Acid mine in-situ remediation material and acid mine in-situ remediation method

Abstract

The invention provides an acid mine in-situ remediation material and an acid mine in-situ remediation method, and belongs to the technical field of mine remediation. The repairing material is prepared from, by mass, 50-60 parts of fly ash aerated concrete particles and 30-40 parts of sludge compost, the fly ash aerated concrete particles are obtained after building waste residues made of fly ash aerated concrete materials are crushed, the sludge compost is obtained by fermenting municipal sludge, the repairing material can synchronously repair the acid mine through multiple synergistic mechanisms, and the repairing efficiency is improved. The method has the advantage of being good in repairing effect, meanwhile, a large amount of building waste residues and municipal sludge can be recycled, and the repairing cost of the acid mine is synchronously reduced.

Description

Technical Field

[0001] The present application relates to the field of mine restoration technology, and in particular to an acid mine in-situ restoration material and an acid mine in-situ restoration method. Background Art

[0002] While the development of mining resources brings good economic benefits, it also causes huge damage to the environment, especially the mining of acidic mines (such as pyrite, lead and zinc mines, etc.). The corresponding acidic minerals will produce a large amount of acidic wastewater containing heavy metals after being washed by rainwater. The production of acidic wastewater will further lead to soil acidification, groundwater pollution and heavy metal enrichment in the ecological chain, seriously threatening biodiversity.

[0003] Currently, the mainstream technologies for acid mine remediation include chemical neutralization (such as adding lime), covering and isolation, or vegetation restoration. Among them, the chemical neutralization method requires repeated addition of alkaline substances, which only focuses on pH adjustment, and excessive use can easily lead to soil compaction, which is not conducive to vegetation growth; the covering and isolation method has the problems of high cost, poor terrain adaptability, and easy failure after the diaphragm is broken; the plant restoration method has the problems of low efficiency and long time consumption.

[0004] Therefore, there is an urgent need to develop a technology that can utilize multiple synergistic mechanisms to simultaneously achieve acid mine remediation, so as to make up for the shortcomings of the current single remediation method. Summary of the Invention

[0005] The purpose of this application is to provide an in-situ remediation material and an in-situ remediation method for acid mines. The remediation material can use multiple synergistic mechanisms to simultaneously remediate acid mines, and has the advantage of better remediation effect. At the same time, it can also realize the reuse of large amounts of construction waste and municipal sludge and simultaneously reduce the remediation cost of acid mines.

[0006] The embodiment of the present application is implemented as follows:

[0007] In a first aspect, an embodiment of the present application provides an in-situ remediation material for an acidic mine. Calculated by weight, the remediation material comprises 50 to 60 parts of fly ash aerated concrete particles and 30 to 40 parts of sludge compost. The fly ash aerated concrete particles are obtained by crushing construction waste residue made of fly ash aerated concrete, and the sludge compost is obtained by fermenting municipal sludge.

[0008] In the above technical solution, a mixture of fly ash aerated concrete particles (obtained from crushed construction waste slag) and sludge compost (obtained from fermentation of municipal sludge) of the above mass fractions is used as a repair material for acid mines. On the one hand, fly ash aerated concrete particles are rich in OH that can slowly release -The calcium oxide has a certain neutralizing effect on acidic substances, and it has a porous structure that can absorb heavy metals; at the same time, the fly ash aerated concrete particles have a relatively suitable hardness, which can effectively support the sludge compost, so that the repair material has a relatively excellent structural stability (especially under the impact of water flow) to achieve a long-term repair effect; and, it can also make the repair material have a relatively suitable looseness (suitable looseness can make the sludge compost in the repair material play a better water retention role); in addition, the sludge compost also contains a large amount of organic matter, which can provide rich nutrients for plant production, thereby facilitating vegetation growth. At the same time, the sludge compost can also effectively prevent rainwater from entering the mineral material and producing acidic wastewater containing heavy metals. The repair material provided in the embodiment of the present application can not only neutralize acidic substances and adsorb heavy metals, but also prevent rainwater from entering the mineral material to reduce the generation of acidic wastewater. In addition, it also helps vegetation growth and has a relatively suitable structural stability (i.e., it has a long-term repair effect). It can use multiple synergistic mechanisms to simultaneously repair acid mines, with the advantage of better repair effect. On the other hand, by introducing construction waste residue made of fly ash aerated concrete and sludge compost obtained by fermenting municipal sludge into the field of mine remediation materials, it is also possible to reuse a large amount of construction waste residue and municipal sludge and simultaneously reduce the remediation cost of acidic mines.

[0009] In some optional embodiments, the preparation method of fly ash aerated concrete includes the following steps: adding 60-70 parts of fly ash, 20-30 parts of gel material and 1-10 parts of gas generating agent to water and mixing them in parts by mass to obtain a slurry; injecting the slurry into a mold for static gasification treatment to obtain a blank with a porous structure; transferring the blank to an autoclave for autoclave curing treatment to obtain fly ash aerated concrete.

[0010] By preparing according to the above process, fly ash aerated concrete with suitable hardness and porosity can be prepared. After being used in the construction field, it can be crushed and used as an in-situ repair material for acid mines, and can play a good role in acid mine repair.

[0011] In some optional embodiments, the particle size of the fly ash aerated concrete particles is 10 to 20 mm.

[0012] In the above technical solution, the use of fly ash aerated concrete particles in the above particle size range can, on the one hand, effectively support sludge composting and improve the structural stability of the repair material; on the other hand, it can also make the repair material have a more suitable looseness, which is suitable for the growth of upper-layer plants.

[0013] In some optional embodiments, the method for preparing sludge compost includes the following steps: mixing municipal sludge with straw so that the carbon-nitrogen ratio in the mixed system is (20-30):1 to obtain a fermentation mixture; aerobic fermentation treatment of the fermentation mixture, wherein the fermentation treatment temperature is 55-65°C and the fermentation treatment time is 3-8 days to obtain sludge compost.

[0014] In the above technical solution, sludge compost is prepared by aerobic fermentation treatment. Compared with anaerobic fermentation treatment, aerobic fermentation takes a shorter time and sludge compost can be obtained faster. At the same time, aerobic fermentation can make the material decompose more thoroughly, thereby facilitating plant absorption and utilization. In addition, since the pH of the decomposition products of aerobic fermentation are generally close to neutral, it is not easy to damage plant roots.

[0015] In a second aspect, an embodiment of the present application provides an in-situ remediation method for an acid mine, comprising the following steps: S1 leveling the surface of the acid mine; S2 laying an acid isolation layer on the leveled surface, the acid isolation layer comprising the remediation material provided in the embodiment of the first aspect.

[0016] In the above technical solution, an acidified isolation layer containing repair materials is laid on the surface of the leveled acid mine. The repair materials can not only neutralize acidic substances but also adsorb heavy metals. At the same time, they can prevent rainwater from entering the mineral materials, thereby reducing the generation of acidic wastewater. In addition, they also contribute to the growth of vegetation and have a more suitable structural stability, thereby enabling the acidified isolation layer to use multiple synergistic mechanisms to simultaneously repair the acid mine, which has the advantage of better repair effect.

[0017] In some optional embodiments, the thickness of the acidified isolation layer is 10 to 15 cm.

[0018] In the above technical solution, the thickness of the acid isolation layer is limited to the above range, so that the acid isolation layer has an appropriate thickness, thereby having a better acid mine repair effect.

[0019] In some optional embodiments, the restoration method further comprises: laying a growth substrate layer on the side of the acidified isolation layer facing away from the ground, and planting plants on the growth substrate layer.

[0020] In the above technical solution, a growth matrix layer is further laid on the acidified isolation layer and plants are planted on the growth matrix layer (plants can absorb, degrade, transform or fix pollutants in soil and water), which can further improve the remediation effect of acid mines.

[0021] In some optional embodiments, the thickness of the growth substrate layer is 10 to 20 cm.

[0022] In the above technical solution, the thickness of the growth matrix layer is limited to the above range, so that the upper growth matrix layer has an appropriate thickness, which is conducive to better growth of plants.

[0023] In some optional embodiments, the growth matrix layer includes 60-80 parts of guest soil, 10-20 parts of humus soil and 5-10 parts of zeolite, calculated by weight.

[0024] In the above technical solution, the growth matrix layer is composed of multiple components in the above mass fractions, which can provide relatively sufficient nutrition for plant growth and also facilitate the extension of plant roots.

[0025] In some alternative embodiments, the plant comprises at least one of tall fescue, amorpha, alfalfa, and sea buckthorn.

[0026] In the above technical solution, the plants are composed of the above-mentioned multiple varieties, which can integrate the advantages of multiple plants together, thereby improving the repair effect of acid mines. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0028] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to three situations: “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0029] In addition, in the description of this application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a to value b" includes the two end values ​​"a" and "b", and the "unit of measurement" in "value a to value b+unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0030] The following is a detailed description of an acid mine in-situ remediation material and an acid mine in-situ remediation method according to an embodiment of the present application.

[0031] In a first aspect, an embodiment of the present application provides an in-situ remediation material for an acidic mine. Calculated by weight, the remediation material comprises 50 to 60 parts of fly ash aerated concrete particles and 30 to 40 parts of sludge compost. The fly ash aerated concrete particles are obtained by crushing construction waste residue made of fly ash aerated concrete, and the sludge compost is obtained by fermenting municipal sludge.

[0032] In this application, a mixture of the above-mentioned mass fractions of fly ash aerated concrete particles (obtained from crushed construction waste slag) and sludge compost (obtained from fermentation of municipal sludge) is used as a repair material for acid mines. On the one hand, fly ash aerated concrete particles are rich in OH-releasing - The calcium oxide has a certain neutralizing effect on acidic substances, and it has a porous structure that can absorb heavy metals; at the same time, the fly ash aerated concrete particles have a relatively suitable hardness, which can effectively support the sludge compost, so that the repair material has a relatively excellent structural stability (especially under the impact of water flow) to achieve a long-term repair effect; and, it can also make the repair material have a relatively suitable looseness (suitable looseness can make the sludge compost in the repair material play a better water retention role); in addition, the sludge compost also contains a large amount of organic matter, which can provide rich nutrients for plant production, thereby facilitating vegetation growth. At the same time, the sludge compost can also effectively prevent rainwater from entering the mineral material and producing acidic wastewater containing heavy metals. The repair material provided in the embodiment of the present application can not only neutralize acidic substances and adsorb heavy metals, but also prevent rainwater from entering the ground to reduce the generation of acidic wastewater. In addition, it also helps vegetation growth and has a relatively suitable structural stability (i.e., it has a long-term repair effect). It can use multiple synergistic mechanisms to simultaneously repair acid mines, with the advantage of better repair effect. On the other hand, by introducing construction waste residue made from fly ash aerated concrete and sludge compost obtained from fermentation of municipal sludge into the field of mine remediation materials, it is possible to reuse large amounts of construction waste residue and municipal sludge and simultaneously reduce the cost of remediation of acid mines. It should be noted that in the field of mine remediation technology, fly ash (industrial solid waste discharged from coal-fired power plants, fine ash collected from flue gas, mainly composed of silica, alumina, and calcium oxide, etc.) is currently widely used. However, fly ash has a small particle size (mostly micrometers) and low hardness, making it difficult to effectively support sludge compost. The structure of the remediation material is prone to collapse under the impact of water flow. In addition, the overall remediation material is also relatively dense, making it difficult for the sludge compost to effectively retain water.

[0033] In this application, researchers innovatively introduced fly ash aerated concrete particles into the field of mine remediation technology. Fly ash aerated concrete is currently mainly used in the construction field. Fly ash aerated concrete uses fly ash as the main raw material, mixed with cement, lime, gypsum, etc., and is a porous lightweight material made through processes such as gasification treatment and autoclaving curing. It is often used as a building insulation material. There are currently no reports on its application in the field of mine remediation. With the advantages of its granular shape and high hardness, it can effectively make up for the defects of fly ash. At the same time, introducing construction waste slag made of fly ash aerated concrete into the field of mine remediation materials can also achieve the reuse of a large amount of construction solid waste.

[0034] It should be noted that sludge compost is obtained by fermenting municipal sludge (the annual output of municipal sludge in China exceeds 60 million tons, with an organic matter content of 40-60%, and can be used as a soil improvement matrix). The main roles of sludge compost in remediation materials are: first, sludge compost is rich in organic matter, which can provide nutrients for the growth of upper-layer plants; second, sludge compost has a water-retention function (derived from its water absorption), which can not only provide water for the growth of upper-layer materials, but also block the flow of water to the lower ground, reducing the generation of acidic wastewater. At the same time, introducing sludge compost obtained by fermenting municipal sludge into the field of mine remediation materials can also realize the reuse of large amounts of municipal sludge.

[0035] In order to better understand the technical solution, a preparation method of fly ash aerated concrete is used for auxiliary explanation.

[0036] As an example, the preparation method of fly ash aerated concrete includes the following steps: adding 60-70 parts of fly ash, 20-30 parts of gel material and 1-10 parts of gas generating agent to water and mixing them in parts by mass to obtain a slurry; injecting the slurry into a mold for static gasification treatment to obtain a blank with a porous structure; transferring the blank to an autoclave for autoclave curing treatment to obtain fly ash aerated concrete.

[0037] In this embodiment, the fly ash aerated concrete having suitable hardness and porosity can be prepared according to the above process. After being used in the construction field, the fly ash aerated concrete can be crushed and used as an in-situ repair material for acid mines, and can play a good role in acid mine repair.

[0038] As an example, the gel material is selected from at least one of cement and lime, and the gas generating agent is selected from at least one of aluminum powder and zinc powder.

[0039] As an example, in the step of static gasification treatment, the static time is 20 to 40 minutes, for example but not limited to any one of 20 minutes, 25 minutes, 30 minutes, 35 minutes and 40 minutes, or a range between any two of them.

[0040] As an example, in the step of autoclave curing treatment, the treatment temperature is 170-190°C, for example but not limited to the treatment temperature being any one of 170°C, 175°C, 180°C, 185°C and 190°C, or a range between any two of them; the treatment pressure is 0.9-1.2MPa, for example but not limited to the treatment pressure being any one of 0.9MPa, 1.0MPa, 1.1MPa and 1.2MPa, or a range between any two of them; the treatment time is 7-9h, for example but not limited to the time being any one of 7h, 7.5h, 8h, 8.5h and 9h, or a range between any two of them.

[0041] It should be noted that the mass proportion of water in the slurry is not limited and can be adaptively adjusted according to actual needs. For example, the mass proportion of water in the slurry is 55-60%, such as but not limited to any one of 55%, 56%, 57%, 58%, 59% and 60% or a range of values ​​between any two of them.

[0042] It should be noted that the particle size of fly ash aerated concrete particles is not limited and can be adaptively adjusted according to actual needs.

[0043] As an example, the particle size of fly ash aerated concrete particles is 10 to 20 mm, for example, but not limited to, the particle size is any one of 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm and 20 mm, or a range between any two of them.

[0044] In this embodiment, the use of fly ash aerated concrete particles in the above-mentioned particle size range can, on the one hand, effectively support sludge composting and improve the structural stability of the repair material; on the other hand, it can also make the repair material have a more appropriate looseness, which is suitable for the growth of upper-layer plants.

[0045] It should be noted that the fermentation method is not limited, for example, it can be aerobic fermentation or anaerobic fermentation, and can be set according to actual needs.

[0046] As an example, the preparation method of sludge compost includes the following steps: mixing municipal sludge with straw (sludge has a high nitrogen content and a low carbon content, and the C / N ratio is usually low. Straw, as a high-carbon material, can significantly increase the overall C / N ratio to a suitable range for microbial metabolism, promote the decomposition of organic matter and the synthesis of humus) so that the carbon-nitrogen ratio in the mixed system is (20 to 30):1, for example, but not limited to, the carbon-nitrogen ratio is any one of 20:1, 22:1, 24:1, 26:1, 28:1 and 30:1, or a range between any two of them. , obtaining a fermentation mixture; subjecting the fermentation mixture to aerobic fermentation treatment, wherein the fermentation treatment temperature is 55-65°C (for example, but not limited to, the temperature is any one of 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C and 65°C, or a range between any two of them), and the fermentation treatment time is 3-8 days (for example, but not limited to, the time is any one of 3 days, 4 days, 5 days, 6 days, 7 days and 8 days, or a range between any two of them), to obtain sludge compost.

[0047] In this embodiment, sludge compost is prepared by aerobic fermentation treatment. Compared with anaerobic fermentation treatment, aerobic fermentation takes a shorter time and sludge compost can be obtained more quickly. At the same time, aerobic fermentation can make the material decompose more thoroughly, thereby facilitating plant absorption and utilization. In addition, since the pH of the decomposition products of aerobic fermentation is generally close to neutral, it is not easy to damage plant roots.

[0048] As an example, the repair material also includes 1 to 5 parts of heavy metal adsorbent (such as biochar). The addition of the heavy metal adsorbent can synergistically act with the fly ash aerated concrete particles to improve the adsorption effect of heavy metals.

[0049] As an example, the repair material further includes 1 to 5 parts of a pH regulator (such as sulfur powder). The addition of the pH regulator can make the overall pH of the repair material close to neutral.

[0050] It should be noted that the functional components not specifically described or limited in the repair material can be set according to conventional selection in the art.

[0051] In a second aspect, an embodiment of the present application provides an in-situ remediation method for an acid mine, comprising the following steps: S1 leveling the surface of the acid mine; S2 laying an acid isolation layer on the leveled surface, the acid isolation layer comprising the remediation material provided in the embodiment of the first aspect.

[0052] In this application, an acidified isolation layer containing repair materials is laid on the surface of the leveled acid mine. The repair materials can not only neutralize acidic substances and adsorb heavy metals, but also prevent rainwater from entering the mineral materials, thereby reducing the generation of acidic wastewater. In addition, it also helps vegetation growth and has a more suitable structural stability, so that the acidified isolation layer can use multiple synergistic mechanisms to simultaneously repair the acid mine, which has the advantage of better repair effect.

[0053] It should be noted that there is no limit to the laying method of the acidified isolation layer. For example, all the materials of the acidified isolation layer can be laid on the surface layer and compacted to obtain the first part of the acidified isolation layer, that is, a one-step laying construction method is adopted; or a part of the materials of the acidified isolation layer can be laid on the surface layer and compacted to obtain the first part of the acidified isolation layer, and then the remaining part of the materials of the acidified isolation layer can be laid on the first part of the acidified isolation layer and compacted to obtain the second part of the acidified isolation layer, that is, a step-by-step laying construction method is adopted.

[0054] As an example, the compaction degree of the acidified isolation layer is ≥85%.

[0055] It should be noted that the thickness of the acidified isolation layer is not limited and can be adaptively adjusted according to actual needs.

[0056] As an example, the thickness of the acidified isolation layer is 10-15 cm, for example but not limited to any one of 10 cm, 11 cm, 12 cm, 13 cm, 14 cm and 15 cm, or a range between any two of the thicknesses.

[0057] In this embodiment, the thickness of the acid isolation layer is limited to the above range, so that the acid isolation layer has an appropriate thickness, thereby achieving a better acid mine remediation effect.

[0058] As an example, the restoration method further includes: laying a growth substrate layer on a side of the acidified isolation layer facing away from the surface layer, and planting plants on the growth substrate layer.

[0059] In this embodiment, a growth matrix layer is further laid on the acidified isolation layer and plants are planted on the growth matrix layer (plants can absorb, degrade, transform or fix pollutants in soil and water), which can further improve the remediation effect of acid mines.

[0060] It should be noted that the laying method of the growth matrix layer can refer to the laying method of the acidified isolation layer.

[0061] As an example, the compaction degree of the growth matrix layer is ≥80%.

[0062] It should be noted that the thickness of the growth matrix layer is not limited and can be adaptively adjusted according to actual needs.

[0063] As an example, the thickness of the growth substrate layer is 10-20 cm, for example but not limited to any one of 10 cm, 12 cm, 14 cm, 16 cm, 18 cm and 20 cm, or a range between any two of the thicknesses.

[0064] In this embodiment, the thickness of the growth substrate layer is limited to the above range, so that the upper growth substrate layer has an appropriate thickness, which is conducive to better growth of plants.

[0065] As an example, the growth matrix layer includes 60-80 parts of guest soil, 10-20 parts of humus soil and 5-10 parts of zeolite, calculated by weight.

[0066] In this embodiment, the growth matrix layer is composed of the above-mentioned multiple components in the above-mentioned mass fractions, which can provide relatively sufficient nutrition for plant growth and also facilitate the extension of plant roots.

[0067] As an example, the plant includes at least one of tall fescue, amorpha, alfalfa, and sea buckthorn.

[0068] In this embodiment, the plants are composed of the above-mentioned multiple varieties, which can integrate the advantages of multiple plants and thus improve the restoration effect of acid mines.

[0069] As an example, the plants include tall fescue: amorpha: alfalfa in a ratio of 5:3:2.

[0070] It should be noted that any steps not specifically described or limited in the in-situ remediation process of acid mines may be arranged according to conventional options in the art.

[0071] The features and performance of the present application are further described in detail below in conjunction with the examples, wherein the repair object is an acidic pyrite mine.

[0072] Example 1

[0073] The present invention provides an in-situ remediation method for acid mines, comprising the following steps:

[0074] S1 is used to level the surface of acidic pyrite mines.

[0075] S2 was laid using a two-step method, forming a 10cm-thick, 85% compacted acidified barrier layer on the leveled surface. The raw materials for the acidified barrier layer, calculated by weight, include 55 parts fly ash aerated concrete particles (15mm in diameter), 35 parts aerobic fermented sludge compost, 2 parts biochar (heavy metal adsorbent), and 2 parts sulfur powder (pH adjuster).

[0076] Construction waste residue made of fly ash aerated concrete is collected and then crushed to obtain fly ash aerated concrete particles. The preparation method of fly ash aerated concrete includes the following steps: adding 65 parts of fly ash, 12 parts of cement, 12 parts of lime and 5 parts of zinc powder to 120 parts of water by weight and mixing to obtain a slurry; injecting the slurry into a mold and allowing it to stand for aeration treatment for 30 minutes to obtain an embryo with a porous structure; transferring the embryo to an autoclave for autoclave curing treatment (treatment temperature of 180°C, treatment pressure of 1 MPa, treatment time of 8 hours) to obtain fly ash aerated concrete.

[0077] The preparation method of sludge compost includes the following steps: mixing municipal sludge with straw so that the carbon-nitrogen ratio in the mixed system is 25:1 to obtain a fermentation mixture; aerobic fermentation treatment of the fermentation mixture, wherein the fermentation treatment temperature is 60°C and the fermentation treatment time is 5 days to obtain sludge compost.

[0078] S3 was laid using a two-step construction method, forming a 15cm-thick, 80% compacted growth substrate layer on top of the acidified isolation layer. Plants were then planted on top of the growth substrate. The growth substrate consisted of 70 parts imported soil, 15 parts humus, and 5 parts zeolite, calculated by weight. The plants consisted of tall fescue, amorpha fruticosa, and alfalfa in a ratio of 5:3:2. Six months later, the soil pH in the area was measured to be 7.0, the vegetation coverage was 80%, and the surface moisture content was 30%.

[0079] Comparative Example 1

[0080] This comparative example provides an in-situ remediation method for acid mines. The only difference from Example 1 is that in step S2, all fly ash aerated concrete particles are replaced with fly ash. Six months later, the soil pH in the area was measured to be 6.0, the vegetation coverage was 40%, and the surface moisture content was 40%.

[0081] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. An acid mine in-situ repair material, characterized in that: Calculated by weight, the repair material includes 50-60 parts of fly ash aerated concrete particles and 30-40 parts of sludge compost, wherein the fly ash aerated concrete particles are obtained by crushing construction waste residue made of fly ash aerated concrete, and the sludge compost is obtained by fermenting municipal sludge.

2. The repair material according to claim 1, characterized in that The preparation method of fly ash aerated concrete comprises the following steps: According to parts by mass, 60-70 parts of fly ash, 20-30 parts of gel material and 1-10 parts of gas generating agent are added to water and mixed to obtain a slurry; injecting the slurry into a mold and subjecting it to a static gasification treatment to obtain an embryonic body with a porous structure; The embryo body is transferred to an autoclave for autoclaving and curing to obtain fly ash aerated concrete.

3. The repair material according to claim 1, characterized in that The particle size of the fly ash aerated concrete particles is 10 to 20 mm.

4. The repair material according to any one of claims 1 to 3, characterized in that The preparation method of the sludge compost comprises the following steps: mixing municipal sludge with straw so that the carbon-nitrogen ratio in the mixed system is (20-30):1 to obtain a fermentation mixture; and aerobic fermentation treatment of the fermentation mixture, wherein the fermentation treatment temperature is 55-65° C. and the fermentation treatment time is 3-8 days to obtain the sludge compost.

5. An in-situ remediation method for acid mines, characterized in that: The following steps are involved: S1: Leveling the surface of acid mines; S2: laying an acid isolation layer on the leveled surface layer, wherein the acid isolation layer comprises the repair material according to any one of claims 1 to 4.

6. The repair method according to claim 5, characterized in that: The thickness of the acidified isolation layer is 10 to 15 cm.

7. The repair method according to claim 5, characterized in that: The repair method further comprises: laying a growth substrate layer on a side of the acidified isolation layer away from the surface layer, and planting plants on the growth substrate layer.

8. The repair method according to claim 7, characterized in that: The thickness of the growth matrix layer is 10 to 20 cm.

9. The repair method according to claim 8, characterized in that: Calculated by weight, the growth matrix layer includes 60 to 80 parts of guest soil, 10 to 20 parts of humus soil and 5 to 10 parts of zeolite.

10. The repair method according to claim 7, characterized in that: The plant comprises at least one of tall fescue, amorpha fruticosa, alfalfa and sea buckthorn.