A method for the comprehensive utilization of all components of coal gangue by grading and quality separation

Abstract

The present invention provides a method for the comprehensive utilization of coal gangue by grading and separating different components, which relates to the technical field of resource utilization of solid waste. Based on the differences in the component composition and technological properties of coal gangue, especially based on the different mass content ratios of SiO2 / Al2O3 in coal gangue, different crushing and screening processes are adopted respectively. Through multi-stage crushing, precise grading and separation technologies, the coal, gangue (soil) and stone in coal gangue are separated and sorted to obtain crushed stones, manufactured sand, soil and coal with different particle sizes. Then, according to their respective compositional and technological property differences, fuel utilization, recycled soil utilization, fertilizer preparation utilization and CO2 absorption and fixation material preparation utilization are carried out respectively, so as to realize the comprehensive utilization of coal gangue by grading and separating different components.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of solid waste, and particularly relates to a method for comprehensive utilization of different grades and qualities of coal gangue. Background Art

[0002] Due to different regions, coal-forming epochs, mining and washing methods, different coal gangues show variations in composition and properties, manifesting obvious heterogeneity. Obviously, the premise for effective resource utilization of coal gangue is to first implement homogenization treatment of coal gangue. In addition, at present, the processing and utilization of coal gangue at home and abroad regard coal gangue as a unified whole, rather than regarding coal gangue as a mixture of coal, gangue (soil) and stone, and taking targeted measures to separate the coal, gangue (soil) and stone in coal gangue and utilize them reasonably and effectively. After implementing selective crushing to separate different components in coal gangue, the coal can be used as fuel, the stone can be used to prepare sand and gravel building materials, and the soil can be used as raw material, so as to effectively implement the resource utilization of coal gangue. In addition, for the resource utilization of coal gangue, it is necessary to fully consider the economic development status and industrial policies of the country and localities, adopt measures according to local conditions and the characteristics of coal gangue, adhere to the principles of resource utilization, reduction and harmlessness, organically combine the general utilization and high-value utilization of coal gangue, organically combine the bulk utilization and high-value utilization of coal gangue, organically combine the conventional utilization and functional utilization of coal gangue, adopt differential targeted measures and precise processing methods, and overall consider the fuel utilization, building material utilization and material utilization of coal gangue, so as to effectively implement the comprehensive resource utilization of all components of coal gangue and achieve large-scale reduction and near-zero emission of coal gangue. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for comprehensive utilization of different grades and qualities of coal gangue to achieve homogenization treatment and effective resource utilization of coal gangue.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a method for comprehensive utilization of different grades and qualities of coal gangue, including the following steps: performing crushing and screening on coal gangue to obtain crushed stones, machine-made sand, soil and coal with different particle sizes;

[0006] The crushing and screening process includes: performing primary crushing on the coal gangue, screening with sieves having apertures of 30 mm and 1 mm to obtain crushed stones of +30 mm, oversize materials of -30~+1 mm, and coal of -1 mm; performing secondary crushing on the oversize materials of -30~+1 mm, screening with sieves having apertures of 15 mm and 1 mm to obtain crushed stones of -30~+15 mm, oversize materials of -15~+1 mm, and coal of -1 mm; performing tertiary crushing on the oversize materials of -15~+1 mm, screening with sieves having apertures of 10 mm and 1 mm to obtain crushed stones of -15~+10 mm, oversize materials of -10~+1 mm, and coal of -1 mm; performing quaternary crushing on the oversize materials of -10~+1 mm, screening with sieves having apertures of 5 mm and 2 mm to obtain crushed stones of -10~+5 mm, manufactured sand of -5~+2 mm, and soil of less than -2 mm.

[0007] Preferably, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue > 1.95, a counterattack crusher is used for primary crushing, an impact crusher is used for secondary crushing, a hammer crusher is used for tertiary crushing; a fine-grained hammer crusher is used for quaternary crushing;

[0008] When the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue is greater than 1.25 and less than or equal to 1.95, a jaw crusher is used for primary crushing, a hammer crusher is used for secondary crushing, a cone crusher is used for tertiary crushing, and a fine-grained cone crusher is used for quaternary crushing;

[0009] When the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue ≤ 1.25 or the content of Al2O3 exceeds 37 wt%, a jaw crusher is used for primary crushing, a pair-roll crusher is used for secondary crushing, a cone crusher is used for tertiary crushing, and a fine-grained cone crusher is used for quaternary crushing.

[0010] Preferably, after the primary crushing, it further includes: screening with sieves having apertures of 50 mm and 1 mm to obtain crushed stones of +50 mm, oversize materials of -50~+1 mm, and coal of -1 mm; crushing the oversize materials of -50~+1 mm and then screening with sieves having apertures of 30 mm and 1 mm.

[0011] Preferably, the sieves used for screening include double-deck high-frequency vibrating screens or relaxation screens.

[0012] Preferably, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue > 1.25, partial separated soil of -5~+2 mm is also obtained, crushed to less than 2 mm and used as low-organic matter soil.

[0013] Preferably, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the gangue > 1.25, the separated soil with a particle size of -2 mm is used as medium-high organic matter soil.

[0014] Preferably, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the gangue ≤ 1.25 or the content of Al2O3 exceeds 37 wt%, the separated soil with a particle size of -5~+2 mm and the separated soil with a particle size of -2 mm are all crushed to less than 0.5 mm for flotation to recover coal and kaolin ore, and some intermediate products that are difficult to separate by flotation are used as medium-high organic matter soil.

[0015] Preferably, the soil with a CaO content ≥ 5 wt% obtained by classifying and separating limestone gangue is directly crushed to less than 3 mm to co-process coal-based solid waste and high-alkali waste residue to prepare a cement-free gelling material for CO2 absorption and mineralization.

[0016] The present invention provides a method for comprehensive utilization of gangue by classification and quality separation. Based on the compositional and property differences of different gangues, the present invention adopts multi-stage crushing, precise classification and separation technologies to separate coal, gangue (soil) and stone in the gangue, obtaining crushed stones, machine-made sand, soil and coal with different particle sizes, and respectively making reasonable and effective use of them to achieve the comprehensive resource utilization of gangue by classification and quality separation. Specific embodiments

[0017] The present invention provides a method for comprehensive utilization of gangue by classification and quality separation, including the following steps: performing crushing and screening treatment on the gangue to obtain crushed stones, machine-made sand, soil and coal with different particle sizes;

[0018] The crushing and screening treatment includes: performing primary crushing on the gangue and screening with sieves having apertures of 30 mm and 1 mm to obtain crushed stones with a particle size of +30 mm, the first oversize material with a particle size of -30~+1 mm, and coal with a particle size of -1 mm; performing secondary crushing on the first oversize material and screening with sieves having apertures of 15 mm and 1 mm to obtain crushed stones with a particle size of -30~+15 mm, the second oversize material with a particle size of -15~+1 mm, and coal with a particle size of -1 mm; performing tertiary crushing on the second oversize material and screening with sieves having apertures of 10 mm and 1 mm to obtain crushed stones with a particle size of -15~+10 mm, the third oversize material with a particle size of -10~+1 mm, and coal with a particle size of -1 mm; performing quaternary crushing on the third oversize material with a particle size of -10~+1 mm and screening with sieves having apertures of 5 mm and 2 mm to obtain crushed stones with a particle size of -10~+5 mm, machine-made sand with a particle size of -5~+2 mm, and soil with a particle size of less than -2 mm.

[0019] In the present invention, "+" in the particle size means greater than or equal to, and "-" means less than.

[0020] Preferably, after the primary crushing in the present invention, it further includes: screening with screens having apertures of 50 mm and 1 mm to obtain crushed stones of +50 mm, oversize materials of -50 to +1 mm, and coal of -1 mm; crushing the oversize materials of -50 to +1 mm and then screening with screens having apertures of 30 mm and 1 mm.

[0021] Preferably, before the primary crushing in the present invention, it further includes: feeding the coal gangue into a high-frequency vibrating screen or a relaxation screen with an aperture of 1 mm for screening to obtain coal of -1 mm, and subjecting the coal gangue of +1 mm to the above-mentioned crushing and screening treatment.

[0022] In the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue > 1.95, preferably, a counterattack crusher is adopted for primary crushing; an impact crusher is adopted for secondary crushing; a hammer crusher is adopted for tertiary crushing; a fine-grained hammer crusher is adopted for quaternary crushing. In a specific embodiment of the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue > 1.95, a counterattack crusher is adopted for primary crushing, and then screening is carried out with screens having apertures of 50 mm and 1 mm. The +50 mm materials are inspected. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones. Otherwise, they are subjected to secondary crushing together with the -50 to +1 mm materials, and the -1 mm materials are used as coal. Then screening is carried out with screens having apertures of 30 mm and 1 mm. The +30 mm materials are inspected. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones. Otherwise, they are subjected to tertiary crushing together with the -30 to +1 mm materials, and the -1 mm materials are used as coal. Then screening is carried out with screens having apertures of 15 mm and 1 mm. The +15 mm materials are inspected. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones. Otherwise, they are subjected to quaternary crushing together with the -15 to +1 mm materials, and the -1 mm materials are used as coal. Then screening is carried out with screens having apertures of 10 mm and 1 mm. The +10 mm materials are inspected. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones. Otherwise, they and the -10 to +1 mm materials continue to enter a fine-grained hammer crusher for fifth-stage crushing, and the -1 mm materials are used as coal. Then screening is carried out with screens having apertures of 5 mm and 2 mm. The +5 mm materials are inspected. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones. Otherwise, they and the -5 to +2 mm materials enter a fine-grained hammer crusher for continuous crushing, and then screening is carried out with a screen having an aperture of 2 mm. The -5 to +2 mm materials are inspected. When the ash content Ad ≥ 88 wt%, they are directly used as manufactured sand. Otherwise, they are crushed to -2 mm to be used as low-organic-matter soil. The -2 mm materials are used as medium- and high-organic-matter soil.

[0023] In a specific embodiment of the present invention, when the mass content ratio of SiO2 and Al2O3 in the coal gangue ash component > 1.95, a counterattack crusher is used for primary crushing, and then screening is carried out using sieves with apertures of 30 mm and 1 mm. The +30 mm material is obtained for inspection. When the ash content Ad of the material ≥ 88 wt%, it is directly used as crushed stone; otherwise, it is subjected to secondary crushing together with the -30~+1 mm material, and the -1 mm material is used as coal. Then screening is carried out using sieves with apertures of 15 mm and 1 mm. The +15 mm material is obtained for inspection. When the ash content Ad of the material ≥ 88 wt%, it is directly used as crushed stone; otherwise, it enters a hammer crusher together with the -15~+1 mm material for tertiary crushing, and the -1 mm material is used as coal. Then screening is carried out using sieves with apertures of 10 mm and 1 mm. The +10 mm material is obtained for inspection. When the ash content Ad of the material ≥ 88 wt%, it is directly used as crushed stone; otherwise, it is subjected to quaternary crushing together with the -10~+1 mm material, and the -1 mm material is used as coal. Then screening is carried out using sieves with apertures of 5 mm and 2 mm. The +5 mm material is obtained for inspection. When the ash content Ad of the material ≥ 88 wt%, it is directly used as crushed stone; otherwise, it enters a fine-grained hammer crusher together with the -5~+2 mm material for further crushing, and then screening is carried out using a sieve with an aperture of 2 mm. The -5~+2 mm material is inspected. When the ash content Ad ≥ 88 wt%, it is directly used as manufactured sand; otherwise, it is crushed to -2 mm to be used as low-organic matter soil; the -2 mm material is used as medium-high organic matter soil.

[0024] In the present invention, when the mass content ratio of SiO2 and Al2O3 in the coal gangue ash component is greater than 1.25 and less than or equal to 1.95, it is preferably subjected to primary crushing by a jaw crusher; secondary crushing by a hammer crusher; tertiary crushing by a cone crusher; and quaternary crushing by a fine-grained cone crusher. In a specific embodiment of the present invention, when the mass content ratio of SiO2 and Al2O3 in the coal gangue ash component is greater than 1.25 and less than or equal to 1.95, primary crushing is carried out by a jaw crusher, and then screening is carried out using sieves with apertures of 50 mm and 1 mm to obtain materials of +50 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones, otherwise they are subjected to secondary crushing together with the materials of -50~+1 mm; the materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 30 mm and 1 mm to obtain materials of +30 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones, otherwise they are subjected to tertiary crushing together with the materials of -30~+1 mm; the materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 15 mm and 1 mm to obtain materials of +15 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones, otherwise they enter a fine-grained cone crusher together with the materials of -15~+1 mm for quaternary crushing; then screening is carried out using sieves with apertures of 10 mm and 1 mm. The materials of -1 mm are used as coal, and the materials of +10 mm are inspected. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones, otherwise they and the materials of -10~+1 mm enter the fine-grained cone crusher again for fifth-stage crushing. The materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 5 mm and 2 mm to obtain materials of +5 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones, otherwise they are crushed together with the materials of -5~+2 mm, and then screening is carried out using a sieve with an aperture of 2 mm. The materials of -5~+2 mm are inspected. When their ash content Ad is ≥ 88 wt%, they are used as manufactured sand, otherwise they are further crushed to -2 mm to be used as low-organic matter soil; the materials of -2 mm are used as medium-high organic matter soil.

[0025] In a specific embodiment of the present invention, when the mass content ratio of SiO2 and Al2O3 in the coal gangue ash component is greater than 1.25 and less than or equal to 1.95, jaw crushers are used for primary crushing, and then screening is carried out using sieves with apertures of 30 mm and 1 mm. The +30 mm materials are obtained for inspection. When the ash content Ad of the materials is ≥88 wt%, they are directly used as crushed stones. Otherwise, they are crushed at the secondary level together with the -30~+1 mm materials, and the -1 mm materials are used as coal. Then screening is carried out using sieves with apertures of 15 mm and 1 mm. The +15 mm materials are obtained for inspection. When the ash content Ad of the materials is ≥88 wt%, they are directly used as crushed stones. Otherwise, they are crushed at the tertiary level together with the -15~+1 mm materials, and the -1 mm materials are used as coal. Then screening is carried out using sieves with apertures of 10 mm and 1 mm. The +10 mm materials are obtained for inspection. When the ash content Ad of the materials is ≥88 wt%, they are directly used as crushed stones. Otherwise, they are crushed at the quaternary level together with the -10~+1 mm materials, and the -1 mm materials are used as coal. Then screening is carried out using sieves with apertures of 5 mm and 2 mm. The +5 mm materials are obtained for inspection. When the ash content Ad of the materials is ≥88 wt%, they are directly used as crushed stones. Otherwise, they are crushed again together with the -5~+2 mm materials. Then screening is carried out using a sieve with an aperture of 2 mm. The -5~+2 mm materials are inspected. When their ash content Ad is ≥88 wt%, they are used as manufactured sand. Otherwise, they are further crushed to -2 mm to be used as low-organic-matter soil. The -2 mm materials are used as medium- and high-organic-matter soil.

[0026] In the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue ≤ 1.25 or the content of Al2O3 exceeds 37 wt%, it is preferred to adopt a jaw crusher for primary crushing; a pair-roll crusher for secondary crushing; a cone crusher for tertiary crushing, and a fine-grained cone crusher for quaternary crushing. In a specific embodiment of the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue ≤ 1.25 or the content of Al2O3 exceeds 37 wt%, a jaw crusher is adopted for primary crushing, and then screening is carried out using sieves with apertures of 50 mm and 1 mm to obtain materials of +50 mm for inspection. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones, otherwise they are subjected to secondary crushing together with the materials of -50~+1 mm, and the materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 30 mm and 1 mm to obtain materials of +30 mm for inspection. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones, otherwise they are subjected to tertiary crushing together with the materials of -30~+1 mm, and the materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 15 mm and 1 mm to obtain materials of +15 mm for inspection. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones, otherwise they enter a fine-grained cone crusher together with the materials of -15~+1 mm for quaternary crushing, and the materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 10 mm and 1 mm, and the materials of +10 mm are inspected. When their ash content Ad ≥ 88%, they are used as crushed stones, otherwise they continue to be subjected to fifth-stage crushing together with the materials of -10~+1 mm, and the materials of -1 mm are used as coal; then screening is carried out using sieves with apertures of 5 mm and 2 mm to obtain materials of +5 mm for inspection. When the ash content Ad of the materials ≥ 88 wt%, they are directly used as crushed stones, otherwise they are further crushed together with the materials of -5~+2 mm, and then screening is carried out using a sieve with an aperture of 2 mm. The materials of -5~+2 mm are inspected. When their ash content Ad ≥ 88%, they are used as manufactured sand, otherwise they are crushed to -0.5 mm together with the materials of -2 mm, and then flotation is carried out to recover coal and kaolin ore. Some intermediate products that are difficult to separate by flotation are used as medium-high organic matter soil.

[0027] In a specific embodiment of the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash composition of the coal gangue is ≤ 1.25 or the content of Al2O3 exceeds 37 wt%, jaw crushers are used for primary crushing, and then screening is carried out using sieves with apertures of 30 mm and 1 mm to obtain materials of +30 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones; otherwise, together with the materials of -30~+1 mm, roller crushers are used for secondary crushing, and the materials of -1 mm are used as coal. Then screening is carried out using sieves with apertures of 15 mm and 1 mm to obtain materials of +15 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones; otherwise, together with the materials of -15~1 mm, cone crushers are used for tertiary crushing, and the materials of -1 mm are used as coal. Then screening is carried out using sieves with apertures of 10 mm and 1 mm to obtain materials of +10 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones; otherwise, together with the materials of -10~+1 mm, quaternary crushing is carried out, and the materials of -1 mm are used as coal. Then screening is carried out using sieves with apertures of 5 mm and 2 mm to obtain materials of +5 mm for inspection. When the ash content Ad of the materials is ≥ 88 wt%, they are directly used as crushed stones; otherwise, together with the materials of -5~+2 mm, further crushing is carried out. Then screening is carried out using a sieve with an aperture of 2 mm, and the materials of -5~+2 mm are inspected. When their ash content Ad ≥ 88%, they are used as manufactured sand; otherwise, together with the materials of -2 mm, they are crushed to -0.5 mm, and then flotation is carried out to recover coal and kaolin ore, and some intermediate products that are difficult to separate by flotation are used as medium- and high-organic matter soil.

[0028] In the present invention, the sieves used for screening preferably include double-layer high-frequency vibrating screens or relaxation screens.

[0029] In the present invention, the coal of -1 mm is directly used as the fuel for the gangue power plant or used as the fuel for the gangue power plant after coal blending.

[0030] In the present invention, after the crushing and screening treatment, it preferably further includes: screening the crushed stones of different particle sizes using sieves with apertures of 30 mm, 15 mm, 10 mm, 5 mm, and 75 μm to remove low-strength fine powder, obtaining crushed stones of +30 mm, -30~+15 mm, -15~+10 mm, -10~+5 mm, manufactured sand of -5~+75 μm, and soil of -75 μm.

[0031] In the present invention, when the mass content ratio of SiO2 / Al2O3 in the ash component of the coal gangue is > 1.25, the separated soil of -5 to +2 mm is preferably obtained, and the separated soil of -5 to +2 mm is crushed to less than 2 mm to be used as low-organic-matter soil. In the present invention, the utilization method of the low-organic-matter soil preferably includes any one of (1) to (3): (1) measuring the plasticity index of the separated soil, when the plasticity index Ip > 7.5, it is used alone or as a whole to replace clay and is used as clay in the ingredients of building materials such as bricks and tiles and refractory materials; (2) measuring the particle size composition of the separated soil, when the particle size composition is close to that of natural soil, it is directly used as recycled soil for ecological restoration; (3) co-processing tailings and waste residues with relatively high potassium and phosphorus contents, then adding lime, limestone, and lime slag, calcining at 750 to 850 °C for 1 h at a constant temperature, and then cooling to room temperature to obtain active silicon fertilizer.

[0032] In the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash component of the coal gangue > 1.25, the obtained separated soil of -2 mm is preferably used as medium-high-organic-matter soil. In the present invention, the utilization method of the medium-high-organic-matter soil preferably includes any one of (1) to (3); (1) directly used as conditioning soil for sandy soil, saline-alkali soil, desert and gobi, and slightly polluted soil; (2) co-processing livestock and poultry manure, river and lake bottom mud, and easily degradable organic solid waste, and implementing medium-high temperature composting above 35 to 40 °C to prepare humus soil, and the easily degradable organic solid waste preferably includes one or more of fallen leaves, turf, and vegetable waste; (3) co-processing biomass raw materials, and implementing medium-high temperature fermentation above 35 °C to prepare humic acid fertilizer, and the biomass raw materials preferably include one or more of kitchen waste, livestock and poultry manure, municipal sludge, river and lake bottom mud, agricultural straw, and garden waste.

[0033] In the present invention, when the mass content ratio of SiO2 and Al2O3 in the ash component of the coal gangue ≤ 1.25 or the content of Al2O3 exceeds 37 wt%, the separated soil of -5 to +2 mm and the separated soil of -2 mm are preferably obtained, all crushed to -0.5 mm, and then flotation is carried out to recover coal and kaolin ore, and some intermediate products that are difficult to separate by flotation are used as medium-high-organic-matter soil.

[0034] In the present invention, the soil with CaO ≥ 5 wt% obtained by classifying and separating limestone-type coal gangue is preferably directly crushed to less than 3 mm, and co-processed with coal-based solid waste and high-alkali waste residue to activate and prepare cement-free cementitious materials. In the present invention, the coal-based solid waste preferably includes one or more of fly ash, desulfurized gypsum, and gasification ash slag; the high-alkali waste residue preferably includes one or more of magnesium slag, carbide slag, and red mud. In the present invention, the cement-free cementitious material is preferably used as a large-capacity CO2 absorption and solidification material for the absorption and mineralization of CO2.

[0035] Based on in-depth research on the composition and properties of coal gangue, especially based on in-depth research on parameters such as the mass content ratio of SiO2 / Al2O3 in the ash composition of coal gangue, different crushing and screening processes are then adopted to divide coal gangue into stone, soil, and coal, and they are respectively utilized reasonably and effectively. Coal is used as fuel in a gangue power plant, stone is prepared into machine-made sand and gravel as aggregate, part of the low-organic-matter soil is used as recycled soil to replace loess, part of the low-organic-matter soil replaces clay as raw materials for building materials and refractory materials, and part of the low-organic-matter soil is used to co-treat tailings and waste residues with relatively high potassium and phosphorus contents to prepare active silicon fertilizer; medium- and high-organic-matter soil is used to co-treat organic solid waste compost to prepare humus soil, and ferment to prepare humic acid fertilizer for ecological restoration and soil recovery; the high-CaO soil obtained by separation and sorting is used to co-prepare cement-free CO2 absorption and solidification materials with high-alkali industrial waste residues and coal-based solid wastes such as fly ash for CO2 absorption mineralization and secondary mineralization, truly achieving the full-component utilization of coal gangue by grading and separating its quality.

[0036] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments in 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 in the present invention without making creative efforts belong to the scope of protection of the present invention. Embodiment

[0037] For the washed coal gangue with an ash content of 81.5 wt% and a mass content ratio of SiO2 / Al2O3 in the ash composition equal to 2.02 in a certain mining area, after primary crushing with a counter - impact crusher, it enters a double - layer high - frequency vibrating screen (S1) with an upper - layer screen hole diameter of 50 mm and a lower - layer screen hole diameter of 1 mm for screening. The +50 mm material is obtained, and its ash content Ad is measured to be 89.19 wt%, which is directly used as crushed stone. The - 1 mm material is used as coal, and the - 50~+1 mm material enters an impact crusher for secondary crushing; then it enters a double - layer high - frequency vibrating screen with an upper - layer screen hole diameter of 30 mm and a lower - layer screen hole diameter of 1 mm for screening. The +30 mm material is obtained and inspected, and its ash content Ad is measured to be 89.02 wt%, which is directly used as crushed stone. The - 1 mm material is used as coal, and the - 30~+1 mm material enters a hammer - stone crusher for tertiary crushing; then it enters a double - layer high - frequency vibrating screen with an upper - layer screen hole diameter of 15 mm and a lower - layer screen hole diameter of 1 mm for screening. The +15 mm material is obtained, and its ash content Ad is measured to be 88.56 wt%, which is directly used as crushed stone. The - 1 mm material is used as coal, and the - 15~+1 mm material undergoes quaternary crushing; then it enters a double - layer high - frequency vibrating screen (S1) with an upper - layer screen hole diameter of 10 mm and a lower - layer screen hole diameter of 1 mm for screening. The +10 mm material is obtained, and its ash content Ad is measured to be 80.91 wt%. It is continuously crushed together with the - 10~+1 mm material, and then screened using screens with hole diameters of 5 mm and 2 mm. The +5 mm material is obtained, and its ash content is measured to be 88.38%, which is used as crushed stone; the - 5~+2 mm material has an ash content measured to be 85.35%. After further crushing, it is screened using a 2 - mm - diameter screen. The - 5~+2 mm material has an ash content measured to be 89.66%, which is used as manufactured sand, and the - 2 mm material is used as soil.

[0038] Through the above process, 10.53 wt% of coal, 21.74 wt% of crushed stone, 19.15 wt% of manufactured sand, and 47.58 wt% of soil are obtained, all of which are medium - to - high - organic - matter soil.

[0039] Based on the classification and quality separation obtained in Example 1, the crushed stone of different particle sizes is screened using screens with hole diameters of 30 mm, 15 mm, 10 mm, 5 mm, and 75 μm to remove fine powder with low strength, obtaining +30 mm, - 30~+15 mm, - 15~+10 mm, - 10~+5 mm crushed stone, as well as - 5~+75 μm manufactured sand and - 75 μm soil. The performance of the sand and gravel meets the index requirements of the National Standard of the People's Republic of China GB / T 14684 - 2022 "Sand for Construction". Example

[0040] For the washed coal gangue with an ash content of 73.89 wt% and a mass content ratio of SiO2 / Al2O3 in the ash composition equal to 1.58 in a certain mining area, a jaw crusher is used for primary crushing, and then it enters a double-deck high-frequency vibrating screen (S1) with an upper sieve hole diameter of 50 mm and a lower sieve hole diameter of 1 mm for screening. The +50 mm material is inspected, and its ash content Ad is measured to be 88.0 wt%, which is directly used as crushed stone. The -1 mm material is used as coal, and the -50~+1 mm material enters a hammer crusher for secondary crushing; then it enters a double-deck high-frequency vibrating screen (S1) with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 1 mm for screening. The +30 mm material is inspected, and its ash content Ad is measured to be 89.17 wt%, which is directly used as crushed stone. The -1 mm material is used as coal, and the -30~+1 mm material enters a cone crusher for tertiary crushing; then it enters a double-deck high-frequency vibrating screen (S1) with an upper sieve hole diameter of 15 mm and a lower sieve hole diameter of 1 mm for screening. The +15 mm material is obtained, and its ash content Ad is measured to be 85.66 wt%. It enters a fine-grained cone crusher together with the 15~+1 mm material for quaternary crushing. The -1 mm material is used as coal; then it enters a double-deck high-frequency vibrating screen (S1) with an upper sieve hole diameter of 10 mm and a lower sieve hole diameter of 1 mm for screening. The +10 mm material is inspected, and its ash content is measured to be 89.33%, which is used as crushed stone. The -1 mm material is used as coal; the -10~+1 mm material enters a fine-grained cone crusher for continuous crushing, and then enters a double-deck high-frequency vibrating screen with an upper sieve hole diameter of 5 mm and a lower sieve hole diameter of 2 mm for screening. The +5 mm material is obtained, and its ash content is measured to be 84.11%. Then it continues to be crushed together with the -5~+2 mm material, and then enters a high-frequency vibrating screen with a sieve hole diameter of 2 mm for screening. The -5~+2 mm material is obtained, and its ash content is measured to be 88.71%, which is used as machine-made sand. The -2 mm material is used as medium-high organic matter soil.

[0041] Through the above process, 14.23 wt% of coal, 16.47 wt% of crushed stone, 8.36 wt% of machine-made sand, and 60.94 wt% of soil are obtained, all of which are medium-high organic matter soil.

[0042] Based on the -1 mm coal obtained by classification and quality separation in Example 2, its ash content Ad is measured to be 42.78 wt%, and the sulfur content is 1.05 wt%. It is directly used as fuel for the gangue power plant.

[0043] Based on the partially separated soil obtained by grading and quality separation in Example 2, its particle size composition is close to that of natural soil and is used as recycled soil for ecological restoration. The partially separated soil is co-treated with 4.50 wt% of potassium tailings containing 4.90 wt% of K2O and 5.00 wt% of apatite tailings containing 8.44 wt% of P2O5, and further adding 6.05 wt% of limestone, calcined to 825 °C, kept at a constant temperature for 1 h and then cooled to room temperature to obtain active silicon fertilizer, which meets the index requirements of the Ministry of Agriculture's NY / T 797-2004 "Silicon Fertilizer" standard. Example

[0044] For the washed coal gangue with an ash content of 76.56 wt% and a mass content ratio of SiO2 / Al2O3 in the ash composition equal to 1.18 in a certain mining area, a jaw crusher is used for primary crushing, and then it enters a vibrating screen with an upper aperture of 30 mm and a relaxation screen (S2) with a lower aperture of 1 mm for screening. The +30 mm material is inspected, and its ash content Ad is measured to be 90.09 wt%, which is directly used as crushed stone. The -1 mm material is used as coal, and the -30~+1 mm material enters a pair-roll crusher for secondary crushing; then it enters a vibrating screen with an upper aperture of 15 mm and a relaxation screen (S2) with a lower aperture of 1 mm for screening. The +15 mm material is inspected, and its ash content Ad is measured to be 90.15 wt%, which is directly used as crushed stone. The -1 mm material is used as coal, and the -30~+1 mm material enters a fine-grained pair-roll crusher for tertiary crushing; then it enters a vibrating screen with an upper aperture of 10 mm and a relaxation screen (S2) with a lower aperture of 1 mm for screening. The +10 mm material is inspected, and its ash content Ad is measured to be 84.38%, and it enters a cone crusher together with the -10~+1 mm material for quaternary crushing. Then it enters a vibrating screen with an upper aperture of 5 mm and a relaxation screen (S2) with a lower aperture of 2 mm for screening. The +5 mm material is inspected, and its ash content Ad is measured to be 83.01 wt%, and it is crushed to -0.5 mm together with the -5~+2 mm and -2 mm materials, and then subjected to flotation separation to recover coal and kaolin ore. Some intermediate products that are difficult to be flotation-separated are used as medium and high organic matter soil.

[0045] Through the above process, 25.35 wt% of coal, 9.87 wt% of sand and gravel, 44.78% of kaolin ore and 20% of medium and high organic matter soil are obtained.

[0046] The medium- and high-organic matter soil obtained by hierarchical and quality separation based on Example 3 is directly used as the conditioning soil for sandy soil, saline-alkali soil, desert and gobi, and slightly polluted soil; part of the high-organic matter soil is co-treated with 12.5 wt% of food waste, 7 wt% of livestock manure, 10 wt% of municipal sludge, 5 wt% of river and lake bottom sludge, 25 wt% of agricultural straws and 15 wt% of garden waste, and humic acid fertilizer prepared by high-temperature fermentation at a temperature of 62.5 °C meets the industry standard of "Water-soluble Fertilizer Containing Humic Acid" (NY1106-2006) of the Ministry of Agriculture; part of the high-organic matter soil is co-treated with 5 wt% of chicken manure or pig and cow manure, 8.50 wt% of river and lake bottom sludge, and 12.5 wt% of fallen leaves, and then humus soil is prepared by aerobic composting at a temperature of 65 °C, and its performance is close to the performance index of the black soil in the Great Northern Wilderness.

[0047] The coal obtained by hierarchical and quality separation based on Example 3 has an ash content Ad of 41.78 wt% and a sulfur content of 0.79 wt%, and is directly used as the fuel for a gangue power plant; the recovered kaolin ore has a measured whiteness of 56.90, and part of the separated soil can be used instead of loess or clay. Example

[0048] For the washed coal gangue with an ash content of 66.45 wt% and a relatively high limestone content in a certain mining area, the CaO content in the ash composition is 17.38 wt%. After primary crushing with a counter - impact crusher, it enters a double - layer high - frequency vibrating screen (S1) with an upper - layer screen hole diameter of 50 mm and a lower - layer screen hole diameter of 1 mm for screening. The +50 mm material is obtained, and its ash content Ad is measured to be 88.21 wt%, which is directly used as crushed stone. The - 1 mm material is used as coal, and the - 50~+1 mm material enters an impact crusher for secondary crushing; then it enters a double - layer high - frequency vibrating screen with an upper - layer screen hole diameter of 30 mm and a lower - layer screen hole diameter of 1 mm for screening. The +30 mm material is obtained for inspection, and its ash content Ad is measured to be 89.03 wt%, which is directly used as crushed stone. The - 1 mm material is used as coal, and the - 30~+1 mm material enters a hammer crusher for tertiary crushing; then it enters a double - layer high - frequency vibrating screen with an upper - layer screen hole diameter of 15 mm and a lower - layer screen hole diameter of 1 mm for screening. The +15 mm material is obtained, and its ash content Ad is measured to be 88.62 wt%, which is directly used as crushed stone. The - 1 mm material is used as coal, and the - 15~+1 mm material undergoes quaternary crushing; then it enters a double - layer high - frequency vibrating screen (S1) with an upper - layer screen hole diameter of 10 mm and a lower - layer screen hole diameter of 1 mm for screening. The +10 mm material is obtained, and its ash content Ad is measured to be 81.27 wt%. It continues to be crushed together with the - 10~+1 mm material, and then enters a double - layer high - frequency vibrating screen with an upper - layer screen hole diameter of 5 mm and a lower - layer screen hole diameter of 2 mm for screening. The +5 mm material is obtained, and its ash content is measured to be 88.79%, which is used as high - CaO crushed stone. The - 5~+2 mm material is crushed to less than 3 mm and co - processed with 20 wt% of fly ash, 10 wt% of desulfurized gypsum, 15 wt% of gasification ash slag, and 30 wt% of magnesium slag to prepare a large - capacity CO2 - absorbing solid - free cementitious material. The - 2 mm material is used as medium - to - high - organic - matter soil.

[0049] Through the above process, 16.95 wt% of coal, 28.37 wt% of crushed stone, 23.66 wt% of - 3 mm high - CaO material, and 31.02 wt% of - 2 mm medium - to - high - organic - matter soil are obtained.

[0050] Based on the high - CaO - 3 mm material obtained by classification and separation in Example 4, it is co - processed with 20 wt% of fly ash, 10 wt% of desulfurized gypsum, 15 wt% of gasification ash slag, and 30 wt% of magnesium slag to prepare a large - capacity CO2 - absorbing solid - free cementitious material. The measured CO2 absorption rate is 0.118 g CO2 / g cementitious material.

[0051] 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 be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for the comprehensive utilization of all components of coal gangue by grading and separating according to quality, characterized in that, It includes the following steps: Crush and screen gangue with a mass content ratio of SiO2 to Al2O3 ≤ 1.25 to obtain crushed stones, manufactured sand, soil and coal of different particle sizes; The crushing and screening process includes: performing primary crushing on the gangue, screening with sieves having apertures of 30 mm and 1 mm to obtain crushed stones of +30 mm, oversize material No. 1 of -30~+1 mm and coal of -1 mm; performing secondary crushing on the oversize material No. 1, screening with sieves having apertures of 15 mm and 1 mm to obtain crushed stones of -30~+15 mm, oversize material No. 2 of -15~+1 mm and coal of -1 mm; performing tertiary crushing on the oversize material No. 2, screening with sieves having apertures of 10 mm and 1 mm to obtain crushed stones of -15~+10 mm, oversize material No. 3 of -10~+1 mm and coal of -1 mm; performing quaternary crushing on the oversize material No. 3 of -10~+1 mm, screening with sieves having apertures of 5 mm and 2 mm to obtain crushed stones of -10~+5 mm, manufactured sand of -5~+2 mm and soil of less than -2 mm; Use a jaw crusher for primary crushing, a pair-roll crusher for secondary crushing, a cone crusher for tertiary crushing, and a fine-grained cone crusher for quaternary crushing; Completely crush the obtained separated soil of -5~+2 mm and separated soil of -2 mm to -0.5 mm, then perform flotation to recover coal and kaolin ore, and use some intermediate products that are difficult to separate by flotation as medium and high organic matter soil.

2. The hierarchical and quality-separated full-component utilization method according to claim 1, characterized in that After the primary crushing, screen with sieves having apertures of 50 mm and 1 mm to obtain crushed stones of +50 mm, oversize material of -50~+1 mm and coal of -1 mm; crush the oversize material of -50~+1 mm and then screen with sieves having apertures of 30 mm and 1 mm.

3. The hierarchical and quality-fractionated full-component utilization method according to claim 1, characterized in that The sieves used for screening include double-deck high-frequency vibrating screens or relaxation screens.