Soilless remediation method for cyanide tailings reservoir

Abstract

The present invention discloses a soilless restoration method for a cyanide tailings reservoir, and relates to the technical field of mine ecological environment restoration and management. The restoration method comprises laying an artificially improved material composed of a bio-based improver, organic fertilizer, and a granulation promoter, Artemisia sphaerocarpa, on the cyanide tailings, spraying a microbial-induced carbonate precipitation agent on the artificial soil layer, sowing grass seeds on the artificially improved cyanide tailings by broadcasting a seed bag formed by mixing grass seeds and microbial agents, combining regular and irregular artificial maintenance, strengthening the germination rate and growth of plants, and restoring the plant coverage of the surface layer of the cyanide tailings reservoir. The present invention adopts a synergistic improvement method of artificially improved materials and functional microorganisms to treat waste with waste, thereby reducing the pH value of the cyanide tailings, stabilizing heavy metal ions, increasing nutrient content and water retention capacity, etc., turning waste into treasure, and improving the cyanide tailings into a "soil-like" matrix suitable for vegetation growth, thereby realizing soilless / low-soil restoration of the cyanide tailings reservoir of the gold mine.

Description

Technical Field

[0001] The present invention relates to the technical fields of mine ecological environment restoration and management and bulk solid waste comprehensive utilization, and in particular to a soilless repair method for a cyanide tailings reservoir. Background Art

[0002] Cyanide tailings are mainly produced by the "gold ore-cyanidation" process of gold-containing oxide ores and a small amount of sulfide ores. Its main elements are Ca, Fe, S, Mg, Si, Al, etc. Some cyanide tailings will contain a small amount of Au, Pb, Zn, Cu, Ag, etc.

[0003] Currently, the treatment and resource utilization of cyanide tailings is a challenge facing nonferrous metals companies. The overall inventory is large, and resource utilization is difficult, primarily due to limitations in transportation conditions, utilization rates, and economic benefits. Most mines use stockpiling to dispose of cyanide tailings, but this faces challenges such as large tailings ponds and limited land acquisition.

[0004] At the same time, current ecological restoration of cyanide tailings ponds mostly relies on soil covering and vegetation restoration. This method is highly applicable and suitable for the ecological restoration of most metal tailings waste sites. However, this ecological restoration method requires a large amount of high-quality soil, which can easily cause secondary ecological damage to the surrounding environment and hinder the sustainable development of the enterprise. Most gold mines face a shortage of imported soil resources, especially in fragile ecological environments and extremely scarce soil resources. The need to purchase soil for restoration has become a serious bottleneck restricting the quality of land reclamation in these areas.

[0005] The particle size of cyanide tailings is similar to that of soil. Under the action of microorganisms, the cyanide in the tailings can be used as the only carbon and nitrogen source for plant growth. The minerals and trace elements in the tailings can provide nutrients for plant growth. After the alkalinity, nutrient composition, aggregate structure, water retention and microecological environment are improved, it can become a potential soil source.

[0006] In the prior art, patent publication number CN115608759A discloses a method for soil-free remediation of tailings ponds by using a bioremediation material prepared with straw as the main raw material, combined with organic materials and a biocomposite bacterial agent, to improve the soil of cyanide tailings. The improved cyanide tailings are used to replace "guest soil". However, this technology mainly regulates the alkalinity, nutrient content, water retention capacity and porosity of the cyanide tailings, and does not pay attention to the toxic and inhibitory effects of heavy metals in the cyanide tailings on plants and microorganisms.

[0007] Patent publication number CN107971335A discloses a method for phytoremediation of cyanide residues in the gold industry. This patent primarily addresses phytoremediation of cyanide residues by adding nutrients and chemicals, supplemented by the use of salt- and alkali-tolerant plants. While focusing on physical and chemical improvements to nutrients, cyanide content, and pH, it fails to consider the impact of microecological environment improvements on plant growth.

[0008] In view of this, it is necessary to design an improved soilless remediation method for cyanide tailings reservoir to solve the above problems. Summary of the Invention

[0009] In response to the shortcomings of the above-mentioned prior art, the present invention aims to provide a soilless remediation method for cyanide tailings reservoirs. This method, based on the practical application of gold mining and adhering to the concept of "transforming waste into treasure," uses the large amount of cyanide tailings produced by the gold industry's cyanidation process as the primary raw material. Microbial-induced carbonate precipitation (MICP) bacteria are introduced to co-precipitate with heavy metals in the tailings, immobilizing heavy metals such as As, Cu, Pb, Cd, Cr, and Hg, thereby reducing their bioavailability. Artemisia sphaerosa gum is used as a granulation promoter, which is combined with a bio-based amendment and organic fertilizer in a specific ratio to form an artificially improved material. Artemisia sphaerosa gum has extremely strong water absorption and swelling capabilities, forming a strong, connective gel in aqueous solution with good water retention. This facilitates the growth and reproduction of functional bacteria, microbial-induced carbonate precipitation (MICP) bacteria, further promoting the solidification of heavy metals in cyanide tailings and enhancing the biodiversity of the tailings.

[0010] This remediation method improves the physical, chemical, and soil biological properties of cyanide tailings to produce an artificial soil based on the improved cyanide tailings. The soilless ecological restoration of cyanide tailings ponds in gold mines can achieve comprehensive benefits such as improving the mine environment, protecting precious soil resources, reducing solid waste storage, and improving the utilization rate of bulk solid waste resources.

[0011] This restoration method uses artificially improved materials and functional microorganisms to synergistically improve the waste, using waste to treat waste. It has the effects of reducing the pH of cyanide tailings, stabilizing heavy metal ions, and increasing nutrient content and water retention capacity, turning waste into treasure, and improving cyanide tailings into a "soil-like" matrix suitable for vegetation growth, thus realizing soilless / low-soil restoration of gold mine cyanide tailings reservoirs.

[0012] To achieve the above object, the present invention provides a soilless remediation method for a cyanide tailings reservoir, comprising the following steps:

[0013] S1: Level the cyanide tailings reservoir and plow and loosen the top 30 cm thick tailings.

[0014] S2, evenly spread the artificially improved materials on the surface of the cyanide tailings reservoir, mix and level them with the surface tailings to form an artificial soil layer with a thickness of 40 to 50 cm, and then pile them for 7 to 14 days;

[0015] The artificial improvement material consists of a bio-based improver, organic fertilizer and a pelletizing promoter;

[0016] The bio-based improver is the product of agricultural waste that has been pulverized, expanded, and aerobically composted for 15 to 60 days;

[0017] The organic fertilizer is one or a mixture of fermented cattle and sheep manure, pig manure, chicken and duck manure, domestic sewage sludge, and compound fertilizer;

[0018] The granulation promoter is Artemisia sphaerocarpa gum, which is mainly composed of glucose, galactose, mannose, arabinose and xylose;

[0019] S3, spray the bacterial solution on the artificial soil layer, with a spraying volume of 2~5L / m 2 , in order to further improve the above-mentioned cyanide tailings reservoir;

[0020] The bacterial solution is composed of a functional bacterial agent and a culture medium; the functional bacterial agent is a microbial induced carbonate precipitating bacteria; the main components of the culture medium are urea, calcium chloride and water; the microbial induced carbonate precipitating (MICP) bacteria forms a co-precipitation with heavy metals in the tailings, fixes heavy metals such as As, Cu, Pb, Cd, Cr, and Hg in the tailings, and reduces the bioavailability of heavy metals in the tailings;

[0021] S4, curing the cyanide tailings further artificially improved in step S3 by sprinkling water, maintaining the moisture content of the improved substrate at 23-28%, sprinkling water at a frequency of 1-2 days / time, and a curing period of 7 days;

[0022] S5: Sowing grass seeds in a mixed sowing method on the artificially modified cyanide tailings, combined with regular and irregular manual maintenance, to enhance plant germination rate and growth, and restore plant cover on the surface of the cyanide tailings reservoir;

[0023] The mixed sowing material consists of mixed grass seeds and microbial agents; the mass ratio of the mixed grass seeds to the microbial agent is (5-10):1; the microbial agent contains Bacillus subtilis, Trichoderma, actinomycetes, potassium humate, and vitamins; and the mixed grass seeds include seeds of ryegrass, tall fescue, bermudagrass, alfalfa, and sesbania.

[0024] As a further improvement of the present invention, in step S2, the artificially modified material comprises a bio-based modifying agent, organic fertilizer, and artemisia gum in a mass ratio of (5-10):(1-5):(0.2-0.4). Artemisia gum has a strong ability to absorb and swell, forming a strong, connective gel in aqueous solution. It has excellent water retention and is beneficial for the growth and reproduction of functional microbial induced carbonate precipitation (MICP) bacteria, further promoting the solidification of heavy metals in cyanide residue and enhancing the biodiversity of the residue.

[0025] As a further improvement of the present invention, in step S3, the mass ratio of the microbial-induced carbonate-precipitating bacteria to the culture medium is 1:(1-2).

[0026] As a further improvement of the present invention, in step S2, the mass ratio of the cyanide tailings to the artificially modified material is 100:(5-10).

[0027] As a further improvement of the present invention, in step S1, the cyanide tailings that meet the requirements are tailings produced by the gold cyanidation process, with a pH of 8.0-9.5, the mass of particles with a particle size greater than 0.075 mm does not exceed 20% of the total mass, the main components are SiO2, Al2O3, and Fe2O3, the cyanide content is less than 300 mg / kg, and the moisture content is not more than 20%.

[0028] As a further improvement of the present invention, in step S2, the bio-based modifier has a dark brown appearance, a particle size of ≤1 mm, a pH of 6.5-7.0, and a specific gravity of 0.6-0.7 g / cm 3 , organic matter content ≥45% (dry basis), nutrient (N, P, K) content ≥3%, humic acid content ≥20%.

[0029] As a further improvement of the present invention, in step S5, the microbial agent comprises the following components in parts by weight: 30-50 parts by weight of Bacillus subtilis, 20-30 parts by weight of Trichoderma, 20-30 parts by weight of actinomycetes, 5-10 parts by weight of potassium fulvate, and 2-5 parts by weight of vitamins, and the number of viable bacteria is ≥50 billion / g.

[0030] As a further improvement of the present invention, in step S5, the mixed grass seeds contain the following components in parts by weight: 10-20 parts of ryegrass, 10-20 parts of tall fescue, 20-30 parts of bermudagrass, 10-20 parts of alfalfa and 5-10 parts of sesbania.

[0031] As a further improvement of the present invention, the agricultural waste includes one or more of corn straw, rice husk, and sugarcane bagasse.

[0032] The beneficial effects of the present invention are:

[0033] The present invention is based on the actual situation of non-ferrous mines and adheres to the concept of "turning waste into treasure". The method is based on the actual situation of gold mines and adheres to the concept of "turning waste into treasure". A large amount of cyanide tailings produced by the cyanidation process of the gold industry is used as the main raw material. Artemisia sphaerosa gum is selected as a granulation promoter. It is mixed with a bio-based modifier and an organic fertilizer in a specific proportion to form an artificial improvement material. Microbial induced carbonate precipitating (MICP) bacteria are introduced. The microbial induced carbonate precipitating (MICP) bacteria form a co-precipitation with heavy metals in the tailings, fix heavy metals such as As, Cu, Pb, Cd, Cr, and Hg in the tailings, reduce the bioavailability of heavy metals in the tailings, improve the microecological environment of the cyanide tailings, and utilize the growth of plants and microorganisms. Artemisia sphaerosa gum has extremely strong water absorption and swelling ability, can form a strong connective gel in an aqueous solution, has good water retention, is conducive to the growth and reproduction of functional bacteria microbial induced carbonate precipitating (MICP) bacteria, further promotes the solidification of heavy metals in the cyanide tailings and improves the biodiversity in the cyanide tailings.

[0034] This remediation method improves the physical, chemical, and soil biological properties of cyanide tailings to produce an artificial soil based on the improved cyanide tailings. The soilless ecological restoration of cyanide tailings ponds in gold mines can achieve comprehensive benefits such as improving the mine environment, protecting precious soil resources, reducing solid waste storage, and improving the utilization rate of bulk solid waste resources.

[0035] Specifically, in the present invention, the pH of the bio-based amendment is 6.5-7.0, and the humic acid content is ≥20%, which can effectively improve the alkalinity of the cyanide tailings so that the pH value meets the growth requirements of plants and microorganisms; the bio-based amendment has a high fluffiness and a low specific gravity, which can improve the air permeability and water retention capacity of the improved cyanide tailings; on the other hand, the organic matter content in the bio-based amendment is ≥45%, and the nutrient content (N, P, K) is ≥3%, which can effectively improve the fertility of the improved cyanide tailings and promote vegetation growth.

[0036] This restoration method mixes grass seeds with microbial agents to form seed packages. The microbial agents in the seed packages, such as Bacillus subtilis, Trichoderma, and Actinomycetes, have the functions of inhibiting pathogens, promoting plant growth, and enhancing plant resistance. At the same time, they improve soil structure, prevent soil compaction, and enhance soil fertility.

[0037] In addition, Bacillus subtilis, Trichoderma, actinomycetes, potassium humate, vitamins, etc. in microbial agents can regulate the nutrient content in tailings, promote the formation of soil aggregate structure, decompose residual mineral processing agents in tailings, change the structure of soil microbial flora, enhance the resistance of vegetation, and promote the transformation of cyanide tailings into a "soil-like" matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The vegetation growth diagram of Examples 1-3 and unimproved cyanide slag.

[0039] Figure 2 This is the vegetation growth graph of Example 1 after the vegetation has grown for 60 days.

[0040] Figure 3 This is the vegetation growth graph of Example 4 after the vegetation has grown for 60 days.

[0041] Figure 4 This is the vegetation growth diagram of the vegetation in Comparative Example 1 after 60 days of growth.

[0042] Figure 5 This is the vegetation growth diagram of Comparative Example 2 after the vegetation has grown for 60 days.

[0043] Figure 6 This is the vegetation growth diagram of Comparative Example 4 after the vegetation has grown for 60 days.

[0044] Figure 7 This is the vegetation growth diagram of Comparative Example 5 after the vegetation has grown for 60 days.

[0045] Figure 8 This is the vegetation growth diagram of Comparative Example 6 after the vegetation has grown for 60 days. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] It should also be noted here that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0048] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0049] The present invention provides a soilless remediation method for a cyanide tailings reservoir, comprising the following steps:

[0050] S1, level the cyanide tailings reservoir and plow and loosen the top 30 cm thick tailings;

[0051] Among them, the cyanide tailings are tailings produced by the gold cyanidation process, with a pH of 8.0~9.5, the mass of particles with a particle size greater than 0.075mm does not exceed 20% of the total mass, the main components are SiO2, Al2O3, Fe2O3, the cyanide content is less than 300mg / kg, and the water content is not more than 20%.

[0052] S2, evenly spread the artificially modified materials on the surface of the cyanide tailings reservoir, mix and level them with the surface tailings to form an artificial soil layer with a thickness of 40 to 50 cm, and then pile them for 7 to 14 days; the mass ratio of cyanide tailings to artificially modified materials is 100: (5 to 10).

[0053] Specifically, the artificial improvement material consists of a bio-based improver, an organic fertilizer, and a granulation promoter in a mass ratio of (5~10): (1~5): (0.2~0.4).

[0054] Bio-based amendments are made from agricultural waste such as corn stalks, rice husks, and sugarcane bagasse, which has been pulverized, expanded, and aerobically composted for 15 to 60 days. The bio-based amendments are dark brown in appearance, with a particle size of ≤1 mm, a pH of 6.5 to 7.0, and a specific gravity of 0.6 to 0.7 g / cm. 3 , calculated on a dry basis, the organic matter content is ≥45%, the nutrient content is ≥3%, and the humic acid content is ≥20%.

[0055] Organic fertilizer is a mixture of one or more of fermented cattle and sheep manure, pig manure, chicken and duck manure, domestic sewage sludge, and compound fertilizer;

[0056] The granulation promoter is Artemisia sphaerocarpa gum, which is mainly composed of glucose, galactose, mannose, arabinose, xylose, etc.

[0057] S3, spray the bacterial solution on the artificial soil layer, with a spraying volume of 2~5L / m 2 , in order to further improve the above-mentioned cyanide tailings reservoir;

[0058] The bacterial solution consists of a functional bacterial agent and a culture medium. The functional bacterial agent is a microbial carbonate-precipitating bacterium; the main components of the culture medium are urea, calcium chloride, and water; the mass ratio of the microbial carbonate-precipitating bacterium to the culture medium is 1:(1-2).

[0059] S4, curing the cyanide tailings further artificially improved in step S3 by sprinkling water, maintaining the moisture content of the improved substrate at 23-28%, sprinkling water at a frequency of 1-2 days / time, and a curing period of 7 days;

[0060] S5: Sowing grass seeds in a mixed sowing method on the artificially modified cyanide tailings, combined with regular and irregular manual maintenance, to enhance plant germination rate and growth, and restore plant cover on the surface of the cyanide tailings reservoir;

[0061] The mixed sowing material consists of mixed grass seeds and microbial agents; the mass ratio of the mixed grass seeds to the microbial agents is (5-10):1; the microbial agents contain Bacillus subtilis, Trichoderma, actinomycetes, potassium humate, and vitamins; the mixed grass seeds include seeds of ryegrass, tall fescue, bermudagrass, alfalfa, and sesbania.

[0062] Specifically, the microbial agent contains the following components in parts by weight: 30-50 parts by weight of Bacillus subtilis, 20-30 parts by weight of Trichoderma, 20-30 parts by weight of actinomycetes, 5-10 parts by weight of potassium fulvic acid, and 2-5 parts by weight of vitamins, and the number of viable bacteria is ≥50 billion / gram.

[0063] Microbial agents such as Bacillus subtilis, Trichoderma, and actinomycetes have the functions of inhibiting pathogens, promoting plant growth, and enhancing plant resistance. At the same time, they can improve soil structure, prevent soil compaction, and enhance soil fertility.

[0064] Specifically, the mixed grass seeds contain the following components in parts by weight: 10-20 parts of ryegrass, 10-20 parts of tall fescue, 20-30 parts of bermudagrass, 10-20 parts of alfalfa and 5-10 parts of sesbania.

[0065] The soilless remediation method for cyanide tailings reservoir provided by the present invention is described below with reference to specific examples. Unless otherwise specified, the raw materials and reagents in the examples of this application were purchased through commercial channels.

[0066] Example 1

[0067] This embodiment provides a soilless remediation method for a cyanide tailings reservoir. The cyanide tailings produced by a gold production enterprise in Inner Mongolia are used. The main chemical components of the cyanide tailings are shown in Table 1.

[0068] S1: Level the cyanide tailings reservoir and plow and loosen the top 30cm thick tailings.

[0069] S2, evenly laying the artificially modified material on the surface of the cyanide tailings in a mass ratio of 100:10, mixing and leveling with a rotary tiller, and naturally stacking for 7 days;

[0070] Among them, artificial improvement materials are composed of bio-based improvers, organic fertilizers and pellet promoter Artemisia sphaerocarpa gum;

[0071] Bio-based amendments are the product of agricultural waste that has been pulverized, expanded, and aerobically composted for 15 days;

[0072] Organic fertilizer is a mixture of fermented cattle and sheep manure, pig manure, chicken and duck manure, domestic sewage sludge, and compound fertilizer;

[0073] The granulation promoter is Artemisia sphaerocarpa gum, which is mainly composed of glucose, galactose, mannose, arabinose, xylose, etc. The specific proportions of each component are shown in Table 2 (corresponding to 1# improved cyanide residue);

[0074] S3, on the modified cyanide slag at 5L / m 2 Spraying a bacterial solution to further artificially improve the cyanide tailings reservoir. The bacterial solution consists of functional microbial agents, microorganisms that induce carbonate precipitation, and a culture medium, the main components of which are urea, calcium chloride, and water.

[0075] The mass ratio of microbial induced carbonate precipitating bacteria to culture medium was 1:1.

[0076] S4, curing the cyanide tailings further artificially improved in step S3 by sprinkling water for 7 days, maintaining the moisture content of the improved substrate at 25%, and sprinkling water once a day;

[0077] S5, adopt mixed sowing method to sow grass seeds and carry out manual maintenance regularly.

[0078] The mixed sowing material is composed of mixed grass seeds and a microbial agent. Specifically, the microbial agent contains the following components by weight: 40 parts by weight of Bacillus subtilis, 30 parts by weight of Trichoderma, 20 parts by weight of actinomycetes, 5 parts by weight of potassium fulvate, and 5 parts by weight of vitamins, with a viable cell count of ≥50 billion / gram.

[0079] The mixed grass seeds contain the following components in parts by weight: 20 parts of ryegrass, 20 parts of tall fescue, 30 parts of bermudagrass, 20 parts of alfalfa and 10 parts of sesbania.

[0080] Example 2-3

[0081] Compared to Example 1, Examples 2-3 differ in that the ratios of the components in the artificially modified material in Step S2 are changed, as shown in Table 2 (corresponding to modified cyanide slag #2 and modified cyanide slag #3, respectively). The remaining steps are generally the same as in Example 1 and are not further described here.

[0082] By adding the materials in the proportions shown in Table 2, the physical and chemical properties and microecological environment of the cyanide tailings were improved to form a "soil-like" matrix that meets the physical and chemical properties and nutrients required for plant growth. The physical and chemical parameter results of the improved cyanide tailings in Examples 1-3 are shown in Table 3. The mixed grass seeds were sown and artificial maintenance was carried out regularly. The vegetation grew well. Figure 1 shown.

[0083] Table 1 Main chemical components of cyanide tailings before improvement

[0084]

[0085] Table 2 Improved material ratio

[0086]

[0087] Table 3 Physical and chemical parameters of improved cyanide tailings

[0088]

[0089] Table 3 shows that the organic matter, ammonium nitrogen, available phosphorus, and available potassium content of each group under the different improvement schemes increased to a certain extent compared to the unimproved original residue. Specifically, the organic matter content of the improved cyanide residue reached "extremely abundant" levels, ammonium nitrogen reached "upper-medium to abundant" levels, available phosphorus reached "upper-medium" levels, and available potassium reached "extremely abundant" levels. Simultaneously, the pH values decreased to a certain extent, from alkaline to neutral, making it more suitable for vegetation growth.

[0090] Figure 1 The vegetation growth diagram of Examples 1-3 and unimproved cyanide slag.

[0091] It can be seen that the unmodified cyanide tailings had severe compaction due to its high alkalinity and no vegetation grew. The vegetation began to germinate one week after the seeds of the three groups of modified cyanide tailings were sown, and after 30 days, the plants in each group grew well.

[0092] Figure 2 This is a 60-day vegetation growth graph of the vegetation in Example 1. It can be seen that within 60 days, the vegetation grew well.

[0093] Example 4

[0094] This example provides a soilless remediation method for a cyanide tailings reservoir. Compared to Example 1, Example 4 differs in that a different cyanide tailings reservoir is used. Example 4 improves the cyanide tailings reservoir of a gold production enterprise in Guangxi. The main chemical components of the improved cyanide tailings are shown in Table 4. The remaining components are generally the same as in Example 1 and are not further described here.

[0095] Table 4 Main chemical components of cyanide tailings before improvement

[0096]

[0097] Figure 3 This is a 60-day vegetation growth graph of the vegetation in Example 4. It can be seen that within 60 days, the vegetation grew well and the coverage reached more than 90%.

[0098] Comparative Example 1

[0099] The main difference between Comparative Example 1 and Example 1 is that in step S2, no bio-based modifier is added to the artificially modified material. The other steps are substantially the same as those in Example 1 and will not be described in detail here.

[0100] Observe the vegetation growth and the results are as follows Figure 4 As shown, it can be seen that within 60 days, the vegetation germination rate is low, the plants are short and the growth is poor.

[0101] Comparative Example 2

[0102] Compared with Example 1, the main difference of Comparative Example 2 is that in step S2, the granulation promoter Artemisia sphaerocarpa glue is not added to the artificially improved material. The rest is basically the same as Example 1 and will not be repeated here.

[0103] Observe the vegetation growth and the results are as follows Figure 5 As shown, it can be seen that within 60 days, the cyanide tailings without artemisia glue had poor water retention, low vegetation germination rate, and slow growth.

[0104] Comparative Example 3

[0105] Compared with Example 1, the main difference of Comparative Example 3 is that in step S2, the granulation promoter artemisia gum is replaced by polyacrylamide. The rest is basically the same as Example 1 and will not be repeated here.

[0106] Observation of the vegetation growth showed that after adding the polyacrylamide water-retaining agent, the cyanide tailings had a certain water-retaining capacity and the vegetation grew well, but the vegetation height and leaf chlorophyll content were lower than those in Example 1, indicating that Artemisia sphaerocarpa gum not only improved the aggregate structure and water-retaining capacity of the cyanide tailings, but also synergistically promoted the growth and reproduction of beneficial functional microorganisms, further promoting vegetation growth.

[0107] Comparative Example 4

[0108] Compared with Example 4, Comparative Example 4 is different in that: no microbial-induced carbonate precipitation bacterial solution is sprayed, specifically: step S3 is not performed. Other differences are generally the same as Example 4 and are not repeated here.

[0109] Observe the vegetation growth and the results are as follows Figure 6 As shown, it can be seen that within 60 days, the plant coverage is lower than that in Example 4, and the plant height is lower, indicating that the functional bacterial solution was not sprayed and the heavy metals in the cyanide residue have a certain inhibitory effect on vegetation.

[0110] Comparative Example 5

[0111] Compared with Example 4, the main difference of Comparative Example 5 is that in step S5, the mixed sowing material only contains mixed grass seeds, and no microbial agent is added to form the seed bag. The rest is basically the same as Example 4 and will not be repeated here.

[0112] Observe the vegetation growth and the results are as follows Figure 7As shown, it can be seen that within 60 days, the vegetation coverage is good, but the plant height is lower than that in Example 4, indicating that the microbial agent in the seed packet can enhance plant resistance and promote plant growth.

[0113] Comparative Example 6

[0114] Compared with Example 4, the main difference is that in Example 4, an unimproved area of the tailings pond is selected for sowing mixed grass seeds. The rest is basically the same as Example 4 and will not be repeated here.

[0115] Observe the vegetation growth and the results are as follows Figure 8 As shown, it can be seen that within 60 days, the vegetation in the unimproved cyanide residue germinated and withered, and no vegetation grew.

[0116] The above describes the preferred embodiments of the present invention. However, the scope of protection of the present invention is not limited to the specific details of the above embodiments. Within the technical concept of the present invention, any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention. These simple variations all fall within the scope of protection of the present invention.

[0117] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0118] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A soilless remediation method for a cyanide tailings reservoir, characterized by: The steps include: S1: Level the cyanide tailings reservoir and plow and loosen the top 30 cm thick tailings. S2, evenly spread the artificially improved materials on the surface of the cyanide tailings reservoir, mix and level them with the surface tailings to form an artificial soil layer with a thickness of 40 to 50 cm, and then pile them for 7 to 14 days; The artificial improvement material consists of a bio-based improver, organic fertilizer and a pelletizing promoter; The bio-based improver is the product of agricultural waste that has been pulverized, expanded, and aerobically composted for 15 to 60 days; The organic fertilizer is one or a mixture of fermented cattle and sheep manure, pig manure, chicken and duck manure, domestic sewage sludge, and compound fertilizer; The granulation promoter is Artemisia sphaerocephala gum, which is mainly composed of glucose, galactose, mannose, arabinose, and xylose; the artificial improvement material is composed of bio-based improver, organic fertilizer and Artemisia sphaerocephala gum in a mass ratio of (5-10): (1-5): (0.2-0.4); S3, spray the bacterial solution on the artificial soil layer, with a spraying volume of 2~5L / m 2 , in order to further improve the above-mentioned cyanide tailings reservoir; The bacterial solution is composed of a functional bacterial agent and a culture medium; the functional bacterial agent is a microbial-induced carbonate precipitating bacterium; the main components of the culture medium are urea, calcium chloride and water; S4, curing the cyanide tailings further artificially improved in step S3 by sprinkling water, maintaining the moisture content of the improved substrate at 23-28%, sprinkling water at a frequency of 1-2 days / time, and a curing period of 7 days; S5: Sowing grass seeds in a mixed sowing method on the artificially modified cyanide tailings, combined with regular and irregular manual maintenance, to enhance plant germination rate and growth, and restore plant cover on the surface of the cyanide tailings reservoir; The mixed sowing material consists of mixed grass seeds and microbial agents; the mass ratio of the mixed grass seeds to the microbial agent is (5-10):1; the microbial agent contains Bacillus subtilis, Trichoderma, actinomycetes, potassium humate, and vitamins; and the mixed grass seeds include seeds of ryegrass, tall fescue, bermudagrass, alfalfa, and sesbania.

2. The soilless remediation method for a cyanide tailings reservoir according to claim 1, wherein: The mass ratio of the microbial inducing carbonate precipitating bacteria to the culture medium is 1:(1-2).

3. The soilless remediation method for a cyanide tailings reservoir according to claim 1, wherein: In step S2, the mass ratio of the cyanide tailings to the artificially modified material is 100:(5-10).

4. The soilless remediation method for a cyanide tailings reservoir according to claim 1, wherein: In step S1, the cyanide tailings are tailings produced by the gold cyanidation process, with a pH of 8.0-9.5, a mass of particles with a particle size greater than 0.075 mm not exceeding 20% of the total mass, main components of which are SiO2, Al2O3, and Fe2O3, a cyanide content of less than 300 mg / kg, and a moisture content of no more than 20%.

5. The soilless remediation method for a cyanide tailings reservoir according to claim 1, wherein: In step S2, the bio-based modifier has a dark brown appearance, a particle size of ≤1 mm, a pH of 6.5-7.0, and a specific gravity of 0.6-0.7 g / cm 3 , calculated on a dry basis, the organic matter content is ≥45%, the nutrient content is ≥3%, and the humic acid content is ≥20%.

6. The soilless remediation method for a cyanide tailings dam according to claim 1, characterized in that: In step S5, the microbial agent comprises the following components in parts by weight: 30-50 parts by weight of Bacillus subtilis, 20-30 parts by weight of Trichoderma, 20-30 parts by weight of actinomycetes, 5-10 parts by weight of potassium fulvate, and 2-5 parts by weight of vitamins, with a viable cell count of ≥50 billion / g.

7. The soilless remediation method for a cyanide tailings reservoir according to claim 1, wherein: In step S5, the mixed grass seeds contain the following components in parts by weight: 10-20 parts of ryegrass, 10-20 parts of tall fescue, 20-30 parts of bermudagrass, 10-20 parts of alfalfa and 5-10 parts of sesbania.

8. The soilless remediation method for a cyanide tailings reservoir according to claim 1, wherein: The agricultural waste includes one or more of corn straw, rice husk, and sugarcane bagasse.

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