Conditioning agent for reducing ore leaching acid and heavy metal and use method

Abstract

The invention discloses a conditioning agent for reducing ore leaching acid and heavy metal and a using method, the conditioning agent contains a microbial agent and lime milk, the microbial agent is sulfur reducing bacteria or acidophilic heterotrophic bacteria, the solid content of a microbial agent solution is 12%-25%, and the dosage of the microbial agent is 10%-30% of the mass of ore needing to be conditioned. The conditioner can adjust the pH value of the natural acid leaching environment of ore to form a certain stabilization effect, and the added biological agent competes with microorganisms related to acid production in the original environment to inhibit metabolism and growth of the microorganisms, reduce generation of acid and maintain the pH environment, so that the stable conditioning effects of weakening the acid environment and reducing heavy metal leaching are achieved.

Description

Technical Field

[0001] The invention relates to the field of soil and mine restoration, and in particular to a conditioning agent for reducing ore leaching acid and heavy metals and a use method thereof. Background Art

[0002] With the increase of mining activities, the problem of natural leaching acid and heavy metal pollution in ore has become increasingly serious. In addition, there is a situation that the mine stone used as foundation fill has also caused acid and heavy metal leaching pollution. Natural leaching acid refers to the acidic substances spontaneously generated by ore in the natural environment due to the action of water and oxygen. After the sulfide minerals in the ore are exposed to air and water, they often undergo oxidation reactions to generate sulfuric acid, which leads to the acidification of soil and groundwater. This acidic environment not only has a negative impact on the ecological environment around the mining area, but also causes heavy metal elements in the ore, such as lead, zinc, and copper, to be dissolved and released into the environment, posing a serious threat to the surrounding water bodies, soil and organisms. In addition, in these mining environments, many microorganisms, especially sulfur-oxidizing bacteria (such as Thiobacillus bacteria), can oxidize sulfides to generate sulfuric acid, exacerbating the acidification of the environment. These microorganisms oxidize the sulfur element in the ore into sulfuric acid through metabolism, further reducing the pH value of the environment, promoting the dissolution and release of heavy metals, and leading to further deterioration of the ecosystem.

[0003] At present, there are various methods for controlling and treating the natural leaching of acid and heavy metals from ores, including physical, chemical and biological means. Common methods include the application of limestone or lime milk, which are alkaline substances that can neutralize the acidic environment, thereby increasing the pH value and slowing down the leaching of heavy metals. However, these traditional methods still face some challenges in their application. First, simple chemical neutralization methods often cannot maintain a stable pH environment for a long time, and the pH value is likely to drop again due to the continuous generation of acidic substances. Secondly, the removal or solidification effect of heavy metals is also affected by the acidic environment, resulting in low remediation efficiency. In addition, the ecosystem in the mining area is often affected by a variety of microorganisms, which may further aggravate the formation of the acidic environment and the release of heavy metals through metabolic activities.

[0004] In order to effectively respond to these challenges, in recent years, some researchers have tried to combine microbial technology with traditional chemical methods, using the bioremediation ability of microorganisms to regulate the acidic environment in soil and water and reduce the leaching of heavy metals. However, there are still some problems with the current microbial remediation technology, such as the unstable activity of biological agents, which are difficult to survive in harsh acidic environments for a long time. In addition, how to form effective competition with microorganisms in the natural environment to inhibit the metabolic activities of harmful microorganisms is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of acidic environment and heavy metal pollution caused by natural conditions and microbial action during the natural leaching of ore.

[0006] To achieve the above-mentioned purpose, the present invention provides a conditioning agent for reducing leaching acid and heavy metals in ore, the conditioning agent contains microbial agent and lime milk, the concentration of the lime milk is 5%~15%, and the amount of lime milk added is 10%~30% of the mass of the ore to be conditioned; the microbial agent is sulfur-reducing bacteria or acidophilic heterotrophic bacteria, the solid content of the microbial agent solution is 12%~25%, and the amount of the microbial agent added is 10%~30% of the mass of the ore to be conditioned.

[0007] Preferably, in any of the above schemes, the concentration of the lime milk is any value within the range of 5% to 15%, such as 5%, 10%, or 15%.

[0008] Preferably, in any of the above schemes, the concentration of lime milk is 10%.

[0009] In any of the above schemes, preferably, the amount of lime milk added is any value within the range of 10% to 30% of the mass of the ore to be conditioned, such as 10%, 15%, 20%, 25%, or 30%.

[0010] Preferably, in any of the above schemes, the microbial agent is composed of sulfur-reducing bacteria or acidophilic heterotrophic bacteria and organic matter, the solid content of the microbial agent solution is 12% to 25%; and the dosage of the microbial agent is 10% to 30% of the mass of the ore to be conditioned.

[0011] The solid content of the microbial agent solution is any value within the range of 12% to 25%, such as 12%, 15%, 20%, 25%, 30%. The dosage of the microbial agent is any value within the range of 10% to 30% of the ore quality to be conditioned, such as 10%, 15%, 20%, 25%, 30%.

[0012] Organic matter includes glucose, auxiliary carbon source and inorganic salt, wherein the mass ratio of glucose, auxiliary carbon source and inorganic salt is 2:3:1; the bacterial content of sulfur-reducing bacteria or acidophilic heterotrophic bacteria is 10 7 Up to 10 10 colony forming units.

[0013] The auxiliary carbon source is any one or more of glycerol, lactose, and sodium acetate, and the inorganic salt is any one or more of magnesium sulfate, sodium chloride, ammonia water or amino acid, and potassium dihydrogen phosphate.

[0014] Preferably, in any of the above schemes, the solid content of the microbial agent is 17%, and the dosage of the microbial agent is 20% of the mass of the ore to be conditioned.

[0015] In any of the above schemes, it is preferred that the sulfur-reducing bacteria is any one of Desulfovibrio and Desulfovibrio; and the acidophilic heterotrophic bacteria is any one of Acidophilus and Acidosporea.

[0016] The present application also discloses a method for using the above conditioning agent for reducing ore leaching acid and heavy metals, comprising the following steps: (1) First, add lime milk to the ore to be conditioned, wherein the concentration of the lime milk is 5% to 15%, and the amount of lime milk added is 10% to 30% of the mass of the ore to be conditioned, so that the pH value of the environment is adjusted to 7 to 8; (2) To ensure the stability of pH value, re-measure pH value every 3 to 7 days after adding lime milk to ensure that it is maintained between 7 and 8. If pH value fails to reach 7, continue to add lime milk; (3) After the pH value stabilizes, add microbial agents to the ore. The microbial agents are composed of sulfur-reducing bacteria or acidophilic heterotrophic bacteria and organic matter, and are prepared into a solution with a solid content of 12% to 25%. The amount of microbial agent added is 10% to 30% of the mass of the ore to be conditioned.

[0017] Preferably, in step (3), the sulfur-reducing bacteria is any one of Desulfovibrio and Desulfovibrio.

[0018] In any of the above schemes, preferably, in step (3), the acidophilic heterotrophic bacteria are any one of acidophilic bacteria and acidocytophilic bacteria.

[0019] Preferably, in any of the above schemes, the solid content of the microbial agent is 17%, and the dosage of the microbial agent is 20% of the mass of the ore to be conditioned.

[0020] In any of the above schemes, preferably, in step (3), the microbial agent preparation method is: (1) Cultivate microorganisms under laboratory conditions, collect the cells after they reach the logarithmic growth phase, remove the culture medium by centrifugation or filtration, and retain the wet weight; (2) Mixing glucose, auxiliary carbon source and inorganic salt to prepare a nutrient matrix; (3) Adjust the water content of the nutrient matrix so that when it is subsequently mixed with microorganisms, the overall solid content meets the requirements.

[0021] By applying the conditioning agent for reducing ore leaching acid and heavy metals of the present application, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0022] This conditioning agent can not only effectively reduce the leaching concentration of heavy metals, but also maintain a stable repair effect for a long time.

[0023] Beneficial Effects The invention provides a conditioning agent for reducing acid and heavy metal leaching in ore and a method for using the conditioning agent. The conditioning agent contains a microbial agent and lime milk. By combining the lime milk with the biological agent and utilizing the competitive effect between aerobic bacteria and harmful microorganisms in the mining environment, the conditioning agent can adjust the pH value of the natural acid leaching environment of the ore to form a certain stabilization effect. The conditioning agent can not only effectively neutralize the acidic environment and increase the pH value, but also the added biological agent can compete with the acid-producing microorganisms in the original environment, and can also inhibit the growth and metabolism of harmful microorganisms and reduce the generation of acid, thereby maintaining a relatively stable pH environment, and ultimately achieving the purpose of reducing heavy metal leaching and protecting the ecological environment.

[0024] Compared with existing remediation methods, the conditioner of the present invention is more economical and efficient and is suitable for a wide range of mine remediation applications. DETAILED DESCRIPTION

[0025] Example 1 The invention discloses a conditioning agent for reducing ore leaching acid and heavy metals. The conditioning agent comprises lime milk and microbial agent, and the concentration of the lime milk is 5%.

[0026] The method of using the conditioner is: first, add lime milk to the ore that needs to be conditioned, and the amount of lime milk added is 30% of the mass of the ore that needs to be conditioned, so that the environmental pH value is adjusted to between 7 and 8.

[0027] To ensure the stability of the pH value, retest the pH value at intervals of 3 to 7 days after the addition of lime milk to ensure that it remains between 7 and 8. If the pH fails to reach 7, continue to add lime milk.

[0028] After the pH value stabilizes, a microbial agent consisting of sulfur-reducing bacteria and organic matter is added to the ore in a solution with a solid content of 12%.

[0029] The organic matter includes glucose, glycerol and magnesium sulfate, among which the mass ratio of glucose, glycerol and magnesium sulfate is 2:3:1; the content of sulfur-reducing bacteria is 10 7 colony forming units.

[0030] The method for preparing the microbial agent is as follows: Step 1: Cultivate microorganisms Objective: To cultivate microbial sulfur-reducing bacteria to the logarithmic growth phase and collect the bacteria.

[0031] 1) Choose the culture medium: Choose the appropriate culture medium according to the needs of sulfur-reducing bacteria. Common culture medium components include: Glucose: As the main carbon source, the concentration is usually 1%-2% (w / v) to promote the growth of sulfur-reducing bacteria.

[0032] Inorganic salts: such as sodium chloride (NaCl), magnesium sulfate , potassium dihydrogen phosphate ,ammonia Etc., provide essential minerals and ions, with concentrations usually between 0.1%-1% (w / v).

[0033] Sulfur source: Sulfur-reducing bacteria need a sulfur source for their reduction reaction, usually sulfate As a sulfur source, the concentration can be set at 0.5%-1% (w / v).

[0034] 2) Culture conditions: a. Temperature: Generally between 30-37°C. The specific temperature should be set according to the optimal growth temperature of sulfur-reducing bacteria.

[0035] b. pH: According to the needs of sulfur-reducing bacteria, the pH should usually be adjusted to between 7.0 and 8.0.

[0036] c. Stirring / shaking: maintain dissolved oxygen and help bacterial growth. It is recommended to be between 200-250rpm.

[0037] d. Cultivation time: Depending on the growth rate of the strain, the cultivation time is usually 24-72 hours, until the bacteria enter the logarithmic growth phase.

[0038] 3) Collecting bacteria: a. Centrifugation: After the bacterial culture is completed, use a centrifuge to collect the bacteria. Common centrifugation conditions are 3000-5000rpm for 10-20 minutes.

[0039] b. Filtration: If there is no centrifuge, the bacteria can be filtered through a filter screen or filter paper.

[0040] c. Wet weight: The culture medium is removed from the collected bacteria and the wet weight is retained for subsequent steps.

[0041] Step 2: Prepare the nutrient matrix Objective: To prepare a nutrient matrix suitable for the growth and reproduction of sulfur-reducing bacteria.

[0042] 1) Carbon source (such as glucose): Glucose: As the main carbon source, the concentration is generally 1%-5% (w / v), which can be adjusted according to the carbon source requirements of the bacteria. Usually the initial concentration is selected in a lower range, such as 2% (w / v). If the sulfur-reducing bacteria have a higher demand for carbon sources, it can be increased appropriately.

[0043] 2) Auxiliary carbon source: Some other carbon sources can be selected as auxiliary, such as glycerol, lactose, sodium acetate, etc., and the concentration is usually 0.5%-2% (w / v), which is added according to the growth needs of microorganisms. For example, when glycerol is used as an auxiliary carbon source, the concentration is usually controlled at about 1%.

[0044] 3) Inorganic salts: Mainly provides essential minerals, common inorganic salt components include: Magnesium sulfate : 0.1%-0.5% (w / v).

[0045] Sodium chloride (NaCl): 0.1%-0.3% (w / v).

[0046] ammonia or amino acids: provide a nitrogen source, the concentration is usually 0.1%-0.5% (w / v).

[0047] Potassium dihydrogen phosphate : 0.05%-0.2% (w / v).

[0048] The ratio of inorganic salts should be adjusted according to the needs of sulfur-reducing bacteria. Excessive salt concentration may inhibit the growth of microorganisms.

[0049] Prepare the nutrient matrix: Mix all the above ingredients at the required concentration and dissolve them in deionized water. According to the requirements of sulfur-reducing bacteria, ensure that the substrate has a good nutrient supply to ensure bacterial growth.

[0050] Step 3: Adjust the water content to achieve a total solids content of 12% Goal: Adjust the moisture content of the final mix to ensure an overall solids content of 12% when mixed with the wet weight of the microbial mass.

[0051] 1) Adjustment of water content of nutrient matrix: First, calculate the initial solid content of the nutrient matrix (the mass after water removal). Generally, the initial solid content can be obtained by drying a certain amount of nutrient matrix to a constant weight and measuring its dry weight.

[0052] 2) Addition of wet heavy bacteria: a. Assuming that the moisture content of the wet weight of the bacteria is approximately 90%-95% (the specific amount can be determined based on the experimental situation), the amount of bacteria added needs to be adjusted based on the wet weight ratio.

[0053] b. Assuming that 1 kg of wet weight of bacteria (containing about 0.1-0.05 kg of solids) has been prepared, it needs to be mixed with the nutrient matrix to ensure that the solid content in the mixture is 12%.

[0054] The sulfur-reducing bacteria are Desulfovibrio, and the dosage of the microbial agent is 30% of the mass of the ore to be conditioned.

[0055] Through the application of this conditioner, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0056] This conditioner can not only effectively reduce the leaching concentration of heavy metals, but also maintain a stable repair effect for a long time.

[0057] The present invention provides a novel ore natural leaching acid and heavy metal conditioning agent, which combines lime milk with biological bacterial agents and utilizes the competitive effect between aerobic bacteria and harmful microorganisms in the mining environment, thereby not only effectively neutralizing the acidic environment and improving the pH value, but also inhibiting the growth and metabolism of harmful microorganisms and reducing acid generation, thereby maintaining a relatively stable pH environment, and ultimately achieving the purpose of reducing heavy metal leaching and protecting the ecological environment.

[0058] Compared with existing remediation methods, the conditioner of the present invention is more economical and efficient and is suitable for a wide range of mine remediation applications.

[0059] Example 2 A conditioning agent for reducing ore leaching acid and heavy metals, the conditioning agent comprises lime milk and microbial agent, and the concentration of lime milk is 10%.

[0060] The method of using the conditioner is: first, add lime milk to the ore that needs to be conditioned, and the amount of lime milk added is 20% of the mass of the ore that needs to be conditioned, so that the environmental pH value is adjusted to between 7 and 8.

[0061] To ensure the stability of the pH value, retest the pH value at intervals of 3 to 7 days after the addition of lime milk to ensure that it remains between 7 and 8. If the pH fails to reach 7, continue to add lime milk.

[0062] After the pH value stabilizes, a microbial agent consisting of sulfur-reducing bacteria and organic matter is added to the ore to form a solution with a solid content of 17%.

[0063] The organic matter includes glucose, glycerol and sodium chloride, among which the mass ratio of glucose, glycerol and sodium chloride is 2:3:1; the bacterial content of sulfur-reducing bacteria is 10 10 colony forming units.

[0064] The preparation method of the microbial agent is the same as that of Example 1, and the overall solid content reaches 17%.

[0065] The sulfur-reducing bacteria are desulfurizing enterobacteria, and the dosage of the microbial agent is 20% of the mass of the ore to be conditioned.

[0066] Through the application of this conditioner, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0067] Example 3 A conditioning agent for reducing ore leaching acid and heavy metals, the conditioning agent comprises lime milk and microbial agent, and the concentration of lime milk is 15%.

[0068] The method of using the conditioner is: first, add lime milk to the ore that needs to be conditioned, and the amount of lime milk added is 10% of the mass of the ore that needs to be conditioned, so that the environmental pH value is adjusted to between 7 and 8.

[0069] To ensure the stability of the pH value, retest the pH value at intervals of 3 to 7 days after the addition of lime milk to ensure that it remains between 7 and 8. If the pH fails to reach 7, continue to add lime milk.

[0070] After the pH value stabilizes, a microbial agent is added to the ore. The agent consists of acidophilic heterotrophic bacteria and organic matter and is configured into a solution with a solid content of 25%.

[0071] The organic matter includes glucose, sodium acetate and ammonia water, wherein the mass ratio of glucose, sodium acetate and ammonia water is 2:3:1; the bacterial content of acidophilic heterotrophic bacteria is 10 8 colony forming units.

[0072] The preparation method of the microbial agent is the same as that of Example 1, and the overall solid content reaches 25%.

[0073] The acidophilic heterotrophic bacteria are acidophilic bacteria, and the dosage of the microbial agent is 15% of the mass of the ore to be conditioned.

[0074] Through the application of this conditioner, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0075] Example 4 A conditioning agent for reducing ore leaching acid and heavy metals, the conditioning agent comprises lime milk and microbial agent, and the concentration of lime milk is 12%.

[0076] The method of using the conditioner is: first, add lime milk to the ore that needs to be conditioned, and the amount of lime milk added is 15% of the mass of the ore that needs to be conditioned, so that the environmental pH value is adjusted to between 7 and 8.

[0077] To ensure the stability of the pH value, retest the pH value at intervals of 3 to 7 days after the addition of lime milk to ensure that it remains between 7 and 8. If the pH fails to reach 7, continue to add lime milk.

[0078] After the pH value stabilizes, a microbial agent is added to the ore. The agent consists of acidophilic heterotrophic bacteria and organic matter and is configured into a solution with a solid content of 15%.

[0079] The organic matter includes glucose, lactose and potassium dihydrogen phosphate, among which the mass ratio of glucose, lactose and potassium dihydrogen phosphate is 2:3:1; the bacterial content of acidophilic heterotrophic bacteria is 10 9 colony forming units.

[0080] The preparation method of the microbial agent is the same as that of Example 1, and the overall solid content reaches 15%.

[0081] The acidophilic heterotrophic bacteria are acidocytosis, and the dosage of the microbial agent is 25% of the mass of the ore to be conditioned.

[0082] Through the application of this conditioner, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0083] Example 5 A conditioning agent for reducing ore leaching acid and heavy metals, the conditioning agent comprises lime milk and microbial agent, and the concentration of lime milk is 10%.

[0084] The method of using the conditioner is: first, add lime milk to the ore that needs to be conditioned, and the amount of lime milk added is 12% of the mass of the ore that needs to be conditioned, so that the environmental pH value is adjusted to between 7 and 8.

[0085] To ensure the stability of the pH value, retest the pH value at intervals of 3 to 7 days after the addition of lime milk to ensure that it remains between 7 and 8. If the pH fails to reach 7, continue to add lime milk.

[0086] After the pH value stabilizes, a microbial agent consisting of sulfur-reducing bacteria and organic matter is added to the ore in a solution with a 20% solid content.

[0087] Organic matter includes glucose, glycerol and amino acids, among which the mass ratio of glucose, glycerol and amino acids is 2:3:1; the content of sulfur-reducing bacteria is 10 10 colony forming units.

[0088] The preparation method of the microbial agent is the same as that of Example 1, and the overall solid content reaches 15%.

[0089] The sulfur-reducing bacteria are desulfurizing enterobacteria, and the dosage of the microbial agent is 22% of the mass of the ore to be conditioned.

[0090] Through the application of this conditioner, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0091] Example 6 A conditioning agent for reducing ore leaching acid and heavy metals, the conditioning agent comprises lime milk and microbial agent, and the concentration of lime milk is 8%.

[0092] The method of using the conditioner is: first, add lime milk to the ore that needs to be conditioned, and the amount of lime milk added is 23% of the mass of the ore that needs to be conditioned, so that the environmental pH value is adjusted to between 7 and 8.

[0093] To ensure the stability of the pH value, retest the pH value at intervals of 3 to 7 days after the addition of lime milk to ensure that it remains between 7 and 8. If the pH fails to reach 7, continue to add lime milk.

[0094] After the pH value stabilizes, a microbial agent is added to the ore. The agent consists of acidophilic heterotrophic bacteria and organic matter and is configured into a solution with a solid content of 17%.

[0095] The organic matter includes glucose, lactose and sodium chloride, among which the mass ratio of glucose, lactose and sodium chloride is 2:3:1; the bacterial content of acidophilic heterotrophic bacteria is 10 7 colony forming units.

[0096] The preparation method of the microbial agent is the same as that of Example 1, and the overall solid content reaches 17%.

[0097] The acidophilic heterotrophic bacteria are acidophilic bacteria, and the dosage of the microbial agent is 18% of the mass of the ore to be conditioned.

[0098] Through the application of this conditioner, the acidic environment is effectively controlled and the pH value of the outflowing water is maintained above 6.

[0099] Example 7 This example demonstrates the effect of using the conditioning agent of the present invention to treat the natural leaching acid and heavy metals of the ore. The conditioning agent is composed of lime milk and microbial agents, and its effectiveness in reducing the acidic environment and reducing the leaching of heavy metals has been verified through experiments.

[0100] Untreated ore raw materials were selected for the experiment, and the specific operations were as follows: Lime milk treatment: Lime milk of the concentrations of Examples 1-6 were added to the ore raw materials, and the amount of lime milk added was 30%, 20%, 10%, 15%, 12%, and 23% of the mass of the ore to be conditioned, respectively, and the pH value of the ore environment was adjusted to 7-8. The pH value was re-measured regularly during the period to ensure that it remained within this range. After lime milk treatment, the concentration of heavy metals such as mercury and antimony in the ore was significantly reduced, as shown in the "Adding lime milk" column in Table 1-6.

[0101] Microbial agent configuration: 1. Cultivate microorganisms under laboratory conditions, collect the cells after they reach the logarithmic growth phase, remove the culture medium by centrifugation or filtration, and retain the wet weight.

[0102] 2. Mix glucose, auxiliary carbon source and inorganic salt to prepare a nutrient matrix.

[0103] 3. Adjust the moisture content of the nutrient matrix so that when it is subsequently mixed with the acidophilic heterotrophic bacteria, the overall solid content meets the requirements.

[0104] Microbial agent treatment: After lime milk treatment, the microbial agents of Examples 1-6 were further added to the ore, and the corresponding proportions of 30%, 20%, 15%, 25%, 22%, and 18% of the ore mass were added. After 3-5 weeks of microbial agent treatment, the heavy metal concentration was further reduced, and the concentrations of vanadium, mercury, aluminum, and antimony were reduced to the "Addition of microbial agents" column in Table 1-6, showing a significant heavy metal removal effect.

[0105] The results show that the conditioning agent of the present invention can effectively reduce the leaching of heavy metals in an acidic environment and keep the pH value of the wastewater above 6. At the same time, the treatment effect of the conditioning agent can be maintained for a long time, and compared with the existing remediation technology, it has the advantages of being economical and efficient.

[0106] Table 1 Changes in heavy metal content in ore of Example 1 Table 2 Changes in heavy metal content in ore from Example 2 Table 3 Changes in heavy metal content of ore in Example 3 Table 4 Changes in heavy metal content of ore in Example 4 Table 5 Changes in heavy metal content of ore in Example 5 Table 6 Changes in heavy metal content in ore of Example 6 The microorganisms used in this application are sulfur-reducing bacteria and acidophilic heterotrophic bacteria. 1. Sulfate-Reducing Bacteria (SRB) Representative species: Desulfovibrio ( Desulfovibrio spp.) and Desulfurobacterium ( Desulfotomaculum spp.) Mechanism of action: Sulfur-reducing bacteria reduce sulfate to sulfide The generated hydrogen sulfide can react with heavy metal ions Insoluble metal sulfide precipitates are formed, thereby reducing the concentration of soluble iron. Since acidic sulfur-oxidizing bacteria rely on iron and sulfur as metabolic substrates, reducing the availability of these substrates can indirectly inhibit their acidogenic activity.

[0107] Advantages: Sulfur-reducing bacteria grow well under anaerobic or microaerobic conditions, can form a reducing environment in local areas, increase the pH value of the environment, and inhibit acidic sulfur-oxidizing bacteria.

[0108] Disadvantages: Sulfur-reducing bacteria are generally less active in acidic environments, so their growth may be limited in strongly acidic environments. In practical applications, appropriate environmental adjustments may be required to support their growth.

[0109] After a large number of experiments, the present invention selected Desulfovibrio and Desulfovibrio spp., which had the best effect.

[0110] 2. Acidophilic Heterotrophic Bacteria Representative species: Acidophilus Acidiphilium spp. ) and Acidosporium ( Acidocella spp.).

[0111] Mechanism of action: These species are able to grow in extremely acidic environments using organic carbon sources and compete with acidic sulfur-oxidizing bacteria for oxygen and nutrient resources. Although they do not directly inhibit the sulfur oxidation process, they can indirectly inhibit the activity of sulfur-oxidizing bacteria by consuming oxygen in the environment, as acidic sulfur-oxidizing bacteria usually require oxygen for metabolism.

[0112] Advantages: Acidophilic heterotrophs grow well in acidic environments and can use organic matter as a carbon source, competing with sulfur-oxidizing bacteria for environmental resources.

[0113] Disadvantages: Acidophilic heterotrophic bacteria may require an external carbon source to support their growth, and there are few natural carbon sources in the ore leaching environment, so additional carbon sources such as glucose or acetic acid may be required.

[0114] The microbial agents of Examples 1-6 can form a good competition with harmful microorganisms in the mining environment. They can not only effectively neutralize the acidic environment and increase the pH value, but also inhibit the growth and metabolism of harmful microorganisms and reduce the generation of acid, thereby maintaining a relatively stable pH environment, and ultimately achieving the purpose of reducing heavy metal leaching and protecting the ecological environment.

[0115] The present invention discloses a conditioning agent for natural leaching of acid and heavy metals from ores, and relates to the field of soil and mine restoration. The conditioning agent contains microbial agents and lime milk; wherein the microbial agents are aerobic bacteria. The conditioning agent can adjust the pH of the natural acid leaching environment of the ore to form a certain stabilization effect. The added biological agents compete with the acid-producing microorganisms in the original environment, inhibit their metabolism and growth, reduce the production of acid, and maintain the pH environment, thereby achieving a stabilization conditioning effect of weakening the acidic environment and reducing heavy metal leaching.

[0116] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A conditioning agent for reducing ore leaching acid and heavy metals, characterized in that: The conditioning agent contains microbial agent and lime milk. The concentration of the lime milk is 5% to 15%, and the amount of lime milk added is 10% to 30% of the mass of the ore to be conditioned. The microbial agent is sulfur-reducing bacteria or acidophilic heterotrophic bacteria. The solid content of the microbial agent solution is 12% to 25%, and the amount of the microbial agent solution added is 10% to 30% of the mass of the ore to be conditioned.

2. The conditioning agent for reducing ore leaching acid and heavy metals according to claim 1, characterized in that: The microbial agent is composed of sulfur-reducing bacteria or acidophilic heterotrophic bacteria and organic matter, wherein the organic matter includes glucose, auxiliary carbon source and inorganic salt, wherein the mass ratio of glucose, auxiliary carbon source and inorganic salt is 2:3:1; the content of sulfur-reducing bacteria or acidophilic heterotrophic bacteria is 10 7 Up to 10 10 colony forming units.

3. The conditioning agent for reducing ore leaching acid and heavy metals according to claim 2, characterized in that: The auxiliary carbon source is any one or more of glycerol, lactose, and sodium acetate, and the inorganic salt is any one or more of magnesium sulfate, sodium chloride, ammonia water or amino acid, and potassium dihydrogen phosphate.

4. The conditioning agent for reducing ore leaching acid and heavy metals according to claim 1 or 2, characterized in that: The solid content of the microbial agent solution is 17%; the dosage of the microbial agent is 20% of the mass of the ore to be conditioned.

5. The conditioning agent for reducing ore leaching acid and heavy metals according to claim 1, characterized in that: The sulfur-reducing bacteria is any one of Desulfovibrio and Desulfovibrio; the acidophilic heterotrophic bacteria is any one of Acidophilus and Acidosporea.

6. A method for using a conditioning agent for reducing ore leaching acid and heavy metals, characterized in that: The following steps are involved: (1) First, add lime milk to the ore to be conditioned, wherein the concentration of the lime milk is 5% to 15%, and the amount of lime milk added is 10% to 30% of the mass of the ore to be conditioned, so that the pH value is adjusted to 7 to 8; (2) After adding lime milk, re-measure the pH value every 3 to 7 days to ensure that the pH value is maintained between 7 and 8. If the pH value fails to reach 7, continue to add lime milk; (3) After the pH value stabilizes, add microbial agents to the ore. The microbial agents are composed of sulfur-reducing bacteria or acidophilic heterotrophic bacteria and organic matter and are prepared into a solution with a solid content of 12% to 25%. The amount of microbial agent added is 10% to 30% of the mass of the ore to be conditioned.

7. The method for using the conditioning agent for reducing ore leaching acid and heavy metals according to claim 6, characterized in that: In step (3), the sulfur-reducing bacteria is any one of Desulfovibrio and Desulfovibrio.

8. The method for using the conditioning agent for reducing ore leaching acid and heavy metals according to claim 6, characterized in that: In step (3), the acidophilic heterotrophic bacteria is any one of acidophilic bacteria and acidocytophilic bacteria.

9. The method for using the conditioning agent for reducing ore leaching acid and heavy metals according to claim 6 or 7, characterized in that: The solid content of the microbial agent is 17%, and the dosage of the microbial agent is 20% of the mass of the ore to be conditioned.

10. The method for using the conditioning agent for reducing ore leaching acid and heavy metals according to claim 6, characterized in that: In step (3), the microbial agent is prepared by: (1) Cultivate microorganisms under laboratory conditions, collect the cells after they reach the logarithmic growth phase, remove the culture medium by centrifugation or filtration, and retain the wet weight; (2) Mixing glucose, auxiliary carbon source and inorganic salt to prepare a nutrient matrix; (3) Adjust the water content of the nutrient matrix so that when it is subsequently mixed with microorganisms, the overall solid content meets the requirements.

Images