Method for treating heap leaching cyanide tailings of gold mine, composite bacterial flora, bacterial agent and preparation thereof

Abstract

The present invention provides a method for treating heap leaching cyanide tailings of gold mines, a composite bacterial community, a bacterial agent and a preparation method. The composite bacterial community comprises a TDB-1 strain, a TCD-1 strain and a Z-90 strain, wherein the TDB-1 strain is a Pseudomonas putida strain, and the deposit number is CGMCC No.21602. The TCD-1 strain is a Methylorubrum pseudosasae, and the deposit number is CGMCC NO.24728. The Z-90 strain is a Burkholderia sp., and the deposit number is CGMCC No.9970. The above-mentioned composite bacterial community can effectively remove cyanide, thiocyanide and metal-cyanide complexes. The present method has the advantages of simple operation, high reduction efficiency, stable effect, good impact resistance and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of environmental microorganisms, and in particular to a method for treating heap leaching cyanide tailings of gold mines, a composite bacterial community, a bacterial agent and their preparation. Background Art

[0002] At present, the gold extraction technology is developing rapidly, and many new processes and methods have emerged, but most of them have high production costs, and industrial applications still need further research and development, which makes it difficult to promote and apply them quickly. At present, 90% of the world's gold production is obtained by cyanidation gold extraction technology, and heap leaching cyanidation tailings are the main solid waste of the cyanidation leaching process of gold mines. Actual production shows that most of the cyanide in the cyanidation leaching process remains in the tailings and in the form of free cyanide, thiocyanate and metal-cyanide complexes, and a small amount volatilizes into the air in the form of HCN (mainly exists as CN- under high alkaline conditions), and the amount used for gold leaching accounts for only about 2% of the total cyaniding agent. Since the cyanidation method uses highly toxic cyanide to extract gold, it brings great challenges to the production and safety of enterprises. With the increasingly stringent national environmental protection policies, the treatment of cyanidation tailings in gold mine yards is imminent. If this problem can be solved well, it will be of great significance to the development of my country's gold production enterprises and environmental protection development.

[0003] The existing methods for repairing cyanide tailings, such as alkaline chlorination, Inco method, ozone oxidation method, etc., all have certain shortcomings. Alkaline chlorination is a relatively mature method for destroying cyanide in wastewater and is currently the most commonly used cyanide treatment method. However, the pH value of this method has a great influence on the oxidation reaction, and the treatment effect on ferrocyanide complex is not good. Inco method is also known as sulfur dioxide-air method, which can make cyanide (CN － ) is oxidized into carbon dioxide (CO2) and ammonia (NH3). This method can not only oxidize and decompose free cyanide and weakly complexed cyanide, but also treat ferrocyanide and ferrocyanide with strong binding force. However, it cannot treat SCN in cyanide-containing wastewater. － The disadvantages of ozone oxidation are large dosage of reagents, large power consumption of ozone generator, harsh reaction conditions and low ozone utilization rate. In addition, ozone has no oxidation ability for cyanide in iron and ferrocyanide, and can only oxidize Fe(CN)6 4- Oxidized to Fe(CN)6 3- Therefore, when the wastewater contains Fe(CN)6 4- When the ozone oxidation method is used, the effect is not ideal.

[0004] In comparison, the microbial method for treating pollution in the cyanide heap leaching process is economical, efficient, clean, and has great development potential. However, the strong specificity of microorganisms and the single function of single strains are not suitable for complex contaminated sites. It is aimed at the complex pollution control problems of residual cyanide leaching agents and heavy metal cyanide complexes (Pb, Cu, As, Zn, etc.) in gold mine heap leaching sites. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for treating heap leaching cyanide tailings of gold mines, a composite bacterial community, a bacterial agent and preparation, so as to solve the technical problem that the function of a single bacterial strain is not suitable for treating heap leaching cyanide tailings in a gold mine heap leaching site.

[0006] To achieve the above object, the present invention provides a composite bacterial community for treating heap leaching cyanide tailings of gold mines in a first aspect, wherein the composite bacterial community comprises TDB-1 strain, TCD-1 strain and Z-90 strain, wherein TDB-1 strain is Pseudomonas putida Pseudomonas putida strain The deposit number is CGMCC No. 21602. TCD-1 strain is Pseudomonas methylotrophicus Methylorubrum pseudosasae , the deposit number is CGMCC NO. 24728. Z-90 strain is Burkholderia Burkholderia sp. , the deposit number is CGMCC No.9970.

[0007] The second aspect of the present invention provides a composite bacterial agent for treating heap leaching cyanide tailings of gold mines, comprising a culture medium and TDB-1 strain, TCD-1 strain and Z-90 strain dispersed in the culture medium. The TDB-1 strain is Pseudomonas putida Pseudomonas putida strain The deposit number is CGMCC No. 21602. TCD-1 strain is Pseudomonas methylotrophicus Methylorubrum pseudosasae , the deposit number is CGMCC NO. 24728. Z-90 strain is Burkholderia Burkholderia sp. , the deposit number is CGMCC No.9970.

[0008] According to an embodiment of the present application, the culture medium is LB liquid culture medium.

[0009] The third aspect of the present invention provides a method for preparing a composite bacterial agent for treating heap leaching cyanide tailings of gold mines, comprising:

[0010] The first bacterial liquid of the TDB-1 strain, the second bacterial liquid of the TCD-1 strain and the third bacterial liquid of the Z-90 strain were added to the culture medium for expansion culture, and cultured at pH 9 and 30±2° C. for at least 2 days to obtain a composite bacterial agent.

[0011] Among them, the TDB-1 strain is Pseudomonas putida Pseudomonas putida strain, the deposit number is CGMCC No. 21602. TCD-1 strain is Pseudomonas methylotrophicus Methylorubrum pseudosasae , the deposit number is CGMCC NO.24728. Z-90 strain is Burkholderia Burkholderia sp. , the preservation number is CGMCC No.9970, the first bacterial liquid, the second bacterial liquid and the third bacterial liquid are all fermentation liquids of the corresponding strains grown to the logarithmic phase in the culture medium.

[0012] According to an embodiment of the present application, in the culture medium, the volume ratio of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 1-2:1-2:1-2.

[0013] According to an embodiment of the present application, the total volume of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 12% of the volume of the culture medium.

[0014] A third aspect of the present invention provides a method for treating heap leaching cyanide tailings, comprising:

[0015] The cyanide tailings are circulated and leached with a composite bacterial agent.

[0016] According to the implementation mode of the present application, the step of cyclically eluting the cyanide tailings with a composite bacterial agent comprises:

[0017] Fill the cyanide tailings into the elution column.

[0018] The pH of the compound bacterial agent was adjusted to 9.

[0019] The composite bacterial agent is added into the elution column at a flow rate of 50-150 ml / min to elute the cyanide tailings, wherein the elution time is 7 days.

[0020] The composite bacterial community TDB-1 and TCD-1 used to treat the heap leaching cyanide tailings of gold mines can use cyanide, thiocyanide and metal-cyanide complexes as carbon sources and nitrogen sources for their own growth and metabolism, thereby effectively degrading cyanide, thiocyanide and metal-cyanide complexes. The surfactant produced by Z-90 bacteria can effectively leach heavy metals in the heap leaching cyanide tailings to achieve the effect of repair. The method of treating the heap leaching cyanide tailings of gold mines by the composite bacterial community has the advantages of simple operation, high reduction efficiency, stable effect, good impact resistance, low cost, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0022] Figure 1 This is a diagram of a rinsing device according to one embodiment of the present application;

[0023] Figure 2 The pH value of the composite bacterial community in Example 1 of the present invention is Pseudomonas putida TDB-1, Methylorubrum pseudosasae TCD-1 and Burkholderia sp. The performance of Z-90 bacteria; among them, Figure 2 (a) The effect of pH on its performance in degrading thiocyanate; Figure 2 (b) The effect of pH on its performance in degrading potassium ferrocyanide;

[0024] Figure 3 The effect of temperature on the composite bacterial community in Example 1 of the present invention Pseudomonas putida TDB-1, Methylorubrum pseudosasae TCD-1 and Burkholderia sp. The performance of Z-90 bacteria; among them, Figure 3 (a) The effect of temperature on its performance in degrading thiocyanate; Figure 3 (b) The effect of temperature on its performance in degrading potassium ferrocyanide;

[0025] Figure 4 The composite flora of different inoculation ratios in Example 1 of the present invention Pseudomonas putida TDB-1, Methylorubrum pseudosasae TCD-1 and Burkholderia sp. The performance of Z-90 bacteria; among them, Figure 4 (a) The effect of inoculation ratio on its performance in degrading thiocyanate; Figure 4 (b) The effect of inoculation ratio on its ability to degrade potassium ferrocyanide;

[0026] Figure 5 is the change in cyanide concentration in the eluent in Example 2 of the present invention and the cyanide content in the heap leaching cyanide tailings before and after leaching; wherein, Figure 5 (a) is its line graph; Figure 5 (b) is its bar graph;

[0027] Figure 6 is the change in thiocyanate concentration of the eluent in Example 2 of the present invention and the content of thiocyanate in the heap leaching cyanide tailings before and after leaching; wherein, Figure 6 (a) is its line graph; Figure 6 (b) is its bar graph;

[0028] Figure 7 is the change of arsenic concentration in the leaching solution and the arsenic content in the heap leaching cyanide tailings before and after leaching; Figure 7 (a) is its line graph; Figure 7 (b) is its bar graph.

[0029] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] 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.

[0031] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0032] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0033] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] The first aspect of the present invention provides a composite bacterial community for treating heap leaching cyanide tailings of gold mines, the composite bacterial community comprising TDB-1 strain, TCD-1 strain and Z-90 strain, TDB-1 strain is Pseudomonas putidastrain, and the preservation number is CGMCC No. 21602. TCD-1 strain is Methylorubrumpseudosasae, and the preservation number is CGMCC No. 24728. Z-90 strain is Burkholderia sp., and the preservation number is CGMCC No. 9970.

[0035] Among them, the TDB-1 strain (Pseudomonas putida) was isolated by the applicant from domestic sewage in Yanghu Wetland, Changsha City, Hunan Province. The bacteria is currently deposited in the General Microbiology Center of China Culture Collection Administration, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code 100101, Deposit Number CGMCC No.21602, and the deposit date is January 7, 2021.

[0036] The TCD-1 strain (Methylorubrum pseudosasae) was isolated by the applicant from the sludge of the gold mine heap leaching site in Longnan City, Gansu Province. The bacterium is currently deposited in the General Microbiology Center of China Culture Collection Administration, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code 100101, Collection Number CGMCC No. 24728, Collection Date April 19, 2022.

[0037] The Z-90 strain (Burkholderia sp.) was isolated by the applicant from a sewer sludge sample from a restaurant in Changsha City. The strain is currently deposited in the General Microbiology Center of China Culture Collection Administration, located at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code 100101, with the deposit number CGMCC No.9970 and the deposit date November 1, 2014.

[0038] The composite bacterial community TDB-1 and TCD-1 used to treat the heap leaching cyanide tailings of gold mines can use cyanide, thiocyanide and metal-cyanide complexes as carbon sources and nitrogen sources for their own growth and metabolism, thereby effectively degrading cyanide, thiocyanide and metal-cyanide complexes. The surfactant produced by Z-90 bacteria can effectively leach heavy metals in the heap leaching cyanide tailings to achieve the effect of repair. The method of treating the heap leaching cyanide tailings of gold mines by the composite bacterial community has the advantages of simple operation, high reduction efficiency, stable effect, good impact resistance, low cost, etc.

[0039] The second aspect of the present invention provides a composite bacterial agent for treating heap leaching cyanide tailings of gold mines, comprising a culture medium and TDB-1 strain, TCD-1 strain and Z-90 strain dispersed in the culture medium. The TDB-1 strain is Pseudomonas putida Pseudomonas putida strain The deposit number is CGMCC No. 21602. TCD-1 strain is Pseudomonas methylotrophicus Methylorubrum pseudosasae , the deposit number is CGMCC NO. 24728. Z-90 strain is Burkholderia Burkholderia sp. , the deposit number is CGMCC No.9970.

[0040] In some embodiments, the culture medium is LB liquid culture medium, and the TDB-1 strain, TCD-1 strain, and Z-90 strain are dispersed in the LB liquid culture medium, such as expanding the culture in the LB liquid culture medium to form a composite bacterial agent. The LB liquid culture medium is Luria-Bertani medium, and its preparation method is: 10 g of tryptone, 5 g of yeast extract, and 10 g of NaCl are dissolved in 1 L of deionized water, steam sterilized at 121°C under high pressure for 20 minutes, and adjusted to pH = 9 with sterile 1 mol / L NaOH solution.

[0041] The third aspect of the present invention provides a method for preparing a composite bacterial agent for treating heap leaching cyanide tailings of gold mines, comprising:

[0042] The first bacterial liquid of the TDB-1 strain, the second bacterial liquid of the TCD-1 strain, and the third bacterial liquid of the Z-90 strain were added to the culture medium for expansion culture, and cultured at pH 9 and 30±2°C for at least 2 days to obtain a composite bacterial agent. Among them, the TDB-1 strain is Pseudomonas putida Pseudomonas putida strain The deposit number is CGMCC No. 21602. TCD-1 strain is Pseudomonas methylotrophicus Methylorubrum pseudosasae , the deposit number is CGMCC NO. 24728. Z-90 strain is Burkholderia Burkholderia sp. , the preservation number is CGMCC No.9970, the first bacterial liquid, the second bacterial liquid and the third bacterial liquid are all fermentation liquids of the corresponding strains grown to the logarithmic phase in the culture medium.

[0043] In some embodiments, the TDB-1 strain, TCD-1 strain, and Z-90 strain are first cultured in LB liquid culture medium, respectively, and each strain is grown to the logarithmic phase to obtain the corresponding first bacterial liquid, second bacterial liquid, and third bacterial liquid. Then, the fermentation broth in the logarithmic phase is added to a culture bucket containing LB liquid culture medium in proportion for expansion culture, and the pH is adjusted to 9 with NaOH solution, and cultured at 30±2° C. for at least 2 days.

[0044] Exemplarily, single colonies of the TDB-1 strain, TCD-1 strain and Z-90 strain were picked from the plates and placed in 20 mL LB liquid culture medium. When the OD600 reached 0.9, they were transferred to 100 mL LB culture medium for culture. When the OD600 of each culture medium reached 0.9, they were transferred to 100 mL LB culture medium for expansion culture for 2-3 days, and the bacterial liquid was harvested.

[0045] According to an embodiment of the present application, in the culture medium, the volume ratio of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 1-2: 1-2: 1-2. In some embodiments, the volume ratio of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 1:1:1.

[0046] According to an embodiment of the present application, the total volume of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 12% of the volume of the culture medium.

[0047] A third aspect of the present invention provides a method for treating heap leaching cyanide tailings, comprising:

[0048] The cyanide tailings are circulated and leached with a composite bacterial agent.

[0049] Exemplarily, the cyanide tailings are filled in a leaching column, and the composite bacterial agent is injected into the leaching column through the liquid outlet end of a delivery pump (such as a peristaltic pump), and the composite bacterial agent leaches the soil from top to bottom.

[0050] A liquid collecting mechanism is placed at the lower end of the elution column, and the liquid collecting mechanism receives the composite bacterial agent after elution in the elution column. The liquid inlet end of the delivery pump is placed in the liquid collecting mechanism to return the composite bacterial agent to the elution column to achieve cyclic spraying.

[0051] In some embodiments, the step of cyclically eluting the cyanide tailings with a composite bacterial agent comprises:

[0052] S10: Fill the cyanide tailings into the elution column.

[0053] Exemplarily, the cyanide tailings are filled into the elution column so that the soil height reaches 1.5 m.

[0054] S20: Adjust the pH of the composite bacterial agent to 9.

[0055] Exemplarily, the pH is adjusted to 9 using 1 mol / L NaOH solution.

[0056] S30: Add the composite bacterial agent into the elution column at a flow rate of 50-150 ml / min to elute the cyanide tailings, wherein the elution time is 7 days.

[0057] Example 1 Determination of the optimal conditions for composite bacterial flora

[0058] 1) Determination of the optimal pH value of the composite bacterial community

[0059] Will Pseudomonas putida TDB-1 (i.e. TDB-1 strain), Methylorubrum pseudosasae TCD-1 (i.e., TCD-1 strain) and Burkholderia sp. Z-90 (i.e., Z-90 strain) was cultured to a turbid OD value of 0. 600 = 0.9.

[0060] According to the total inoculation volume of 12% ( Pseudomonas putida TDB-1 4%, Methylorubrum pseudosasae TCD-1 4% and Burkholderia sp.Z-90 4%) in a volume ratio of 1:1:1 to form a composite bacterial community treatment group.

[0061] Different pH values ​​(pH=6, 7, 8, 9, 10, 11) were set, and the composite bacterial community treatment group was cultured in an ionic culture medium containing potassium thiocyanide and potassium ferrocyanide at 30℃ and 150rpm for 7 days. Samples were taken and centrifuged at regular intervals, and the concentrations of thiocyanide and potassium ferrocyanide in the supernatant were measured to determine the optimal pH value for the composite bacterial community to degrade thiocyanide.

[0062] The degradation of thiocyanate (i.e. thiocyanate ion) and potassium ferrocyanide by strains at different pH values ​​is shown in Figure 2. Figure 2 (a) Figure 2 (b) As shown in Table 1 and Table 2, it can be seen that the optimal pH is 9.

[0063] Table 1 Effect of pH on the degradation performance of composite bacterial community

[0064]

[0065] Table 2 Effect of pH on the degradation of potassium ferrocyanide by composite bacterial community

[0066]

[0067] 2) Determination of the optimal temperature for composite bacterial flora

[0068] Will Pseudomonas putida TDB-1, Methylorubrum pseudosasae TCD-1 and Burkholderia sp. Z-90 pure culture to the turbidity OD of the bacterial solution 600 = 0.9.

[0069] According to the total inoculation volume of 12% ( Pseudomonas putida TDB-1 4%, Methylorubrum pseudosasae TCD-1 4%, Burkholderia sp. Z-90 4%) in a volume ratio of 1:1:1 to form a composite bacterial community treatment group.

[0070] Different temperature values ​​(20℃, 25℃, 30℃, 35℃, 40℃, 45℃) were set, and the composite bacterial community treatment group was cultured in an ion culture medium containing potassium thiocyanide and potassium ferrocyanide at 150rpm for 7 days. Samples were taken and centrifuged at regular intervals, and the concentrations of thiocyanide and potassium ferrocyanide in the supernatant were measured to determine the optimal temperature value for the composite bacterial community to degrade thiocyanide.

[0071] The degradation of thiocyanate and potassium ferrocyanide by strains at different temperatures is shown in Figure 2. Figure 3 (a) and Figure 3(b), Table 3 and Table 4 show that the optimal temperature is 30°C.

[0072] Table 3 Effect of temperature on the degradation performance of composite bacterial agent for thiocyanate

[0073]

[0074] Table 4 Effect of temperature on the degradation of potassium ferrocyanide by composite bacterial agent

[0075]

[0076] 3) Determination of the optimal inoculation ratio of composite bacterial flora

[0077] Will Pseudomonas putida TDB-1, Methylorubrum pseudosasae TCD-1 and Burkholderia sp. Z-90 pure culture to the turbidity OD of the bacterial solution 600 = 0.9.

[0078] Under the optimal pH and temperature conditions, different inoculation ratios were set ( Pseudomonas putida TDB-1: Methylorubrum pseudosasae TCD-1: Burkholderia sp. Z-90=1:1:1, Pseudomonas putida TDB-1: Methylorubrum pseudosasae TCD-1: Burkholderia sp. Z-90 =2:1:1, Pseudomonas putida TDB-1: Methylorubrum pseudosasae TCD-1: Burkholderia sp. Z-90=1:2:1, Pseudomonas putida TDB-1: Methylorubrum pseudosasae TCD-1: Burkholderia sp. Z-90=1:1:2) inoculation to form a composite bacterial community treatment group.

[0079] The composite bacterial community treatment group was cultured in an ionic culture medium containing potassium thiocyanide and potassium ferrocyanide at 150rpm for 7 days. Samples were taken and centrifuged at regular intervals, and the concentrations of thiocyanide and potassium ferrocyanide in the supernatant were measured to determine the optimal inoculation ratio for the composite bacterial community to degrade thiocyanide.

[0080] The degradation of thiocyanate and potassium ferrocyanide by strains at different inoculation ratios is shown in Figure 2. Figure 4 (a) Figure 4 (b) and Tables 5 and 6 show that the optimal inoculation ratio is 1:1:1.

[0081] Table 5 Effect of inoculation ratio on the degradation performance of mixed bacterial agents for thiocyanide

[0082]

[0083] Table 6 Effect of inoculation ratio on the degradation performance of potassium ferrocyanide by mixed bacterial agents

[0084]

[0085] Example 2 Composite bacterial flora elution process

[0086] The optimal conditions (pH = 9, Pseudomonas putida TDB-1: Methylorubrum pseudosasae TCD-1: Burkholderia sp. The composite bacterial community was used to treat the gold heap leaching cyanide tailings at 30°C (Z-90 = 1:1:1, temperature 30°C). The specific method is as follows:

[0087] Will Pseudomonas putida TDB-1, Methylorubrum pseudosasae TCD-1 and Burkholderia sp. Z-90 picked a single colony from the plate and put it into 20 mL LB liquid medium. 600 When the OD value reaches 0.9, inoculate into 10L LB medium for expansion culture. 600 When the pH reaches 0.9, harvest the bacterial solution at a volume ratio of 1:1:1. Add an appropriate amount of sodium hydroxide to the bacterial culture barrel to adjust the pH to 9.0. Weigh an appropriate amount of sodium hydroxide in pure water to adjust the pH to 9.0 to prepare an alkaline solution as a blank control.

[0088] The gold mine heap leaching cyanide tailings are placed in the leaching column 20, so that the soil height reaches 1.5m, and there is a sieve hole 50 below the leaching column 20. Figure 1 , use the delivery pump 40 to inject the expanded bacterial liquid into the spray mechanism 10. The bacterial liquid is sprayed out from the spray mechanism 10, eluting the soil from top to bottom, and a liquid collecting mechanism 30, such as (liquid collecting tank, liquid collecting channel), is placed at the lower end of the elution column 20. The liquid inlet end of the delivery pump 40 (such as a peristaltic pump) is placed in the liquid collecting mechanism 30 to allow the bacterial liquid to return to the spray mechanism 10 to achieve circulating spraying. The flow rate of the composite bacterial community eluent injected into the elution column 20 is 50-150 ml / min, and the elution time is 7 days. Samples are taken at regular intervals to measure the concentrations of cyanide, thiocyanide, and heavy metals in the eluent. The measurement results are as follows Figure 5 (a) and Figure 5 (b) Figure 6 (a) and Figure 6 (b) and Figure 7 (a) and Figure 7 (b) and shown in Tables 7 to 9.

[0089] Table 7 Cyanide concentrations of each group at different times

[0090]

[0091] Table 8 Thiocyanide concentrations in each group at different times

[0092]

[0093] Table 9 As concentration of each group at different time

[0094]

[0095] Depend on Figure 5 It can be seen that the alkaline solution treatment group cannot effectively degrade cyanide, while the composite bacterial community leaching can effectively elute and degrade cyanide. The cyanide content in the soil after leaching reaches the control value standard for Class I land in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard (Trial)" (GB36600-2018), and the cyanide in the leaching solution meets the technical requirements for pollution control of cyanide slag tailings pond disposal in the "Technical Specifications for Cyanide Slag Pollution Control in the Gold Industry" (HJ 943-2018).

[0096] from Figure 6 It can be seen that the alkali solution treatment group could not effectively degrade thiocyanide, while the thiocyanate concentration in the elution solution of the composite bacterial community treatment group gradually decreased, indicating that composite bacterial community elution has a good effect on degrading thiocyanate.

[0097] Depend on Figure 7 It can be seen that as the leaching progresses, the arsenic concentration in the leaching solution gradually increases, while the arsenic content in the heap leaching cyanide tailings after leaching is significantly reduced, indicating that arsenic is eluted from the tailings with the leaching solution. Therefore, the composite bacterial community can effectively repair the heap leaching cyanide tailings of gold mines, and the composite bacterial community constructed by these three strains with different characteristics is an effective way to repair complex soils.

[0098] The above technical solutions of the present invention are only preferred embodiments of the present invention, and the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A composite bacterial agent for treating heap leaching cyanide tailings of gold mines, characterized in that: The method comprises a culture medium and TDB-1 strain, TCD-1 strain and Z-90 strain dispersed in the culture medium; the TDB-1 strain is Pseudomonas putida Pseudomonas putida strain , the deposit number is CGMCC No.21602; the TCD-1 strain is Pseudomonas methylophyllae Methylorubrum pseudosasae , the deposit number is CGMCC NO. 24728; the Z-90 strain is Burkholderia Burkholderia sp. , the deposit number is CGMCC No.9970; the volume ratio of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 1-2:1-2:1-2, and the first bacterial liquid, the second bacterial liquid and the third bacterial liquid are respectively fermentation liquids of TDB-1 strain, TCD-1 strain and Z-90 strain grown to logarithmic phase in culture medium.

2. The composite bacterial agent according to claim 1, characterized in that The culture medium is LB liquid culture medium.

3. A method for preparing a composite bacterial agent for treating heap leaching cyanide tailings of gold mines, characterized in that: include: The first bacterial liquid of the TDB-1 strain, the second bacterial liquid of the TCD-1 strain, and the third bacterial liquid of the Z-90 strain are added to the culture medium for expansion culture, and cultured at pH 9 and 30±2° C. for at least 2 days to obtain the composite bacterial agent; Wherein, the TDB-1 strain is Pseudomonas putida Pseudomonas putida strain , the deposit number is CGMCC No.21602; the TCD-1 strain is Pseudomonas methylophyllae Methylorubrum pseudosasae , the deposit number is CGMCCNO. 24728; the Z-90 strain is Burkholderia Burkholderia sp. , the preservation number is CGMCC No.9970, the first bacterial liquid, the second bacterial liquid and the third bacterial liquid are all fermentation liquids of the corresponding strains grown to the logarithmic phase in the culture medium.

4. The preparation method according to claim 3, characterized in that: In the culture medium, the volume ratio of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 1-2:1-2:1-2.

5. The preparation method according to claim 4, characterized in that: The total volume of the first bacterial liquid, the second bacterial liquid and the third bacterial liquid is 12% of the volume of the culture medium.

6. A method for treating heap leaching cyanide tailings, characterized in that: include: The heap leaching cyanide tailings are cyclically leached using the composite bacterial agent described in claim 1 or 2.

7. The method for treating heap leaching cyanide tailings according to claim 6, characterized in that: The step of using a composite bacterial agent to circulate and wash the heap leaching cyanide tailings comprises: Filling the heap leaching cyanide tailings into the leaching column; The composite bacterial agent is adjusted to a pH of 9; The composite bacterial agent is added to the elution column at a flow rate of 50-150 ml / min to elute the heap leaching cyanide tailings, wherein the elution time is 7 days.

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