Soilless remediation method for cyanidation tailing warehouse

Abstract

The invention discloses a soilless restoration method for a cyanidation tailing reservoir, and relates to the technical field of mine ecological environment restoration and treatment. The remediation method comprises the following steps: laying an artificial improvement material composed of a bio-based modifier, an organic fertilizer and an aggregate accelerator sa-hao seed gum on the cyanidation tailings, and spraying a microbial induced carbonate precipitation bacterial agent on an artificial soil layer, grass seeds are sown on the artificially improved cyanidation tailings in a broadcast sowing mode that mixed grass seeds and microbial agents form seed bags, regular and irregular artificial maintenance is combined, the germination rate and growth vigor of plants are enhanced, and plant covering on the surface layer of a cyanidation tailings library is restored. According to the method, an artificial improvement material and functional microorganism synergistic improvement mode is adopted, waste is treated with waste, the effects of reducing the pH value of the cyanidation tailings, stabilizing heavy metal ions, improving the nutrient content and the water retention capacity and the like are achieved, waste is turned into wealth, the cyanidation tailings are improved into a soil-like matrix suitable for vegetation growth, and the vegetation quality is improved. And soil-free / less-soil repairing of the gold mine cyanidation tailing warehouse is achieved.

Description

Technical Field

[0001] The 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] At present, the treatment and resource utilization of cyanide tailings are problems faced by non-ferrous metal enterprises. The overall stock is large and resource utilization is difficult, mainly due to the limitations of transportation conditions, utilization level and economic benefits. Most mines use the stockpiling method to dispose of cyanide tailings, but they face difficulties such as large tailings ponds and tight land acquisition.

[0004] At the same time, the current ecological restoration of cyanide tailings ponds mostly adopts the method of covering with vegetation. This method is highly applicable and suitable for the ecological restoration of most metal tailings wastelands. However, this ecological restoration method first requires the consumption of a large amount of high-quality soil sources, which is easy to cause secondary ecological damage to the surrounding environment and is not conducive to the sustainable development of enterprises. Most gold mines have the problem of shortage of "foreign soil" resources, especially the fragile ecological environment and extremely scarce soil resources. The need to purchase soil for restoration has become a serious bottleneck restricting the quality of land reclamation in the region.

[0005] The particle size of cyanide tailings is similar to that of soil. The cyanide in the tailings can be used as the only carbon and nitrogen source for plant growth under the action of microorganisms. 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, the patent with publication number CN115608759A discloses a method for soil-free restoration of tailings ponds by using a bioremediation material prepared with straw as the main raw material combined with organic materials and biological composite bacterial agents to improve cyanide tailings. However, this technology mainly adjusts the alkalinity, nutrient content, water retention capacity and looseness 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. The patent mainly improves cyanide residues by adding nutrients and chemical agents, and uses salt-alkali-tolerant plants to phytoremediate cyanide residues. It focuses on the physical and chemical improvement of nutrients, cyanide content and pH, but fails to pay attention to the impact of microecological environment improvement on plant growth.

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

[0009] In view of the defects of the above-mentioned prior art, the purpose of the present invention is to provide a soilless restoration method for cyanide tailings reservoir. The method starts from the actual situation of gold mines, adheres to the concept of "turning waste into treasure", takes a large amount of cyanide tailings produced by the cyanidation process of the gold industry as the main raw material, introduces microbial induced carbonate precipitation (MICP) bacteria, and forms co-precipitation with heavy metals in the tailings to fix heavy metals such as As, Cu, Pb, Cd, Cr, Hg in the tailings, and reduce the bioavailability of heavy metals in the tailings; Artemisia sphaerocephala gum is selected as a granulation promoter, and is mixed with bio-based modifiers and organic fertilizers in a specific proportion to form an artificial improvement material. Artemisia sphaerocephala gum has a strong ability to absorb and swell, and 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 precipitation (MICP) bacteria, and further promotes the solidification of heavy metals in cyanide slag and improves the biodiversity in cyanide slag.

[0010] This restoration method improves the physical, chemical and soil biological properties of cyanide tailings to produce an artificial soil based on the improvement of cyanide tailings, which is used for soilless ecological restoration of cyanide tailings ponds in gold mines, achieving 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 waste, which reduces the pH value of cyanide tailings, stabilizes heavy metal ions, increases nutrient content and water retention capacity, and turns waste into treasure. It improves cyanide tailings into a "soil-like" matrix suitable for vegetation growth, thereby achieving soilless / low-soil restoration of gold mine cyanide tailings storage facilities.

[0012] To achieve the above object, the present invention provides a soilless remediation method for a cyanide tailings silo, comprising the following steps: S1, level the cyanide tailings reservoir and till and loosen the 30 cm thick tailings on the surface; 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, an organic fertilizer and a pelletizing promoter; The bio-based improver is the product of agricultural waste after being pulverized, expanded, and aerobic 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; S3, spraying bacterial solution on the artificial soil layer, the amount of bacterial solution spraying is 2~5L / m 2 , in order to further improve the above-mentioned cyanide tailings reservoir artificially; 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 to fix heavy metals such as As, Cu, Pb, Cd, Cr, Hg in the tailings, thereby reducing the bioavailability of heavy metals in the tailings; S4, watering and curing the cyanide tailings further artificially improved in step S3, maintaining the moisture content of the improved matrix at 23-28%, with a watering frequency of 1-2 days / time and a curing period of 7 days; S5, using mixed sowing method to sow grass seeds on artificially improved cyanide tailings, combined with regular and irregular artificial maintenance, to enhance the germination rate and growth of plants, and restore the plant coverage 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.

[0013] As a further improvement of the present invention, in step S2, the artificial improvement material is composed of a bio-based improver, an organic fertilizer and wormwood gum in a mass ratio of (5-10): (1-5): (0.2-0.4). The wormwood gum has a strong ability to absorb and swell, can form a strong connective gel in an aqueous solution, has good water retention, and is conducive to the growth and reproduction of functional bacteria microbial induced carbonate precipitation (MICP) bacteria, further promoting the solidification of heavy metals in cyanide slag and improving the biodiversity in cyanide slag.

[0014] As a further improvement of the present invention, in step S3, the mass ratio of the microbial inducing carbonate precipitating bacteria to the culture medium is 1:(1-2).

[0015] As a further improvement of the present invention, in step S2, the mass ratio of the cyanidation tailings to the artificially modified material is 100:(5-10).

[0016] 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, a mass of particles with a particle size greater than 0.075 mm not exceeding 20% ​​of the total mass, main components being SiO2, Al2O3, and Fe2O3, a cyanide content of less than 300 mg / kg, and a water content of no more than 20%.

[0017] 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% (on a dry basis), nutrient content (N, P, K) ≥3%, and humic acid content ≥20%.

[0018] 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 humate, and 2-5 parts by weight of vitamins, and the number of viable bacteria is ≥50 billion / g.

[0019] 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.

[0020] As a further improvement of the present invention, the agricultural waste includes one or more of corn stalks, rice husks, and sugarcane bagasse.

[0021] The beneficial effects of the present invention are: The invention is based on the actual situation of nonferrous 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 cyanidation tailings produced by the cyanidation process of the gold industry is used as the main raw material, and artemisia gum is selected as a pellet promoter. It is mixed with a bio-based improver and an organic fertilizer in a specific proportion to form an artificial improvement material, and microbial induced carbonate precipitation (MICP) bacteria are introduced. The microbial induced carbonate precipitation (MICP) bacteria and heavy metals in the tailings form a co-precipitation, fix As, Cu, Pb, Cd, Cr, Hg and other heavy metals in the tailings, reduce the bioavailability of heavy metals in the tailings, improve the microecological environment of the cyanidation tailings, and utilize plants and microorganisms for growth. Artemisia 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 precipitation (MICP) bacteria, further promotes the solidification of heavy metals in the cyanidation slag and improves the biodiversity in the cyanidation slag.

[0022] This restoration method improves the physical, chemical and soil biological properties of cyanide tailings to produce an artificial soil based on the improvement of cyanide tailings, which is used for soilless ecological restoration of cyanide tailings ponds in gold mines, achieving 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.

[0023] Specifically, in the present invention, the pH of the bio-based modifier 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 modifier has a high fluffiness and a small specific gravity, and 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 modifier 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.

[0024] 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.

[0025] In addition, Bacillus subtilis, Trichoderma, actinomycetes, potassium humate, vitamins, etc. in microbial agents can regulate the nutrient content in the tailings, promote the formation of soil aggregate structure, decompose residual mineral processing agents in the 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

[0026] Figure 1 The vegetation growth diagram of Examples 1-3 and unimproved cyanide slag.

[0027] Figure 2 This is the vegetation growth graph of Example 1 after the vegetation has grown for 60 days.

[0028] Figure 3 This is the vegetation growth graph of Example 4 after the vegetation has grown for 60 days.

[0029] Figure 4 This is the vegetation growth diagram of the vegetation in Comparative Example 1 after 60 days of growth.

[0030] Figure 5 This is the vegetation growth diagram of the vegetation in Comparative Example 2 after 60 days of growth.

[0031] Figure 6 This is the vegetation growth diagram of Comparative Example 4 after the vegetation has grown for 60 days.

[0032] Figure 7 This is the vegetation growth diagram of the vegetation in Comparative Example 5 after 60 days of growth.

[0033] Figure 8 This is the vegetation growth diagram of Comparative Example 6 after the vegetation has grown for 60 days. DETAILED DESCRIPTION

[0034] In order to make the purpose, 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.

[0035] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0036] 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 other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0037] The present invention provides a soilless repair method for a cyanide tailings silo, comprising the following steps: S1, level the cyanide tailings reservoir and till and loosen the 30 cm thick tailings on the surface; Among them, the cyanide tailings are the 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%.

[0038] S2, evenly spread the artificial improvement 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; among them, the mass ratio of cyanide tailings to artificial improvement materials is 100: (5 to 10).

[0039] 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).

[0040] Bio-based improver is the product of corn stalks, rice husks, sugarcane bagasse and other agricultural wastes after pulverization, puffing and aerobic composting for 15 to 60 days. The appearance of bio-based improver is dark brown, the particle size is ≤1 mm, the pH is 6.5~7.0, and the specific gravity is 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%.

[0041] 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; The granulation promoter is Artemisia sphaerocephala gum, which is mainly composed of glucose, galactose, mannose, arabinose, xylose, etc. S3, spraying bacterial solution on the artificial soil layer, the amount of bacterial solution spraying is 2~5L / m 2 , in order to further improve the above-mentioned cyanide tailings reservoir artificially; 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; wherein the mass ratio of the microbial induced carbonate precipitating bacteria to the culture medium is 1: (1-2).

[0042] S4, watering and curing the cyanide tailings further artificially improved in step S3, maintaining the moisture content of the improved matrix at 23-28%, with a watering frequency of 1-2 days / time and a curing period of 7 days; S5, using mixed sowing method to sow grass seeds on artificially improved cyanide tailings, combined with regular and irregular artificial maintenance, to enhance the germination rate and growth of plants, and restore the plant coverage 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 agents is (5-10):1; the microbial agents contain Bacillus subtilis, Trichoderma, actinomycetes, potassium humate, and vitamins, and the mixed grass seeds include seeds of ryegrass, tall fescue, bermudagrass, alfalfa, and sesbania.

[0043] 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 humate, and 2-5 parts by weight of vitamins, and the number of viable bacteria is ≥50 billion / gram.

[0044] Microbial agents such as Bacillus subtilis, Trichoderma, and actinomycetes have the functions of inhibiting pathogens, promoting plant growth, and enhancing plant resistance. They also improve soil structure, prevent soil compaction, and enhance soil fertility.

[0045] 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.

[0046] The soilless remediation method for cyanide tailings reservoir provided by the present invention is described below in conjunction with specific examples. Unless otherwise specified, the raw materials and reagents in the examples of the present application are purchased through commercial channels.

[0047] Example 1 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 taken, and the main chemical components thereof are shown in Table 1.

[0048] S1, level the cyanide tailings reservoir and till and loosen the 30cm thick tailings on the surface; S2, evenly laying the artificially improved materials 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; Among them, artificial improvement materials are composed of bio-based improvers, organic fertilizers and pellet promoter Artemisia sphaerocephala gum; The bio-based improver is the product of agricultural waste after being pulverized, expanded, and aerobic composted for 15 days; Organic fertilizer is 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, xylose, etc. The specific proportions of each component are shown in Table 2 (corresponding to 1# improved cyanide residue); S3, on modified cyanide slag at 5L / m 2 Spraying bacterial liquid to further improve the above cyanide tailings reservoir. The bacterial liquid is composed of functional bacterial agent microorganisms, carbonate precipitation bacteria and culture medium, and the main components of the culture medium are urea, calcium chloride and water; The mass ratio of microbial induced carbonate precipitation bacteria to culture medium is 1:1.

[0049] S4, watering and curing the cyanide tailings further artificially improved in step S3 for 7 days, maintaining the moisture content of the improved matrix at 25%, and the watering frequency is 1 day / time; S5, adopt mixed sowing method to sow grass seeds and carry out manual maintenance regularly.

[0050] The mixed sowing material is composed of mixed grass seeds and microbial agents. Specifically, the microbial agent contains the following components in parts 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 humate, and 5 parts by weight of vitamins, and the number of viable bacteria is ≥50 billion / gram.

[0051] 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.

[0052] Example 2-3 Compared with Example 1, the difference of Example 2-3 is that the ratio of each component in the artificially modified material in step S2 is changed, as shown in Table 2 (corresponding to 2# modified cyanide slag and 3# modified cyanide slag, respectively). The rest is roughly the same as Example 1 and will not be repeated here.

[0053] By adding materials in the proportions shown in Table 2, the physical and chemical properties and microecological environment of the cyanide tailings are 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. Mixed grass seeds are sown and artificial maintenance is performed regularly. The vegetation grows well. Figure 1 shown.

[0054] Table 1 Main chemical components of cyanide tailings before improvement Table 2 Improved material ratio Table 3 Physical and chemical parameters of improved cyanide tailings As can be seen from Table 3, the organic matter, ammonium nitrogen, available phosphorus, available potassium and other nutrient components of each group under different improvement schemes are all improved to a certain extent compared with the unimproved original slag. Among them, the organic matter content in the improved cyanide slag reaches the "extremely abundant" level, the ammonium nitrogen reaches the "middle to rich" level, the available phosphorus reaches the "middle to rich" level, and the available potassium reaches the "extremely abundant" level. At the same time, the pH value is reduced to a certain extent, from alkaline to neutral, which is more suitable for vegetation growth.

[0055] Figure 1 The vegetation growth diagram of Examples 1-3 and unimproved cyanide slag.

[0056] It can be seen that the unimproved 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 improved cyanide tailings were sown, and after 30 days, the plants in each group grew well.

[0057] Figure 2 This is a vegetation growth diagram of the vegetation grown for 60 days in Example 1. It can be seen that within 60 days, the vegetation grew well.

[0058] Example 4 This embodiment provides a soilless remediation method for a cyanide tailings reservoir. Compared with embodiment 1, embodiment 4 is different in that the improved cyanide tailings reservoir is different. Embodiment 4 improves the cyanide tailings of a cyanide tailings reservoir of a gold production enterprise in Guangxi, and its main chemical components are shown in Table 4. The rest is roughly the same as embodiment 1, and will not be repeated here.

[0059] Table 4 Main chemical components of cyanide tailings before improvement Figure 3 This is a vegetation growth diagram after 60 days of vegetation growth in Example 4. It can be seen that within 60 days, the vegetation grows well and the coverage can reach more than 90%.

[0060] Comparative Example 1 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, and the rest is substantially the same as Example 1 and will not be described again.

[0061] Observe the growth of vegetation. Figure 4 As shown, it can be seen that within 60 days, the vegetation germination rate was low, the plants were short and the growth was poor.

[0062] Comparative Example 2 Compared with Example 1, the main difference between Comparative Example 2 is that in step S2, the granulation promoter Artemisia sphaerocephala gum is not added to the artificially improved material, and the rest is generally the same as Example 1 and will not be repeated here.

[0063] Observe the growth of vegetation. Figure 5 As shown, it can be seen that within 60 days, the cyanide tailings without artemisia gum had poor water retention, low vegetation germination rate, and slow growth.

[0064] Comparative Example 3 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, and the rest is generally the same as Example 1 and will not be repeated here.

[0065] By observing the growth of vegetation, it can be seen that after adding the polyacrylamide water-retaining agent, the cyanide tailings has a certain water-retaining capacity and the vegetation grows well, but the vegetation height and leaf chlorophyll content are lower than those in Example 1, indicating that while improving the aggregate structure and water-retaining capacity of the cyanide tailings, the artemisia gum synergistically promotes the growth and reproduction of beneficial functional microorganisms, further promoting vegetation growth.

[0066] Comparative Example 4 Compared with Example 4, Comparative Example 4 is mainly different in that: no microbial-induced carbonate precipitation bacterial solution is sprayed, specifically: step S3 is not performed. The rest is generally the same as Example 4 and will not be repeated here.

[0067] Observe the growth of vegetation. 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 the vegetation.

[0068] Comparative Example 5 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 generally the same as Example 4 and will not be repeated here.

[0069] Observe the growth of vegetation. Figure 7 As 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 package can enhance plant stress resistance and promote plant growth.

[0070] Comparative Example 6 Compared with Example 4, the main difference is that in Example 4, an unimproved area of ​​the tailings pond is selected for mixed grass seed sowing, and the rest is generally the same as Example 4 and will not be repeated here.

[0071] Observe the growth of vegetation. Figure 8 As shown, it can be seen that within 60 days, the vegetation in the unimproved cyanide residue withered after germination, and no vegetation grew.

[0072] The preferred embodiments of the present invention are described above; however, the protection scope 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 according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention. These simple variations all belong to the protection scope of the present invention.

[0073] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0074] In addition, 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 silo, characterized in that: The steps include: S1, level the cyanide tailings reservoir and till and loosen the 30 cm thick tailings on the surface; 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, an organic fertilizer and a pelletizing promoter; The bio-based improver is the product of agricultural waste after being pulverized, expanded, and aerobic 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; S3, spraying bacterial solution on the artificial soil layer, the amount of bacterial solution spraying is 2~5L / m 2 , in order to further improve the above-mentioned cyanide tailings reservoir artificially; The bacterial solution is composed of a functional bacterial agent and a culture medium; the functional bacterial agent is a microbial-induced carbonate precipitation bacterium; the main components of the culture medium are urea, calcium chloride and water; S4, watering and curing the cyanide tailings further artificially improved in step S3, maintaining the moisture content of the improved matrix at 23-28%, with a watering frequency of 1-2 days / time and a curing period of 7 days; S5, using mixed sowing method to sow grass seeds on artificially improved cyanide tailings, combined with regular and irregular artificial maintenance, to enhance the germination rate and growth of plants, and restore the plant coverage 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 repair method for cyanide tailings silo according to claim 1, characterized in that: In step S2, the artificial improvement material is composed of a bio-based improver, an organic fertilizer and artemisia gum in a mass ratio of (5-10): (1-5): (0.2-0.4).

3. The soilless repair method for the cyanide tailings reservoir according to claim 1, characterized in that: The mass ratio of the microbial inducing carbonate precipitation bacteria to the culture medium is 1:(1-2).

4. The soilless repair method for the cyanide tailings silo according to claim 1 is characterized in that: In step S2, the mass ratio of the cyanidation tailings to the artificially modified material is 100:(5-10).

5. The soilless repair method for cyanide tailings silo according to claim 1, characterized in that: In step S1, the cyanide tailings are tailings produced by the gold cyanidation process, with a pH of 8.0-9.5, a particle mass with a particle size greater than 0.075 mm not exceeding 20% ​​of the total mass, main components being SiO2, Al2O3, and Fe2O3, a cyanide content less than 300 mg / kg, and a water content not greater than 20%.

6. The soilless repair method for cyanide tailings silo according to claim 1, characterized in that: 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%.

7. The soilless remediation method for cyanide tailings silo 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 humate, and 2-5 parts by weight of vitamins, and the number of viable bacteria is ≥50 billion / gram.

8. The soilless remediation method for cyanide tailings silo according to claim 1, characterized in that: 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.

9. The soilless repair method for cyanide tailings silo according to claim 1, characterized in that: The agricultural waste includes one or more of corn stalks, rice husks, and sugarcane bagasse.

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