A method for classifying and separating coal gangue by quality and an ecological restoration method for all coal gangue based on the classification and separation treatment of coal gangue

Abstract

The present invention provides a method for classifying and separating coal gangue by quality and an ecological restoration method for all coal gangue based on the classified and quality-separated treatment of coal gangue, which relates to the technical fields of resource utilization of solid waste and ecological restoration. The method for classifying and separating coal gangue by quality provided by the present invention comprises the following steps: performing crushing and screening treatment on coal gangue to obtain coal, crushed stones with different particle sizes, machine-made sand and soil. The ecological restoration method for all coal gangue based on the classified and quality-separated treatment uses local coal gangue. Based on its homology with rock strata and soil layers, the coal gangue is first subjected to classified and quality-separated treatment, and the separated crushed stones, machine-made sand and soil are used for ecological restoration, which can eliminate the complex domestication and improvement links required for taking sand and soil from other places for ecological restoration, thereby reducing the cost of ecological restoration and improving the effect of ecological restoration. At the same time, the separated coal can be used as fuel, and part of the coal with high ash content is used as an auxiliary material for the topsoil layer.

Description

Technical Field

[0001] The present invention relates to the technical fields of resource utilization of solid waste and ecological restoration, and particularly relates to a method for grading and separating coal gangue by quality and an all-coal gangue ecological restoration method based on the grading and separating treatment of coal gangue. Background Art

[0002] China ranks third in the world in terms of cultivated land area. However, the per capita cultivated land area is relatively small, less than 1 / 3 of the world's per capita cultivated land area. Moreover, the terrain in China is extremely complex, with various terrains and landforms such as mountains, plateaus, hills, and basins intersecting, making the development and utilization of land resources extremely difficult. On the contrary, along with problems such as ecological environmental pollution, soil erosion and land desertification have occurred in many parts of China, resulting in a decreasing trend of high-quality and high-yield land available for use. On the other hand, with the acceleration of the urbanization and industrialization processes, various types of construction not only occupy a large amount of land, but also cause soil pollution in a certain range. Especially the soil around mining areas and industrial sites often shows the loss of beneficial components, the accumulation of harmful components, the decline of soil fertility, and even soil environmental pollution caused by the accumulation of some heavy metals and organic pollutants.

[0003] If the polluted land, desertified land, salinized land, mined and damaged land, and land occupied by yards can be repaired and restored, it will undoubtedly be of great significance to tap the potential of cultivated land in China and ensure the sustainable development of the national economy. Research results show that whether it is the soil disturbed and damaged by mining, or sandy soil, saline soil, polluted soil, and coal gangue piles, there are more or less problems such as abnormal salinity, acidity, and alkalinity values of the soil, or abnormal contents of heavy metals and organic pollutants, and low contents of some soil nutrient components. When carrying out ecological restoration, it is usually necessary to take soil from other places for covering or use these external soils for soil improvement. For saline and polluted soils, in addition to taking soil from other places for covering and implementing soil improvement with external soils, it is also necessary to improve or transform the parent material layer or even the substrate layer, which means that in addition to taking soil from other places, a certain amount of large-particle materials such as sand and gravel are also needed.

[0004] Therefore, in order to carry out ecological restoration, it is necessary to quarry, dig sand, and take soil from other places over long distances, which not only increases the treatment cost, but also because these external soils and sand and gravel often need a certain process of improvement and domestication to adapt to the local soil. In this case, considering that coal gangue comes from coal-bearing strata and has homology with local rock and soil layers, and its composition and properties are similar, if coal gangue can be used for the ecological restoration of the soil in mining areas and their surrounding areas, it can not only avoid the problem that the external sand and soil are not suitable for the local restored soil and require a long time for domestication and improvement, but also realize the efficient resource utilization of coal gangue. Summary of the Invention

[0005] The object of the present invention is to provide a method for grading and separating coal gangue and an all-coal gangue ecological restoration method based on the grading and separating treatment of coal gangue. By implementing the grading and separating treatment of coal gangue, coal, crushed stones, manufactured sand, and soil are obtained. Based on the homology and easy mutual adaptation of soil, manufactured sand, and crushed stones with local rock formations and soil, they are used for local ecological restoration, thereby avoiding the complex domestication and improvement links required for obtaining sand and soil from outside, reducing the cost of ecological restoration, and improving the effect of ecological restoration.

[0006] In order to achieve the above-mentioned invention object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for grading and separating coal gangue, comprising the following steps: performing crushing and screening treatment on coal gangue to obtain coal, crushed stones of different particle sizes, manufactured sand, and soil;

[0008] When the ash content of the coal gangue is higher than 80 wt%, the crushing and screening treatment includes: screening the coal gangue using a sieve mesh with a pore size of 1 mm to obtain a first oversize of +1 mm and coal of -1 mm; performing multi-stage crushing and screening on the first oversize, and recovering coal of -1 mm each time of screening until the ash content of the oversize of +1 mm reaches more than 86 wt%; performing crushing on the obtained oversize and then screening it through a multi-layer sieve with sieve holes of 31.5 mm, 15 mm, 10 mm, 5 mm, and 2 mm to obtain crushed stones of +31.5 mm, -31.5 to +15 mm, -15 to +10 mm, and -10 to +5 mm, manufactured sand of -5 to +2 mm, and soil of -2 mm;

[0009] When the ash content of the coal gangue is less than or equal to 80 wt%, the crushing and screening treatment includes: screening the coal gangue using a sieve mesh with a pore size of 1 mm to obtain a second oversize of +1 mm and coal of -1 mm; performing primary crushing on the second oversize and screening it using sieve meshes with pore sizes of 31.5 mm and 1 mm to obtain crushed stones of +31.5 mm, a third oversize of -31.5 to +1 mm, and coal of -1 mm; performing secondary crushing on the third oversize and screening it using sieve meshes with pore sizes of 15 mm and 1 mm to obtain crushed stones of -31.5 to +15 mm, a fourth oversize of -15 to +1 mm, and coal of -1 mm; performing tertiary crushing on the fourth oversize and screening it using sieve meshes with pore sizes of 10 mm and 1 mm to obtain crushed stones of -15 to +10 mm, a fifth oversize of -10 to +1 mm, and coal of -1 mm; performing quaternary crushing on the fifth oversize and screening it using sieve meshes with pore sizes of 5 mm and 2 mm to obtain crushed stones of -10 to +5 mm, manufactured sand of -5 to +2 mm, and soil of -2 mm.

[0010] Preferably, the mass percentages of SiO2 and Al2O3 in the ash composition of the coal gangue are between 1.35 and 2.85; the content of K2O in the ash composition of the coal gangue is ≥ 1.05 wt%; the content of P2O5 in the ash composition of the coal gangue is ≥ 0.05 wt%.

[0011] The present invention provides an all-coal gangue ecological restoration method based on hierarchical and quality-separated treatment of coal gangue, comprising the following steps:

[0012] Lay one or several layers of the base layer, the regenerated soil layer and the topsoil layer on the soil to be restored for ecological restoration;

[0013] The base layer comprises crushed stones and manufactured sand of different particle sizes described in the above technical solution; in terms of mass percentage, the particle size gradation of the crushed stones and manufactured sand of different particle sizes is as follows: crushed stones of +31.5 mm account for 10 - 20%, crushed stones of -31.5 to +15 mm account for 12 - 20%, crushed stones of -15 to +10 mm account for 20 - 30%, crushed stones of -10 to +5 mm account for 15 - 25%, and manufactured sand of -5 to +2 mm accounts for 20 - 35%;

[0014] The regenerated soil layer comprises the soil of -2 mm described in the above technical solution;

[0015] The topsoil layer comprises the soil of -2 mm and auxiliary materials described in the above technical solution; the auxiliary materials include one or several of fallen leaves, turf, lignite, weathered coal and separated coal from coal gangue.

[0016] Preferably, the total porosity of the base layer is 35 - 45%.

[0017] Preferably, the organic matter content of the regenerated soil layer is 0.5 - 4.5 wt%; the pH value of the regenerated soil layer is neutral; the permeability of the regenerated soil layer does not exceed 2.267 mm / min.

[0018] Preferably, in terms of mass percentage, the particle size gradation of the regenerated soil layer is as follows: materials of -2.00 to +1.00 mm account for 0.5 - 5.0%, materials of -1.00 to +0.50 mm account for 5 - 15%, materials of -0.50 to +0.25 mm account for 10 - 25%, materials of -0.25 to +0.10 mm account for 25 - 35%, materials of -0.10 to +0.05 mm account for 15 - 20%, materials of -0.05 to +0.002 mm account for 5 - 15%, and materials of -0.002 mm account for 1 - 5%.

[0019] Preferably, when the auxiliary materials are a mixture of fallen leaves, turf, lignite, weathered coal, and coal gangue separated coal, the mass ratio of the fallen leaves, turf, lignite, weathered coal, and coal gangue separated coal is 10-20:15-25:15-25:10-20:25-40.

[0020] Preferably, the mass ratio of the soil with a particle size of -2 mm or less in the topsoil layer to the auxiliary materials is 85-95:5-15.

[0021] Preferably, the organic matter content of the topsoil layer is 0.5-10 wt%; the pH value of the topsoil layer is neutral or weakly acidic; the permeability of the topsoil layer does not exceed 3.467 mm / min.

[0022] Preferably, by mass percentage, the particle size distribution of the topsoil layer is as follows: materials with a particle size of -2.00 to +1.00 mm account for 1-10%, materials with a particle size of -1.00 to +0.50 mm account for 5-15%, materials with a particle size of -0.50 to +0.25 mm account for 10-25%, materials with a particle size of -0.25 to +0.10 mm account for 20-35%, materials with a particle size of -0.10 to +0.05 mm account for 15-25%, materials with a particle size of -0.05 to +0.002 mm account for 5-15%, and materials with a particle size of -0.002 mm account for 1-10%.

[0023] The present invention provides a method for classifying and separating coal gangue by quality, comprising the following steps: performing crushing and screening on coal gangue to obtain coal, crushed stones with different particle sizes, machine-made sand, and soil. The present invention uses local coal gangue. Based on its homology with rock strata and soil layers, coal gangue is first classified and separated by quality to obtain crushed stones, machine-made sand, and soil for ecological restoration, which can eliminate the need for complex domestication and improvement processes for sand and soil extraction from other places for ecological restoration, reduce the cost of ecological restoration, and improve the effect of ecological restoration. At the same time, the separated coal can be used as fuel, and some high-ash coal is used as auxiliary materials for the topsoil layer. Specific embodiments

[0024] The present invention provides a method for classifying and separating coal gangue by quality, comprising the following steps: performing crushing and screening on coal gangue to obtain coal, crushed stones with different particle sizes, machine-made sand, and soil;

[0025] When the ash content of the coal gangue is higher than 80 wt%, the crushing and screening treatment includes: screening the coal gangue with a sieve mesh with a pore size of 1 mm to obtain a first oversize of +1 mm and coal of -1 mm; performing multi-stage crushing and screening on the first oversize, recycling coal of -1 mm each time of screening until the ash content of the oversize of +1 mm reaches more than 86 wt%; crushing the obtained oversize and then screening it through multi-layer sieves with sieve holes of 31.5 mm, 15 mm, 10 mm, 5 mm and 2 mm to obtain crushed stones of +31.5 mm, -31.5 to +15 mm, -15 to +10 mm and -10 to +5 mm, manufactured sand of -5 to +2 mm and soil of -2 mm;

[0026] When the ash content of the coal gangue is less than or equal to 80 wt%, the crushing and screening treatment includes: screening the coal gangue with a sieve mesh with a pore size of 1 mm to obtain a second oversize of +1 mm and coal of -1 mm; performing primary crushing on the second oversize and screening it with sieve meshes with pore sizes of 31.5 mm and 1 mm to obtain crushed stones of +31.5 mm, a third oversize of -31.5 to +1 mm and coal of -1 mm; performing secondary crushing on the third oversize and screening it with sieve meshes with pore sizes of 15 mm and 1 mm to obtain crushed stones of -31.5 to +15 mm, a fourth oversize of -15 to +1 mm and coal of -1 mm; performing tertiary crushing on the fourth oversize and screening it with sieve meshes with pore sizes of 10 mm and 1 mm to obtain crushed stones of -15 to +10 mm, a fifth oversize of -10 to +1 mm and coal of -1 mm; performing quaternary crushing on the fifth oversize and screening it with sieve meshes with pore sizes of 5 mm and 2 mm to obtain crushed stones of -10 to +5 mm, manufactured sand of -5 to +2 mm and soil of -2 mm.

[0027] In the present invention, "+" in the particle size means greater than or equal to, and "-" means less than; taking "crushed stones of -31.5 to +15 mm" as an example, it means that the particle size of the crushed stones is less than 31.5 mm and greater than or equal to 15 mm.

[0028] In the present invention, when the ash content of the coal gangue is less than or equal to 80 wt%, after performing primary crushing on the second oversize, it further includes: screening it with sieve meshes with pore sizes of 50 mm and 1 mm to obtain crushed stones of +50 mm, an oversize of -50 to +1 mm and coal of -1 mm; crushing the oversize of -50 to +1 mm and then screening it with sieve meshes with pore sizes of 31.5 mm and 1 mm.

[0029] In the present invention, the mass percentages of SiO2 and Al2O3 in the ash composition of the coal gangue are preferably between 1.35 and 2.85; the content of K2O in the ash composition of the coal gangue is preferably ≥ 1.05 wt%, more preferably ≥ 1.00 wt%; the content of P2O5 in the ash composition of the coal gangue is preferably ≥ 0.05 wt%, more preferably ≥ 0.10 wt%.

[0030] In the present invention, the particle size of the coal is -1 mm.

[0031] The present invention provides an ecological restoration method for all coal gangue, comprising the following steps:

[0032] Lay one or several layers of the base layer, the regenerated soil layer and the topsoil layer on the soil to be restored for ecological restoration;

[0033] The base layer comprises crushed stones and manufactured sand of different particle sizes as described in the above technical solution; by mass percentage, the particle size gradation of the crushed stones and manufactured sand of different particle sizes is: crushed stones of +31.5 mm account for 10 - 20%, crushed stones of -31.5 to +15 mm account for 12 - 20%, crushed stones of -15 to +10 mm account for 20 - 30%, crushed stones of -10 to +5 mm account for 15 - 25%, and manufactured sand of -5 to +2 mm accounts for 20 - 35%;

[0034] The regenerated soil layer comprises the soil of -2 mm as described in the above technical solution;

[0035] The topsoil layer comprises the soil of -2 mm and auxiliary materials as described in the above technical solution; the auxiliary materials include one or several of fallen leaves, turf, lignite, weathered coal and separated coal of coal gangue.

[0036] In the present invention, the soil to be restored preferably comprises soil damaged by mining disturbance, desertified soil, salinized soil, polluted soil or coal gangue mountain. In the present invention, when the soil to be restored is soil damaged by mining disturbance, desertified soil or coal gangue mountain, it is preferred to lay the regenerated soil layer and the topsoil layer on the soil to be restored; when the soil to be restored is salinized soil or polluted soil, it is preferred to lay the base layer, the regenerated soil layer and the topsoil layer on the soil to be restored in sequence.

[0037] In the present invention, the thickness of the base layer is preferably 300 - 450 mm, more preferably 400 - 450 mm. In the present invention, the total porosity (ε) of the base layer is preferably 35 - 45%. In the present invention, by mass percentage, the particle size gradation of the base layer is preferably: crushed stones of +31.5 mm account for 10 - 13%, crushed stones of -31.5 to +15 mm account for 14 - 15%, crushed stones of -15 to +10 mm account for 22 - 25%, crushed stones of -10 to +5 mm account for 25%, and manufactured sand of -5 to +2 mm accounts for 25 - 28%.

[0038] In the present invention, the thickness of the regenerated soil layer is preferably 125 - 300 mm, more preferably 250 - 300 mm. In the present invention, the organic matter content of the regenerated soil layer is preferably 0.5 - 4.5 wt%, more preferably 0.55 - 3.5 wt%; the pH value of the regenerated soil layer is preferably neutral, specifically preferably 7.05 - 7.50; the permeability of the regenerated soil layer is preferably not more than 2.267 mm / min, more preferably 1.167 - 2.267 mm / min, specifically preferably 1.169 - 2.065 mm / min.

[0039] In the present invention, by mass percentage, the particle size distribution of the regenerated soil layer is preferably as follows: materials with -2.00 to +1.00 mm account for 0.5 - 5.0%, materials with -1.00 to +0.50 mm account for 5 - 15%, materials with -0.50 to +0.25 mm account for 10 - 25%, materials with -0.25 to +0.10 mm account for 25 - 35%, materials with -0.10 to +0.05 mm account for 15 - 20%, materials with -0.05 to +0.002 mm account for 5 - 15%, and materials with -0.002 mm account for 1 - 5%. In the present invention, by mass percentage, the particle size distribution of the regenerated soil layer is more preferably as follows: materials with -2.00 to +1.00 mm account for 1 - 4%, materials with -1.00 to +0.50 mm account for 5 - 14%, materials with -0.50 to +0.25 mm account for 11 - 18%, materials with -0.25 to +0.10 mm account for 25.5 - 31%, materials with -0.10 to +0.05 mm account for 15.5 - 17%, materials with -0.05 to +0.002 mm account for 5 - 14%, and materials with -0.002 mm account for 1.5 - 5%.

[0040] In the present invention, the thickness of the topsoil layer is preferably 100 - 150 mm, more preferably 100 - 145 mm. In the present invention, the mass ratio of soil with -2 mm and auxiliary materials in the topsoil layer is preferably 85 - 95:5 - 15, more preferably 90 - 95:5 - 10. In the present invention, when the auxiliary materials are a mixture of fallen leaves, sod, lignite, weathered coal, and coal gangue separated coal, the mass ratio of fallen leaves, sod, lignite, weathered coal, and coal gangue separated coal is preferably 10 - 20:15 - 25:15 - 25:10 - 20:25 - 40. In the present invention, the particle sizes of the fallen leaves and sod are preferably independently less than 10 mm; the particle sizes of the lignite, weathered coal, and coal gangue separated coal are preferably less than 2 mm. In the present invention, the coal gangue separated coal is more preferably the -1 mm coal obtained by the above-mentioned classification and quality separation of coal gangue.

[0041] In the present invention, the organic matter content of the topsoil is preferably 0.5 - 10 wt%, more preferably 0.55 - 8.5 wt%, and specifically preferably 0.59 - 8.00 wt%; the pH value of the topsoil is preferably slightly acidic to slightly alkaline, and specifically preferably 6.45 - 8.15; the permeability of the topsoil is preferably not more than 3.467 mm / min, more preferably 1.333 - 3.467 mm / min, and specifically preferably 1.367 - 3.333 mm / min. In the present invention, the available phosphorus content of the topsoil is preferably not less than 0.078 g / kg, the total nitrogen content is preferably not less than 0.185 g / kg, and the available potassium content is preferably not less than 0.125 g / kg.

[0042] In the present invention, by mass percentage, the particle size distribution of the topsoil is preferably as follows: materials with -2.00 to +1.00 mm account for 1 - 10%, materials with -1.00 to +0.50 mm account for 5 - 15%, materials with -0.50 to +0.25 mm account for 10 - 25%, materials with -0.25 to +0.10 mm account for 20 - 35%, materials with -0.10 to +0.05 mm account for 15 - 25%, materials with -0.05 to +0.002 mm account for 5 - 15%, and materials with -0.002 mm account for 1 - 10%.

[0043] In the present invention, by mass percentage, the particle size distribution of the topsoil is more preferably as follows: materials with -2.00 to +1.00 mm account for 1.5 - 5%, materials with -1.00 to +0.50 mm account for 5 - 14%, materials with -0.50 to +0.25 mm account for 11 - 18%, materials with -0.25 to +0.10 mm account for 21 - 32%, materials with -0.10 to +0.05 mm account for 15.5 - 18%, materials with -0.05 to +0.002 mm account for 10 - 14%, and materials with -0.002 mm account for 6 - 9%.

[0044] In a specific embodiment of the present invention, when starting ecological restoration, ground cover plants are planted on the topsoil. After 1 - 2 growth cycles, it is changed to planting fruit trees or fruit and vegetable crops for ecological restoration and soil restoration. In the present invention, the ground cover plants are preferably alfalfa or iris plants, etc.

[0045] In the present invention, the organic matter content of the restored soil is preferably not less than 1.47 wt%, the pH value is preferably 6.45 - 7.85, the available phosphorus content is preferably not less than 0.085 g / kg, the total nitrogen content is preferably not less than 0.190 g / kg, and the available potassium content is preferably not less than 0.130 g / kg.

[0046] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0047] Example 1

[0048] In response to the disturbance and damage of the soil caused by mine exploitation, coal gangue with an ash content (Ad) of 81.5 wt% is used for restoration:

[0049] Screening is carried out using a relaxation screen (S1) with a screen hole of 1 mm. The materials with -1 mm are used as coal for recovery, and the materials with +1 mm are subjected to multi-stage crushing, and then screened again by S1 until the ash content of the +1 mm materials reaches 86.15%, and no longer recover the coal with -1 mm; then it is crushed again, and then enters a multi-layer screen with screen holes of 31.5 mm, 15 mm, 10 mm, 5 mm and 2 mm for screening, obtaining crushed stones with +31.5 mm, -31.5 to +15 mm, -15 to +10 mm and -10 to +5 mm, manufactured sand with -5 to +2 mm, and soil with -2 mm.

[0050] Using the soil with -2 mm to form a 250 mm thick regenerated soil layer. The organic matter content of the regenerated soil layer is 1.05 wt%, and the pH value is 7.45; the permeability of the regenerated soil layer is 1.169 mm / min; by mass percentage, the particle size distribution of the regenerated soil layer is: -2.00 to +1.00 mm: -1.00 to +0.50 mm: -0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 4%: 12.5%: 18%: 30%: 17.5%: 13.5%: 4.5%.

[0051] Mix the soil with -2 mm and fallen leaves in a mass percentage of 92.5%: 7.5% to form a 125 mm thick topsoil layer. The organic matter content of the topsoil layer is 5.05 wt%; the pH value is 6.80; the available phosphorus content is 0.093 g / kg; the total nitrogen content is 0.206 g / kg; the available potassium content is 0.136 g / kg; the permeability of the topsoil layer is 2.333 mm / min; by mass percentage, the particle size distribution of the topsoil layer is: -2.00 to +1.00 mm: -1.00 to +0.50 mm: -0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 5%: 13%: 16%: 32%: 20%: 8%: 6%.

[0052] Arrange the above-mentioned regenerated soil layer and topsoil layer in sequence on the soil surface damaged by mining disturbance in the mine for ecological restoration. After planting alfalfa for 1 year, the soil quality of the topsoil layer reaches: organic matter content is 4.89 wt%; pH value is 7.15; available phosphorus content is 0.139 g / kg; total nitrogen content is 0.287 g / kg; available potassium content is 0.236 g / kg; relevant crops can be planted.

[0053] Example 2

[0054] For the desertified soil around the mining area, use coal gangue with ash content (Ad) of 72.39 wt% for restoration:

[0055] Screen with a relaxation screen (S1) with a screen hole of 1 mm. The materials with -1 mm are recovered as coal, and the materials with +1 mm are subjected to primary crushing, then screened with S1 again, and then enter a screen with a screen hole of 50 mm for screening; the materials with +50 mm are directly recovered as crushed stones; the materials with -50 to +1 mm enter secondary crushing, after screening with S1, the materials with -1 mm are used as coal, and then enter a screen with a screen hole of +31.5 mm for screening, and the materials with -50 to +31.5 mm are directly recovered as crushed stones; the materials with -31.5 to +1 mm enter tertiary crushing, after screening with S1, the materials with -1 mm are used as coal, and then screened with a screen with a screen hole of 15 mm, the materials with -31.5 to +15 mm are directly recovered as crushed stones, and the materials with -15 to +1 mm enter quaternary crushing, after screening with S1, the materials with -1 mm are used as coal, and then screened with a screen with a pore size of 10 mm, the formed materials with -15 to +10 mm are used as crushed stones, and the materials with -10 to +1 mm enter fifth crushing, and then screened with screens with pore sizes of 5 mm and 2 mm, the materials with -10 to +5 mm are used as crushed stones, the materials with -5 to +2 mm are used as machine-made sand, and the materials with -2 mm are used as soil.

[0056] Use the soil with -2 mm to form a regenerated soil layer of 250 mm. The organic matter content of the regenerated soil layer is 1.13 wt%, and the pH value is 7.49; the permeability of the regenerated soil layer is 1.123 mm / min; by mass percentage, the particle size distribution of the regenerated soil layer is -2.00 to +1.00 mm: -1.00 to +0.50 mm: 0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 4%: 13%: 17%: 30%: 18%: 13%: 5%.

[0057] Mix 2 mm of soil with sod at a mass percentage of 92%:8% to form a 150 mm topsoil layer. The organic matter content of the topsoil layer is 5.49 wt%; the pH value is 6.95; the available phosphorus content is 0.096 g / kg; the total nitrogen content is 0.195 g / kg; the available potassium content is 0.148 g / kg; the permeability of the topsoil layer is 3.333 mm / min; by mass percentage, the particle size distribution of the topsoil layer is as follows: -2.00 to +1.00 mm: -1.00 to +0.50 mm: -0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 5%:14%:16%:30%:21%:7%:7% after blending.

[0058] Arrange the regenerated soil layer and the topsoil layer in sequence on the surface of the desertified soil around the mining area for ecological restoration. After planting iris vegetation for 1 year, the soil quality of the topsoil layer reaches: the organic matter content is 4.55 wt%; the pH value is 7.13; the available phosphorus content is 0.118 g / kg; the total nitrogen content is 0.267 g / kg; the available potassium content is 0.249 g / kg, and relevant crops can be replanted.

[0059] Example 3

[0060] For the saline-alkali soil around the mining area, use coal gangue with an ash content (Ad) of 70.66 wt% for restoration:

[0061] Screen using a relaxation screen (S1) with a screen hole of 1 mm. The materials -1 mm are recovered as coal, and the materials +1 mm are subjected to primary crushing, then screened again with S1, and then screened through a screen mesh with a screen hole of 31.5 mm; the materials +31.5 mm are used as crushed stones; the materials -31.5 to +1 mm enter secondary crushing. After screening with S1, the materials -1 mm are used as coal, and then enter a screen mesh with a screen hole of 15 mm for screening. The materials -31.5 to +15 mm are used as crushed stones; the materials -15 to +1 mm enter tertiary crushing. After screening with S1, the materials -1 mm are used as coal, and then screened using a screen mesh with a screen hole of 10 mm. The materials -15 to +10 mm are used as crushed stones, and the materials -10 to +1 mm enter quaternary crushing, and then screened using screen meshes with apertures of 5 mm and 2 mm. The formed materials -10 to +5 mm are used as crushed stones, the materials -5 to +2 mm are used as machine-made sand, and the materials -2 mm are used as soil.

[0062] Mix crushed stones of +31.5mm, -31.5 to +15mm, -15 to +10mm, -10 to +5mm and manufactured sand of -5 to +2mm at a mass percentage of 13%:15%:22%:25%:25% to form a base layer with a thickness of 425mm;

[0063] Use soil of -2mm to form a 250mm thick regenerated soil layer. The organic matter content of the regenerated soil layer is 1.25wt%, and the pH value is 7.35; the permeability of the regenerated soil layer is 2.065mm / min; by mass percentage, the particle size distribution of the regenerated soil layer is: -2.00 to +1.00mm: -1.00 to +0.50mm: -0.50 to +0.25mm: -0.25 to +0.10mm: -0.10 to +0.05mm: -0.05 to +0.002mm: -0.002mm = 4%:12.5%:18%:32.5%:16%:12%:5%. Mix soil of -2mm and weathered coal at a mass percentage of 90%:10% to form a 125mm thick surface soil layer. The organic matter content of the surface soil layer is 4.47wt%; the pH value is 6.90; the available phosphorus content is 0.089g / kg; the total nitrogen content is 0.189g / kg; the available potassium content is 0.137g / kg; the permeability of the surface soil layer is 2.467mm / min; by mass percentage, the particle size distribution of the surface soil layer is: -2.00 to +1.00mm: -1.00 to +0.50mm: -0.50 to +0.25mm: -0.25 to +0.10mm: -0.10 to +0.05mm: -0.05 to +0.002mm: -0.002mm = 5%:13%:18%:31%:17%:9%:6%.

[0064] Arrange the base layer, the regenerated soil layer and the surface soil layer in sequence on the saline - alkali soil surface around the mining area for ecological restoration. After planting iris - like vegetation for 1 year, the soil quality of the surface soil layer reaches: the organic matter content is 4.57wt%; the pH value is 7.07; the available phosphorus content is 0.125g / kg; the total nitrogen content is 0.274g / kg; the available potassium content is 0.203g / kg, and relevant crops can be planted instead.

[0065] Example 4

[0066] For the organic - polluted soil around the mining area, use coal gangue with an ash content (Ad) of 82.96wt% for restoration:

[0067] Screening is carried out using a relaxation screen (S1) with a screen hole of 1 mm. Materials of -1 mm are recovered as coal, and materials of +1 mm are subjected to multi-stage crushing and then re-screened by S1 until the ash content of the +1 mm materials reaches 86.56%, and coal of -1 mm is no longer recovered. Then, further crushing is carried out, and then it enters a multi-layer screen with screen holes of 31.5 mm, 15 mm, 10 mm, 5 mm, and 2 mm for screening, obtaining crushed stones of +31.5 mm, -31.5~+15 mm, -15~+10 mm, and -10~+5 mm, manufactured sand of -5~+2 mm, and soil of -2 mm.

[0068] After mixing the crushed stones of +31.5 mm, -31.5~+15 mm, -15~+10 mm, -10~+5 mm and the manufactured sand of -5~+2 mm according to the mass percentage of 10%:15%:22%:25%:28%, a base layer with a thickness of 425 mm is formed;

[0069] A 250-mm regenerated soil layer is formed using soil of -2 mm. The organic matter content of the regenerated soil layer is 1.45 wt%, and the pH value is 7.45; the permeability of the regenerated soil layer is 1.667 mm / min; by mass percentage, the particle size distribution of the regenerated soil layer is -2.00~+1.00 mm: -1.00~+0.50 mm: 0.50~+0.25 mm: -0.25~+0.10 mm: -0.10~+0.05 mm: 0.05~+0.002 mm: -0.002 mm = 3.5%: 12.5%: 17%: 31.5%: 17.5%: 13.5%: 4.5%.

[0070] After mixing the soil of -2 mm and low-rank lignite according to the mass percentage of 91%:9%, a 115-mm topsoil layer is formed. The organic matter content of the topsoil layer is 5.62 wt%; the pH value is 6.86; the available phosphorus content is 0.115 g / kg; the total nitrogen content is 0.253 g / kg; the available potassium content is 0.156 g / kg; the permeability of the topsoil layer is 2.467 mm / min; by mass percentage, the particle size distribution of the topsoil layer is: -2.00~+1.00 mm: -1.00~+0.50 mm: -0.50~+0.25 mm: -0.25~+0.10 mm: -0.10~+0.05 mm: -0.05~+0.002 mm: -0.002 mm = 4.5%: 12.5%: 18%: 32%: 18%: 9%: 6%.

[0071] For ecological restoration, the base layer, the regenerated soil layer, and the topsoil layer are sequentially arranged on the surface of the organically polluted soil around the mining area. After planting iris vegetation for 1 year, the soil quality of the topsoil layer reaches: organic matter content is 4.78 wt%; pH value is 7.17; available phosphorus content is 0.133 g / kg; total nitrogen content is 0.307 g / kg; available potassium content is 0.226 g / kg, and relevant crops can be planted instead.

[0072] Example 5

[0073] For the heavy metal Hg-polluted soil around the mining area, coal gangue with an ash content (Ad) of 75.46 wt% is used for remediation:

[0074] Screening is carried out using a sieve mesh (S1) with a sieve hole of 1 mm. The materials with a size of -1 mm are recovered as coal, and the materials with a size of +1 mm are subjected to primary crushing, then screened again with S1, and then enter a sieve mesh with a sieve hole of 50 mm for screening; the materials with a size of +50 mm are directly recovered as crushed stones; the materials with a size of -50 to +1 mm enter secondary crushing, and after screening with S1, the materials with a size of -1 mm are used as coal, and then enter a sieve mesh with a sieve hole of +31.5 mm for screening. The materials with a size of -50 to +31.5 mm are directly recovered as crushed stones; the materials with a size of -31.5 to +1 mm enter tertiary crushing, and after screening with S1, the materials with a size of -1 mm are used as coal, and then screened using a sieve mesh with a sieve hole of 15 mm. The materials with a size of -31.5 to +15 mm are directly recovered as crushed stones, and the materials with a size of -15 to +1 mm enter quaternary crushing. After screening with S1, the materials with a size of -1 mm are used as coal, and then screened using a sieve mesh with a pore diameter of 10 mm. The formed materials with a size of -15 to +10 mm are used as crushed stones, and the materials with a size of -10 to +1 mm enter fifth-stage crushing, and then screened using sieve meshes with pore diameters of 5 mm and 2 mm. The materials with a size of -10 to +5 mm are used as crushed stones, the materials with a size of -5 to +2 mm are used as manufactured sand, and the materials with a size of -2 mm are used as soil.

[0075] After mixing the crushed stones with sizes of +31.5 mm, -31.5 to +15 mm, -15 to +10 mm, and -10 to +5 mm and the manufactured sand with a size of -5 to +2 mm according to a mass ratio of 11%:14%:25%:25%:25%, a base layer with a thickness of 425 mm is formed;

[0076] Using soil with a particle size of -2 mm to form a 250-mm thick regenerated soil layer, the organic matter content of the regenerated soil layer is 1.23 wt%, the pH value is 7.55; the permeability of the regenerated soil layer is 1.567 mm / min; by mass percentage, the particle size distribution of the regenerated soil layer is: -2.00 to +1.00 mm: -1.00 to +0.50 mm: 0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 3.5%: 12.5%: 16.5%: 32.5%: 16.5%: 14.5%: 4%.

[0077] Mix soil with a particle size of -2 mm and weathered coal in a mass percentage of 90:10 to form a 125-mm thick topsoil layer. The organic matter content of the topsoil layer is 4.72 wt%; the pH value is 6.85; the available phosphorus content is 0.109 g / kg; the total nitrogen content is 0.269 g / kg; the available potassium content is 0.163 g / kg; the permeability of the topsoil layer is 2.167 mm / min; by mass percentage, the particle size distribution of the topsoil layer is: -2.00 to +1.00 mm: -1.00 to +0.50 mm: -0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 4%: 12%: 17%: 32%: 18%: 10%: 7%.

[0078] Ecological restoration is carried out by arranging the base layer, the regenerated soil layer and the topsoil layer in sequence on the surface of heavy metal Hg-polluted soil around the mining area. After planting iris vegetation for 1 year, the soil quality of the topsoil layer reaches: the organic matter content is 4.98 wt%; the pH value is 7.03; the available phosphorus content is 0.123 g / kg; the total nitrogen content is 0.276 g / kg; the available potassium content is 0.163 g / kg, and relevant crops can be planted instead.

[0079] Example 6

[0080] For the coal gangue mountain in the mine, coal gangue with an ash content (Ad) of 76.94 wt% is used for restoration:

[0081] Screening is carried out using a sieve mesh (S1) with a sieve pore of 1 mm. Materials of -1 mm are recovered as coal, and materials of +1 mm are subjected to primary crushing, then screened again with S1, and then enter a sieve mesh with a sieve pore of 31.5 mm for screening; materials of +31.5 mm are directly recovered as crushed stones; materials of -31.5 to +1 mm enter secondary crushing. After screening with S1, materials of -1 mm are used as coal, and then enter a sieve mesh with a sieve pore of 15 mm for screening. Materials of -31.5 to +15 mm are directly recovered as crushed stones; materials of -15 to +1 mm enter tertiary crushing. After screening with S1, materials of -1 mm are used as coal, and then screened using a sieve mesh with a sieve pore of 10 mm. Materials of -15 to +10 mm are directly recovered as crushed stones; materials of -10 to +1 mm enter quaternary crushing, and then are screened using sieve meshes with pore sizes of 5 mm and 2 mm. Materials of -10 to +5 mm are used as crushed stones, materials of -5 to +2 mm are used as manufactured sand, and materials of -2 mm are used as soil.

[0082] Using the soil of -2 mm to form a 250-mm thick regenerated soil layer, the organic matter content of the regenerated soil layer is 1.165%, and the pH value is 7.50; the permeability of the regenerated soil layer is 1.576 mm / min; by mass percentage, the particle size distribution of the regenerated soil layer is -2.00 to +1.00 mm: -1.00 to +0.50 mm: 0.50 to +0.25 mm: -0.25 to +0.10 mm: -0.10 to +0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 3%: 12.5%: 15.5%: 31.5%: 19%: 13.5%: 5%.

[0083] Mixing the soil of -2 mm and the separated coal in a mass percentage of 90.5%: 9.5% to form a 125-mm thick topsoil layer. The organic matter content of the topsoil layer is 5.78 wt%; the pH value is 6.56; the available phosphorus content is 0.109 g / kg; the total nitrogen content is 0.263 g / kg; the available potassium content is 0.166 g / kg; the permeability of the topsoil layer is 2.467 mm / min; by mass percentage, the particle size distribution of the topsoil layer is: -2.00 to +1.00 mm: -1.00 to +0.50 mm: -0.50 to +0.25 mm: -0.25 to +0.10 mm: 0.10 to 0.05 mm: -0.05 to +0.002 mm: -0.002 mm = 5%: 13%: 18%: 31%: 17%: 10%: 6%.

[0084] The regenerated soil layer and the topsoil layer are sequentially arranged on the surface of the mine coal gangue mountain for ecological restoration. After planting iris vegetation for 1 year, the soil quality of the topsoil layer reaches: the organic matter content is 4.77 wt%; the pH value is 8.01; the available phosphorus content is 0.159 g / kg; the total nitrogen content is 0.317 g / kg; the available potassium content is 0.235 g / kg, and it can be changed to plant relevant crops.

[0085] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An all-coal gangue ecological restoration method based on the classified and quality-separated treatment of coal gangue, comprising the following steps: Laying one or several of a base layer, a regenerated soil layer, and a topsoil layer on the soil to be restored for ecological restoration; The base layer includes crushed stones and manufactured sand of different particle sizes; by mass percentage, the particle size gradation of the crushed stones and manufactured sand of different particle sizes is: crushed stones with a particle size of +31.5 mm account for 10-20%, crushed stones with a particle size of -31.5 to +15 mm account for 12-20%, crushed stones with a particle size of -15 to +10 mm account for 20-30%, crushed stones with a particle size of -10 to +5 mm account for 15-25%, and manufactured sand with a particle size of -5 to +2 mm accounts for 20-35%; The regenerated soil layer includes soil with a particle size of -2 mm; The topsoil layer includes soil with a particle size of -2 mm and auxiliary materials; the auxiliary materials include one or several of fallen leaves, turf, lignite, weathered coal, and separated coal from coal gangue; The crushed stones, manufactured sand, and soil of different particle sizes are obtained by classifying and separating the coal gangue, and the classification and separation include the following steps: crushing and screening the coal gangue to obtain coal, crushed stones of different particle sizes, manufactured sand, and soil; When the ash content of the coal gangue is higher than 80 wt%, the crushing and screening treatment includes: screening the coal gangue with a sieve mesh with a pore size of 1 mm to obtain a first oversize material with a particle size of +1 mm and coal with a particle size of -1 mm; performing multi-stage crushing and screening on the first oversize material, and recovering coal with a particle size of -1 mm each time until the ash content of the oversize material with a particle size of +1 mm reaches more than 86 wt%; crushing the obtained oversize material and then screening it through multi-layer sieves with sieve holes of 31.5 mm, 15 mm, 10 mm, 5 mm, and 2 mm to obtain crushed stones with a particle size of +31.5 mm, -31.5 to +15 mm, -15 to +10 mm, and -10 to +5 mm, manufactured sand with a particle size of -5 to +2 mm, and soil with a particle size of -2 mm; When the ash content of the coal gangue is less than or equal to 80 wt%, the crushing and screening treatment includes: screening the coal gangue with a sieve mesh with a pore size of 1 mm to obtain a second oversize material with a particle size of +1 mm and coal with a particle size of -1 mm; performing primary crushing on the second oversize material and screening it with sieve meshes with pore sizes of 31.5 mm and 1 mm to obtain crushed stones with a particle size of +31.5 mm, a third oversize material with a particle size of -31.5 to +1 mm, and coal with a particle size of -1 mm; performing secondary crushing on the third oversize material and screening it with sieve meshes with pore sizes of 15 mm and 1 mm to obtain crushed stones with a particle size of -31.5 to +15 mm, a fourth oversize material with a particle size of -15 to +1 mm, and coal with a particle size of -1 mm; performing tertiary crushing on the fourth oversize material and screening it with sieve meshes with pore sizes of 10 mm and 1 mm to obtain crushed stones with a particle size of -15 to +10 mm, a fifth oversize material with a particle size of -10 to +1 mm, and coal with a particle size of -1 mm; performing quaternary crushing on the fifth oversize material and screening it with sieve meshes with pore sizes of 5 mm and 2 mm to obtain crushed stones with a particle size of -10 to +5 mm, manufactured sand with a particle size of -5 to +2 mm, and soil with a particle size of -2 mm.

2. The all-coal gangue ecological restoration method according to claim 1, wherein The mass percentages of SiO2 and Al2O3 in the ash composition of the coal gangue are between 1.35 and 2.85; the content of K2O in the ash composition of the coal gangue is ≥1.05 wt%; the content of P2O5 in the ash composition of the coal gangue is ≥0.05 wt%.

3. The all-coal gangue ecological restoration method according to claim 1, wherein The total porosity of the base layer is 35-45%.

4. The all-coal gangue ecological restoration method according to claim 1, characterized in that, The organic matter content of the regenerated soil layer is 0.5-4.5 wt%; the pH value of the regenerated soil layer is neutral; the permeability of the regenerated soil layer does not exceed 2.267 mm / min.

5. The all-coal gangue ecological restoration method according to claim 1 or 4, characterized in that, By mass percentage, the particle size distribution of the regenerated soil layer is as follows: materials with -2.00 to +1.00 mm account for 0.5-5.0%, materials with -1.00 to +0.50 mm account for 5-15%, materials with -0.50 to +0.25 mm account for 10-25%, materials with -0.25 to +0.10 mm account for 25-35%, materials with -0.10 to +0.05 mm account for 15-20%, materials with -0.05 to +0.002 mm account for 5-15%, and materials with -0.002 mm account for 1-5%.

6. The all-coal gangue ecological restoration method according to claim 1, characterized in that When the auxiliary materials are a mixture of fallen leaves, sod, lignite, weathered coal, and separated coal from coal gangue, the mass ratio of the fallen leaves, sod, lignite, weathered coal, and separated coal from coal gangue is 10-20:15-25:15-25:10-20:25-40.

7. The all-coal gangue ecological restoration method according to claim 1 or 6, characterized in that The mass ratio of the soil with -2 mm and the auxiliary materials in the topsoil layer is 85-95:5-15.

8. The all-coal gangue ecological restoration method according to claim 1, wherein, The organic matter content of the topsoil layer is 0.5-10 wt%; the pH value of the topsoil layer is neutral or weakly acidic; the permeability of the topsoil layer does not exceed 3.467 mm / min.

9. The all-coal gangue ecological restoration method according to claim 1, characterized in that By mass percentage, the particle size distribution of the topsoil layer is as follows: materials with -2.00 to +1.00 mm account for 1-10%, materials with -1.00 to +0.50 mm account for 5-15%, materials with -0.50 to +0.25 mm account for 10-25%, materials with -0.25 to +0.10 mm account for 20-35%, materials with -0.10 to +0.05 mm account for 15-25%, materials with -0.05 to +0.002 mm account for 5-15%, and materials with -0.002 mm account for 1-10%.