Coal gangue ceramsite-based subsidence area reclamation land soil profile reconstruction method

Abstract

The invention discloses a subsidence area reclamation land soil profile reconstruction method based on coal gangue ceramsite, relates to the technical field of subsidence area reclamation land soil reconstruction, and solves the problems that in the prior art, reclamation soil is filled with coal gangue and fly ash, coal-based solid waste is directly adopted as a filling matrix, then a soil layer is covered for reclamation, and the soil is not easy to reconstruct. The productivity recovery of the reclamation land is slow, and harmful substances in the coal gangue and the fly ash are extremely easy to migrate, so that the soil pollution of the reclamation land is caused. A subsidence area reclamation land soil profile reconstruction method based on coal gangue ceramsite comprises the following steps that S1, coal gangue larger than 5 mm is crushed to form coal gangue powder, and then the coal gangue powder, an adhesive and a fly ash expansion curing agent are mixed and made into pellets; through layered construction, a reasonable soil profile structure is optimized, the soil quality of the reclamation land is improved, the productivity of the reclamation land can be rapidly recovered, and meanwhile safe absorption of coal-based solid waste such as coal gangue and coal ash is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil reconstruction in reclaimed land of subsidence areas, and specifically to a method for reconstructing the soil profile of reclaimed land in subsidence areas based on coal gangue ceramsite. Background Technique

[0002] China is a large energy-consuming country. The resource endowment characteristics of "rich in coal, poor in oil, and less in gas" determine that in the current and future for a long time, the dominant position and stabilizer role of coal in China's energy system will not change. However, about 96% of China's coal mining comes from underground mining, and 4% comes from surface mining. In the high water table areas in the eastern part of China, underground mining often leads to surface subsidence and waterlogging, and a large amount of cultivated land is damaged. In addition, during the process of coal resource mining and use, solid wastes such as coal gangue and fly ash are formed. The large-scale stacking of these solid wastes not only occupies land but also causes pollution. Therefore, both the reclamation of subsidence areas and the safe disposal of coal-based solid wastes are difficult problems that need to be solved urgently in mining areas.

[0003] However, for the existing method of reclaiming soil by filling with coal gangue and fly ash, directly using these coal-based solid wastes as filling matrices and then covering with a soil layer for reclamation, the productivity recovery of the reclaimed land is slow, and the harmful substances in coal gangue and fly ash are extremely likely to migrate, causing soil pollution in the reclaimed land. Therefore, it does not meet the existing requirements, and for this reason, we propose a method for reconstructing the soil profile of reclaimed land in subsidence areas based on coal gangue ceramsite. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for reconstructing the soil profile of reclaimed land in subsidence areas based on coal gangue ceramsite, so as to solve the problems proposed in the above background technique, such as reclaiming soil by filling with coal gangue and fly ash, directly using these coal-based solid wastes as filling matrices and then covering with a soil layer for reclamation, the slow productivity recovery of the reclaimed land, and the extremely easy migration of harmful substances in coal gangue and fly ash, causing soil pollution in the reclaimed land, etc.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A method for reconstructing the soil profile of reclaimed land in subsidence areas based on coal gangue ceramsite, including the following steps:

[0006] S1: Crush coal gangue larger than 5 mm to form coal gangue powder, then mix the coal gangue powder, binder, and fly ash expansion curing agent and make them into material balls, and put the material balls into a kiln for calcination to form coal gangue ceramsite;

[0007] S2: Strip the topsoil of the coal mining subsidence area, and transport the stripped topsoil to a nearby place for separate storage;

[0008] S3: Crush the gangue produced during coal mining, screen the crushed gangue, and fill the gangue that has not passed through the sieve into the bottom layer to form a gangue filling parent material layer;

[0009] S4: Cover the gangue filling parent material layer with mature soil where vegetation grows all year round on the surface to form a mature soil layer;

[0010] S5: Mix fly ash and the gangue that has passed through the sieve in S3 in a certain proportion, and successively fill it on the mature soil layer, and then level and compact it to form a fine-grained coal-based solid waste water isolation layer;

[0011] S6: Mix fly ash with water and fill it on the fine-grained coal-based solid waste water isolation layer to form a fly ash improvement layer;

[0012] S7: Mix coal gangue ceramsite, topsoil, and gangue to form a mixture, add water to the mixed mixture, and then fill the water-added mixture on the fly ash improvement layer to form a gangue ceramsite water retention layer;

[0013] S8: Evenly cover the topsoil above the fly ash improvement layer to form a planting layer.

[0014] Preferably, the coal gangue ceramsite includes a honeycomb-shaped expanded core body, and the outside of the honeycomb-shaped expanded core body is wrapped with a layer of rubber ball shell, and the outer surface of the rubber ball shell is hard and rough.

[0015] Preferably, the outer surface of the rubber ball shell is provided with a plurality of randomly distributed external pores, and the inside of the honeycomb-shaped expanded core body is provided with a plurality of pores.

[0016] Preferably, the mixing ratio of fly ash to water in S6 is 1:0.4.

[0017] Preferably, the crushed gangue in S3 is screened with a 5 mm sieve, and the gangue larger than 5 mm is used to form the gangue filling parent material layer, and the gangue smaller than 5 mm is used to prepare the fine-grained coal-based solid waste water isolation layer.

[0018] Preferably, the mixing ratio of ceramsite, topsoil, and gangue in S7 is 2:7:1 by volume.

[0019] Preferably, the water added to the mixture of ceramsite, topsoil, and gangue after mixing is 12% of the total weight of the mixture.

[0020] Preferably, the coal gangue powder formed after crushing the coal gangue in S1 passes through a 400-mesh sieve.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The present invention makes ceramsite by using coal-based solid wastes such as coal gangue and fly ash, and uses the porous and pollution-free characteristics of the ceramsite for soil improvement of reclaimed land. As an interlayer for reconstructing the soil profile of reclaimed land, through layered construction, a reasonable soil profile structure is optimized, the soil quality of reclaimed land is improved, the productivity of reclaimed land can be quickly restored, and at the same time, the safe disposal of coal-based solid wastes such as coal gangue and fly ash is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the soil stratification of the present invention;

[0024] Figure 2 It is a schematic structural diagram of the coal gangue ceramsite of the present invention;

[0025] Figure 3 It is a schematic flow diagram of the soil reconstruction of the reclaimed land in the subsidence area of the present invention.

[0026] In the figure: 1. Coal gangue filling parent material layer; 2. Mellow soil layer; 3. Fine-particle-size coal-based solid waste water isolation layer; 4. Fly ash improvement layer; 5. Gangue ceramsite water retention layer; 6. Planting layer; 7. Coal gangue ceramsite; 71. Rubber ball shell; 72. Honeycomb-shaped expansion core body; 73. External air holes; 74. Pores. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0028] As Figures 1 to 3 shown, a method for reconstructing the soil profile of the reclaimed land in the subsidence area based on coal gangue ceramsite includes the following steps:

[0029] S1: Crush the coal gangue larger than 5 mm to form coal gangue powder, then mix the coal gangue powder, binder, and fly ash expansion curing agent and make them into material balls, and put the material balls into the kiln body for calcination to form coal gangue ceramsite 7;

[0030] S2: Strip the topsoil of the coal mining subsidence area, and transport the stripped topsoil to a nearby place for separate storage;

[0031] S3: Crush the coal gangue produced during the coal mining process, screen the crushed coal gangue, and fill the coal gangue that has not passed through the sieve to the bottom layer to form the coal gangue filling parent material layer 1;

[0032] S4: Cover the mellow soil with perennial vegetation growth on the surface on the coal gangue filling parent material layer to form the mellow soil layer 2;

[0033] S5: Mix the fly ash and the gangue passing through the sieve in S3 in a certain proportion, and sequentially fill them on the cultivated soil layer, and then level and compact them to form a fine-grained coal-based solid waste water barrier layer 3;

[0034] S6: Mix the fly ash with water and fill it on the fine-grained coal-based solid waste water barrier layer to form a fly ash improved layer 4;

[0035] S7: Mix the coal gangue ceramsite 7, topsoil, and gangue to form a mixture, add water to the mixed mixture, and then fill the water-added mixture on the fly ash improved layer to form a gangue ceramsite water retention layer 5;

[0036] S8: Uniformly cover the topsoil above the fly ash improved layer to form a planting layer 6.

[0037] The gangue powder formed after crushing the gangue in S1 passes through a 400-mesh sieve.

[0038] The crushed gangue in S3 is screened using a 5-mm sieve. The gangue larger than 5 mm is used to form the gangue filling parent material layer 1, and the gangue smaller than 5 mm is used to prepare the fine-grained coal-based solid waste water barrier layer 3.

[0039] In S6, the mixing ratio of fly ash to water is 1:0.4. This ratio can ensure that the mixture formed by fly ash and water reaches the optimal flow plastic state, and the slump is controlled within 50 - 70 mm, which is convenient for pumping construction and can form an anti-seepage layer with a density of more than 90%.

[0040] The coal gangue ceramsite 7 includes a honeycomb-shaped expansion core body 72. The outside of the honeycomb-shaped expansion core body 72 is wrapped with a layer of rubber ball shell 71. The outer surface of the rubber ball shell 71 is hard and rough, and there are multiple randomly distributed external pores 73 on the outer surface of the rubber ball shell 71. There are multiple pores 74 inside the honeycomb-shaped expansion core body 72.

[0041] In S7, the mixing ratio of ceramsite, topsoil, and gangue is 2:7:1 by volume, and the water added to the mixture of ceramsite, topsoil, and gangue after mixing is 12% of the total weight of the mixture.

[0042] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A soil profile reconstruction method for reclamation of subsidence area based on coal gangue ceramsite, characterized in that: The steps include: S1: crushing the coal gangue larger than 5 mm to form coal gangue powder, then mixing the coal gangue powder, a binder, and a fly ash expansion curing agent to form a ball, and placing the ball in a kiln body for calcining to form coal gangue ceramsite (7); S2: The topsoil in the coal mining subsidence area is stripped and transported to a nearby location for separate storage; S3: crushing the gangue produced in the coal mining process, screening the crushed gangue, and filling the gangue that has not passed through the screen into the bottom layer to form a gangue filling parent material layer (1); S4: Covering the coal gangue filling parent material layer with mature soil with vegetation growing on the surface all year round to form a mature soil layer (2); S5: fly ash and the coal gangue that has passed through the screen in S3 are mixed in a certain proportion, filled onto the cooked soil layer in sequence, and leveled and compacted to form a fine-grained coal-based solid waste water-proof layer (3); S6: mixing fly ash with water and filling the mixture onto the fine-grained coal-based solid waste water-proof layer to form a fly ash modified layer (4); S7: Mixing the gangue ceramsite (7), topsoil and gangue to form a mixture, adding water to the mixed mixture, and then filling the mixture with water onto the fly ash improved layer to form a gangue ceramsite water-retaining layer (5); S8: Evenly cover the fly ash improved layer with topsoil to form a planting layer (6).

2. The method for reconstructing soil profile of reclamation land in subsidence area based on coal gangue ceramsite according to claim 1 is characterized in that: The gangue ceramsite (7) comprises a honeycomb expanded core (72), the outer side of the honeycomb expanded core (72) is wrapped with a layer of ball shell (71), and the surface of the ball shell (71) is hard and rough.

3. The method for reconstructing soil profile of reclamation land in subsidence area based on coal gangue ceramsite according to claim 2 is characterized in that: The outer surface of the ball shell (71) is provided with a plurality of randomly distributed external pores (73), and the interior of the honeycomb expansion core (72) is provided with a plurality of pores (74).

4. The method for reconstructing soil profile of reclamation land in subsidence area based on coal gangue ceramsite according to claim 1 is characterized in that: The mixing ratio of fly ash to water in S6 is 1:0.

4.

5. The method for reconstructing soil profile of reclamation land in subsidence area based on coal gangue ceramsite according to claim 1, characterized in that: The crushed gangue in S3 is screened using a 5 mm sieve, and the gangue larger than 5 mm is used to form a gangue filling parent material layer (1), and the gangue smaller than 5 mm is used to prepare a fine-grained coal-based solid waste waterproof layer (3).

6. The method for reconstructing soil profile of reclamation land in subsidence area based on coal gangue ceramsite according to claim 1, characterized in that: The mixing ratio of ceramsite, topsoil and coal gangue in S7 is 2:7:1 by volume.

7. The method for reconstructing soil profile of reclaimed land in a subsidence area based on coal gangue ceramsite according to claim 6, characterized in that: The water added to the mixture of ceramsite, topsoil and coal gangue accounts for 12% of the total weight of the mixture.

8. The method for reconstructing soil profile of reclamation land in subsidence area based on coal gangue ceramsite according to claim 1, characterized in that: The gangue powder formed after the gangue in S1 is crushed is passed through a 400-mesh sieve.

Images