix thoroughly, and incubate at 37°C for 15-30 minutes;

[0016] D. Centrifuge the liquid treated in step C, collect the upper aqueous phase, obtain the ferrotropic Leptospirillum inducer, and store it in a refrigerator at 4°C;

[0017] (4) Chalcopyrite bioleaching experiment: A chalcopyrite bioleaching experiment was conducted with a slurry concentration of 1%-10% (w / v), a temperature of 30-40°C, a pH of 1.5-3.5, and a dissolved oxygen of 2-8 mg / L. The leaching period was 7-60 days, and the microbial community structure, physical and chemical properties, and mineral morphology of the leaching solution were monitored.

[0018] (5) Regulation of chalcopyrite bioleaching process by ferrospira inducers: When the chalcopyrite bioleaching began to form a passive film 7-12 days after bioleaching, 0.5% (v / v) ferrospira inducers were added;

[0019] (6) Leaching efficiency evaluation: The effect of this method on improving the leaching efficiency of chalcopyrite was evaluated by quantitative analysis of metal ion concentrations, thereby verifying the promoting effect of bacteriophages in the bioleaching process.

[0020] Furthermore, the BSM medium components are as follows: 3.0 g / L (NH4)2SO4, 0.5 g / LMgSO4·7H2O, 0.15 g / LNa2SO4·10H2O, 0.05 g / L KH2PO4, 0.1 g / L KCl and 0.014 g / L Ca(NO3)2·4H2O, the pH is adjusted to 2.0 with 3 mol / L sulfuric acid, sterilized at 121°C for 20 min, and 44.7 g / L FeSO4·7H2O is added for UV sterilization.

[0021] Furthermore, the deposit number of the ferriphilic Leptospirillum ferriphilum is CBCBSUCSU208015, and the strain number is YSK.

[0022] Furthermore, the culture conditions in step (1) are cultured in a shaker at 37° C. and 180 rpm.

[0023] Furthermore, the centrifugation conditions in steps (3) A and B are to place the mixture in a desktop centrifuge and centrifuge it at 9000 rpm for 30 min.

[0024] Furthermore, the centrifugation condition in step (3)D is to place the mixture in a desktop centrifuge at 3000 rpm for 15 minutes.

[0025] The present invention utilizes the specific effect of the ferrospira inducer on the iron-oxidizing microorganisms in the biological leaching system to enhance the biological activity of the strain during the leaching process, specifically regulate the metabolic pathway and flora structure of the mineral leaching flora, slow down the formation of the passivation film, and effectively improve the leaching efficiency of chalcopyrite.

[0026] It can be seen from the above technical scheme that, compared with the prior art, the present invention discloses a method for enhancing leaching of chalcopyrite by using an inducer of Leptospirillum ferrophilum, which improves the metabolic activity and environmental tolerance of the microbial community in the bioleaching process of chalcopyrite through the specific regulatory effect of the inducer of Leptospirillum ferrophilum, thereby significantly improving the bioleaching efficiency of chalcopyrite. It has the following advantages and cumulative effects:

[0027] (1) Significantly improve leaching efficiency: by using ferroferric Leptospirillum inducers to influence the target bacteria, enhance the activity of the target bacteria, significantly increase the metal dissolution release rate, and shorten the leaching time;

[0028] (2) Improvement of bacterial community stability: The dynamic addition of ferroferrophilic Leptospirillum inducers optimizes the synergistic effect of bacterial communities and ensures the stability and sustained activity of the leaching microbial community in extreme environments (such as low pH and high metal ion concentrations);

[0029] (3) Environmentally friendly and low cost: Compared with traditional pyrometallurgy and chemical leaching technology, the present invention achieves efficient treatment of low-grade chalcopyrite resources through the synergistic effect of microorganisms, does not require the addition of a large amount of toxic chemical reagents, reduces environmental pollution, and has a simple process and is economical and efficient;

[0030] (4) Wide applicability: The method of the present invention is not only applicable to chalcopyrite, but can also be extended to the bioleaching of other complex metal minerals, providing a new technical path for the resource utilization of low-grade complex ores;

[0031] (5) Strong innovation: The present invention applies microbial inducer regulation technology to the mineral bioleaching process for the first time, breaking through the limitations of traditional microbial enhancement methods and providing an economical, environmentally friendly and efficient leaching method.

[0032] In summary, the present invention improves the bioleaching efficiency of chalcopyrite through the innovative ferroferrophilic Leptospira inducer enhancement technology, while also achieving a balance between resource utilization and environmental friendliness, and has significant industrial application value and broad promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0034] Figure 1 The accompanying drawing is a flow chart of the method for enhancing chalcopyrite leaching by ferrospira ferrospira inducers of the present invention;

[0035] Figure 2 The accompanying drawing shows the bacterial concentration of the leachate during the biological stirring leaching of chalcopyrite according to the present invention;

[0036] Figure 3 The accompanying figure shows the relative abundance of Leptospira during the biological stirring leaching process of chalcopyrite of the present invention;

[0037] Figure 4 The attached figure is a SEM image of the mineral surface of chalcopyrite on the 15th day of biological agitation leaching of the present invention;

[0038] Among them, a: CK; b: Treat;

[0039] Figure 5 The accompanying drawing shows the leaching rate of copper element on the 30th day of chalcopyrite biological agitation leaching of the present invention;

[0040] Figure 6 The accompanying drawing is a SEM image of the mineral surface on the 33rd day of chalcopyrite bio-heap leaching of the present invention;

[0041] Among them, a: CK; b: Treat;

[0042] Figure 7 The accompanying figure shows the leaching rate of copper element on the 60th day of chalcopyrite bio-heap leaching of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] A method for preparing an inducer of ferrospira leptospira, the specific steps of which are as follows:

[0046] (1) Preparation of ferroferrophilic Leptospirillum culture

[0047] Leptospirillum ferriphilum (Accession No.: CBCBSUCSU208015, strain No.: YSK) was inoculated into 100 mL of BSM medium and cultured in a shaker at 37 °C and 180 rpm until the bacterial concentration reached 4.0 × 10 8 cells / mL, to obtain the culture of Leptospirillum ferroferrophilum;

[0048] The components of BSM medium are as follows: 3.0 g / L (NH4)2SO4, 0.5 g / L MgSO4·7H2O, 0.15 g / L Na2SO4·10H2O, 0.05 g / L KH2PO4, 0.1 g / L KCl and 0.014 g / L Ca(NO3)2·4H2O. The pH was adjusted to 2.0 with 3 mol / L sulfuric acid, sterilized at 121°C for 20 min, and 44.7 g / L FeSO4·7H2O was added for UV sterilization.

[0049] (2) Preparation of inducers

[0050] Exposing the ferrospira culture obtained in step (1) to a 254 nm ultraviolet radiation source at a distance of 30 cm for 10 min, transferring the bacterial culture to 37° C. and continuing to incubate for 4 hours;

[0051] (3) Inducer enrichment and purification

[0052] A. Place the mixed culture induced in step (2) in a desktop centrifuge at 9000 rpm for 30 min, remove the bacterial precipitate, collect the supernatant, add 10% (w / v) PEG8000 and 1 mol / L NaCl, fully dissolve, and place in a 4°C refrigerator overnight for sedimentation;

[0053] B. Centrifuge the supernatant after step A at 9000 rpm in a desktop centrifuge for 30 min, remove the supernatant, and collect the precipitate;

[0054] C. Resuspend the pellet with 5 mL of SM buffer, add an equal volume of chloroform and DNase I (Thermo Scientific DNase I, Catalog No. EN0521) with a final concentration of 20 μg / mL to the resuspended solution, shake for 30 seconds to mix thoroughly, and incubate at 37°C for 30 minutes;

[0055] D. Place the liquid treated in step C in a desktop centrifuge and centrifuge at 3000 rpm for 15 min, collect the upper aqueous phase to obtain the ferroferrophilic Leptospira inducer, and store it in a 4°C refrigerator.

[0056] Collection of leached microbial suspension:

[0057] Acid mine drainage (AMD) from Dabaoshan, Shaoguan City, Guangdong Province was collected and enriched with (1) 9K medium + 44.7 g / L FeSO4·7H2O; (2) 9K medium + 10 g / L sublimed sulfur; (3) 9K medium + 22.4 g / L FeSO4·7H2O + 5 g / L sublimed sulfur + 0.2 g / L yeast extract. The culture was continued for three generations at 30°C, 180 rpm / min, and 48 h. The three groups of cultures of the third generation were evenly mixed at a ratio of 1:1:1 as microbial enrichment (leaching microbial suspension) for subsequent chalcopyrite bioleaching experiments. The initial concentration was about 2.0×10 8 cells / mL.

[0058] The components of 9K medium are as follows: 3.0 g / L (NH4)2SO4, 0.5 g / L MgSO4·7H2O, 0.15 g / L Na2SO4·10H2O, 0.05 g / L KH2PO4, 0.1 g / L KCl and 0.014 g / L Ca(NO3)2·4H2O. The pH is adjusted to 2.0 with 3 mol / L sulfuric acid and sterilized at 121°C for 20 min.

[0059] Chalcopyrite:

[0060] Chalcopyrite was purchased from Shaoguan City, Guangdong Province. ICP analysis results showed that the elemental composition of chalcopyrite samples was mainly iron, sulfur and copper, accounting for 30.7%, 34.3% and 32.7% respectively.

[0061] Example 2

[0062] (1) ball-grind chalcopyrite through a 200-mesh sieve;

[0063] (2) Constructing a 1L chalcopyrite biological stirring leaching system: 10% chalcopyrite and 10% leaching microbial suspension were added to 1L 9K medium and cultured continuously at 30°C and 300 rpm;

[0064] (3) A control group (CK) and a group treated with ferrospira ferrospira inducer (Treat) were set up. No substance was added to the control group, and 1 mL of ferrospira ferrospira inducer was added to the treatment group on the 12th day of leaching. Each group had 5 biological replicates.

[0065] (4) monitor the changes in microbial community structure during the leaching process;

[0066] (5) Observe the surface morphology of the minerals on the 15th day of leaching;

[0067] (6) On the 30th day of leaching, the copper ion concentration of the leachate was detected and the copper leaching rate was calculated.

[0068] The results showed that the treatment with ferrospira inducer significantly increased the bacterial concentration in the leaching solution ( Figure 2 ), especially the relative abundance of Leptospirillum ( Figure 3 ). In addition, the treatment significantly reduced the passive film on the chalcopyrite surface and increased the biofilm coverage ( Figure 4 ). On the 30th day of leaching, the copper leaching rate of the treatment group increased by 78.21% compared with the control group ( Figure 5 ).

[0069] Example 3

[0070] (1) Ball mill the chalcopyrite to 40 mm;

[0071] (2) Construct a chalcopyrite heap leaching test system with a heap area of ​​about 10m 2 , stacked, each layer is about 1m thick, the pile height is 2m, and the stacking density is about 1.4t / m 3 Every 12 days, use a nozzle to evenly spray the leached microbial suspension onto the pile surface, with a spraying volume of about 1L / m 3 .

[0072] (3) A control group (CK) and a treatment group (Treat) containing ferrospira ferrospira inducer were set up. The control group did not add any other substances. The treatment group added 1 L of ferrospira ferrospira inducer per ton of chalcopyrite on the 30th day of leaching and evenly sprayed it on the heap leached ore.

[0073] (4) Detect the copper ion concentration in the leachate on the 60th day and calculate the change in the leaching rate of copper element in chalcopyrite.

[0074] Compared with the control group, the passive film on the chalcopyrite surface in the group treated with the ferrospira inducer was significantly reduced and the corrosion effect was enhanced ( Figure 6 ), which accelerated the leaching process, and by the 60th day, the copper leaching rate increased by 65.50% ( Figure 7 ).

[0075] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for enhancing leaching of chalcopyrite using an inducer of Leptospira ferrophila, characterized in that: The specific steps are as follows: (1) Preparation of ferroferrophilic Leptospirillum culture Inoculate 100 mL of BSM medium with Leptospirillum ferriphilum and culture until the bacterial concentration is 4.0-20×10 8 cells / mL, to obtain the culture of Leptospirillum ferroferrophilum; (2) Preparation of inducers Exposing the ferrospira culture obtained in step (1) to a 254 nm ultraviolet radiation source at a distance of 10-30 cm for 5-10 min, transferring the bacterial culture to 37° C. and continuing to incubate for 2-4 hours; (3) Inducer enrichment and purification A. Centrifuge the mixed culture induced in step (2), remove the bacterial precipitate, collect the supernatant, add 10% (w / v) PEG8000 and 1 mol / L NaCl, fully dissolve, and place in a 4°C refrigerator overnight for sedimentation; B. Centrifuge the supernatant after treatment in step A, remove the supernatant, and collect the precipitate; C. Resuspend the pellet with 3-5 mL SM buffer, add an equal volume of chloroform and DNase I with a final concentration of 10-20 μg / mL to the resuspended solution, shake for 30-60 seconds to mix thoroughly, and incubate at 37°C for 15-30 minutes; D. Centrifuge the liquid treated in step C, collect the upper aqueous phase, obtain the ferrotropic Leptospirillum inducer, and store it in a refrigerator at 4°C; (4) Regulation of chalcopyrite bioleaching process by ferrospira inducers: When the chalcopyrite bioleaching began to form a passive film 7-12 days after bioleaching, 0.5% (v / v) ferrospira inducers were added.

2. The method for enhancing chalcopyrite leaching by using an inducer of Leptospira ferroferrophila according to claim 1, characterized in that: The components of the BSM culture medium are as follows: 3.0 g / L (NH4)2SO4, 0.5 g / LMgSO4·7H2O, 0.15 g / L Na2SO4·10H2O, 0.05 g / L KH2PO4, 0.1 g / L KCl and 0.014 g / L Ca(NO3)2·4H2O, the pH is adjusted to 2.0 with 3 mol / L sulfuric acid, sterilized at 121°C for 20 min, and 44.7 g / L FeSO4·7H2O is added for UV sterilization.

3. The method for enhancing chalcopyrite leaching by using an inducer of Leptospira ferroferrophila according to claim 1, characterized in that: The deposit number of the ferrophilic Leptospirillum ferriphilum is CBCBSUCSU208015, and the strain number is YSK.

4. The method for enhancing chalcopyrite leaching by using an inducer of Leptospira ferroferrophila according to claim 1, characterized in that: The culture conditions of step (1) are to culture in a shaker at 37°C and 180 rpm.

5. The method for enhancing chalcopyrite leaching by using an inducer of Leptospira ferroferrophila according to claim 1, characterized in that: The centrifugation conditions in step (3) A and B are to centrifuge at 9000 rpm for 30 min in a desktop centrifuge.

6. The method for enhancing chalcopyrite leaching by using an inducer of Leptospira ferroferrophila according to claim 1, characterized in that: The centrifugation condition in step (3)D is to place the mixture in a desktop centrifuge and centrifuge it at 3000 rpm for 15 min.

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