Backfill paste CGIF material and carbon-negative filling mining method

Abstract

Disclosed in the present invention is a negative-carbon filling mining method with a backfill paste CGIF material, specifically comprising: crushing coal gangue into an aggregate having a particle size of 0-20 mm; mixing the crushed coal gangue with steel slag, fly ash, cement, and an alkali activator under stirring to prepare a filling paste; after coal mining, conveying the filling material to a goaf by means of a filling pipeline pre-laid in the goaf or a filling pipeline formed by drilling; and after the filling is completed, injecting carbon dioxide into the filling paste to form a CGIF material, and completing carbon dioxide adsorption and underground sequestration treatment. The method can realize large-scale utilization of gangue, and the prepared CGIF carbon sequestration paste has a low cost, a high carbon dioxide sequestration capacity, a further improved mechanical strength after carbon dioxide sequestration with CGIF, and a good supporting effect on an overlying rock stratum.

Description

A post-frame paste CGIF material and negative carbon filling mining method Technical Field

[0001] The invention relates to coal mining technology, in particular to a post-frame paste CGIF material negative carbon filling mining method. Background Art

[0002] Coal mining is often accompanied by problems such as roof collapse and ground subsidence. Backfill mining can effectively prevent these problems. For this reason, many mines in China use gangue backfill mining, which not only effectively controls ground pressure but also effectively solves the problem of how to exploit coal resources that are "underground, below ground, and below ground."

[0003] Furthermore, with the current focus on achieving carbon peak and carbon neutrality, strengthening the resource utilization of industrial and mining solid waste and the mineralization and storage of carbon dioxide are key approaches to achieving these dual carbon goals. However, existing carbon dioxide storage technologies generally suffer from low efficiency and high costs. Therefore, achieving effective adsorption and storage of carbon dioxide in goafs remains a major challenge. Summary of the Invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a negative carbon filling mining method for post-frame paste CGIF material, which can improve the utilization of waste rock, realize rock stratum control while performing filling mining, and realize the storage of carbon dioxide in the goaf.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a negative carbon filling mining method of a post-frame paste CGIF material, comprising the following steps:

[0007] S1. Crushing the coal gangue into aggregate with a particle size of 0-20 mm;

[0008] S2. Mixing the crushed coal gangue with steel slag, fly ash, cement, and alkali activator to prepare a filling paste;

[0009] S3. After coal mining, the filling material is transported to the goaf using the filling pipeline pre-laid in the goaf or the filling pipeline formed by drilling;

[0010] S4. After filling is completed, carbon dioxide is injected into the filling paste to form CGIF material, and carbon dioxide adsorption and downhole storage and disposal are completed.

[0011] Preferably, in step S1, the composition of the crushed coal gangue is that the content of 0-5 mm coal gangue accounts for 60-80% of the total amount, and the content of 5-20 mm coal gangue accounts for 20-40% of the total amount.

[0012] Preferably, in step S2, the ratio of the filling paste is: 60-85 parts of coal gangue aggregate, 5-10 parts of steel slag, 5-10 parts of fly ash, 0-5 parts of cement, and 0-5 parts of alkali activator, wherein the composition of the alkali activator is: 20-40 parts of sodium hydroxide, 30-70 parts of water glass, 0-5 parts of potassium sulfate, and 0-5 parts of sodium carbonate.

[0013] Preferably, in step S3, the filling pipeline arrangement is selected as a pre-laid method in the goaf or a filling pipeline formed by drilling holes on the ground.

[0014] Preferably, in step S3, CO2 is injected into the filling paste, and the injection amount is less than 1m 3 / s.

[0015] This embodiment also provides a CGIF material, which is prepared according to the above method.

[0016] The beneficial effects of the present invention are:

[0017] (1) Large-scale utilization of gangue is achieved, and the CGIF carbon sequestration paste prepared by the present invention is low-cost, economical, green and environmentally friendly;

[0018] (2) The CGIF material prepared by the present invention has high porosity and can significantly increase the ability to store carbon dioxide;

[0019] (3) Alkali activation is used to stimulate the activity of the cementitious material, so that the mechanical strength of CGIF is further improved after carbon dioxide is stored, and the supporting effect on the overlying rock layer is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] FIG1 is a schematic diagram of a negative carbon filling mining method for a post-frame paste CGIF material provided by an embodiment of the present invention.

[0022] Explanation of the accompanying symbols: 1-filling pipeline; 2-CO2 injection pipeline; 3-CO2 storage tank; 4-pressure gauge; 5-filling station. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1

[0025] The first step is to crush the coal gangue into aggregate with a particle size of 0-20mm, of which the 0-5mm coal gangue accounts for 60% of the total amount and the 5-20mm coal gangue accounts for 40% of the total amount; 80 parts of coal gangue, 10 parts of fly ash, 5 parts of cement, and 5 parts of gypsum are mixed and stirred to form a filling paste;

[0026] The second step is to use the filling pipeline pre-laid in the goaf to transport the filling material to the goaf to complete the filling;

[0027] The third step is to inject carbon dioxide into the filling paste with an injection volume of 0.5m 3 / s, completing the downhole storage and disposal of CO2 and forming CGIF material. A 10cm diameter CGIF material was taken to evaluate its mechanical properties and porosity.

[0028] Example 2

[0029] The first step is to crush the coal gangue into aggregate with a particle size of 0-20 mm, of which the 0-5 mm coal gangue accounts for 70% of the total amount and the 5-20 mm coal gangue accounts for 30% of the total amount; 80 parts of coal gangue, 5 parts of steel slag, 5 parts of fly ash, 5 parts of cement, and 5 parts of alkali activator (the alkali activator ratio is 20 parts of sodium hydroxide, 70 parts of water glass, 5 parts of potassium sulfate, and 5 parts of sodium carbonate) are mixed and stirred to form a filling paste;

[0030] The second step is to use the filling pipeline 1 pre-laid in the goaf to transport the filling material to the goaf, and to complete the filling in conjunction with the filling station 5, which is equipped with a pressure gauge 4;

[0031] The third step is to use the CO2 storage tank 3 and the CO2 injection pipeline 2 to inject carbon dioxide into the filling paste, with an injection volume of 0.5m 3 / s, completing the downhole storage and disposal of CO2 and forming CGIF material. A 10cm diameter CGIF material was taken to evaluate its mechanical properties.

[0032] Example 3

[0033] The first step is to crush the coal gangue into aggregate with a particle size of 0-20 mm, of which the 0-5 mm coal gangue accounts for 80% of the total amount and the 5-20 mm coal gangue accounts for 20% of the total amount; 75 parts of coal gangue, 10 parts of steel slag, 10 parts of fly ash, 2 parts of cement, and 3 parts of alkali activator (the alkali activator ratio is 30 parts of sodium hydroxide, 68 parts of water glass, 1 part of potassium sulfate, and 1 part of sodium carbonate) are mixed and stirred to form a filling paste;

[0034] The second step is to use the filling pipeline pre-laid in the goaf to transport the filling material to the goaf to complete the filling;

[0035] The third step is to inject carbon dioxide into the filling paste with an injection volume of 0.8m 3 / s, completing the downhole storage and disposal of CO2 and forming CGIF material. A 10cm diameter CGIF material was taken for evaluation of its mechanical properties.

[0036] Example 4

[0037] The first step is to crush the coal gangue into aggregate with a particle size of 0-20 mm, of which the 0-5 mm coal gangue accounts for 60% of the total amount and the 5-20 mm coal gangue accounts for 40% of the total amount; 70 parts of coal gangue, 10 parts of steel slag, 10 parts of fly ash, 5 parts of cement, and 5 parts of alkali activator (the alkali activator ratio is 40 parts of sodium hydroxide, 50 parts of water glass, 5 parts of potassium sulfate, and 5 parts of sodium carbonate) are mixed and stirred to form a filling paste;

[0038] The second step is to use the filling pipeline pre-laid in the goaf to transport the filling material to the goaf to complete the filling;

[0039] The third step is to inject carbon dioxide into the filling paste with an injection volume of 1.0m 3 / s, completing the downhole storage and disposal of CO2 and forming CGIF material. A 10cm diameter CGIF material was taken for evaluation of its mechanical properties.

[0040] Example 5

[0041] The first step is to crush the coal gangue into aggregate with a particle size of 0-20 mm, of which the 0-5 mm coal gangue accounts for 70% of the total amount and the 5-20 mm coal gangue accounts for 30% of the total amount; 75 parts of coal gangue, 8 parts of steel slag, 8 parts of fly ash, 2 parts of cement, and 2 parts of alkali activator (the alkali activator ratio is 30 parts of sodium hydroxide, 65 parts of water glass, 2 parts of potassium sulfate, and 3 parts of sodium carbonate) are mixed and stirred to form a filling paste;

[0042] The second step is to use the filling pipeline pre-laid in the goaf to transport the filling material to the goaf to complete the filling;

[0043] The third step is to inject carbon dioxide into the filling paste with an injection volume of 0.3m3 / s, completing the downhole storage and disposal of CO2 and forming CGIF material. A 10cm diameter CGIF material was taken for evaluation of its mechanical properties.

[0044] Example 6

[0045] The first step is to crush the coal gangue into aggregate with a particle size of 0-20 mm, of which the 0-5 mm coal gangue accounts for 80% of the total amount and the 5-20 mm coal gangue accounts for 20% of the total amount; 80 parts of coal gangue, 5 parts of steel slag, 5 parts of fly ash, 5 parts of cement, and 5 parts of alkali activator (the alkali activator ratio is 20 parts of sodium hydroxide, 70 parts of water glass, 5 parts of potassium sulfate, and 5 parts of sodium carbonate) are mixed and stirred to form a filling paste;

[0046] The second step is to use the filling pipeline pre-laid in the goaf to transport the filling material to the goaf to complete the filling;

[0047] The third step is to inject carbon dioxide into the filling paste with an injection volume of 1.0m 3 / s, completing the downhole storage and disposal of CO2 and forming CGIF material. A 10cm diameter CGIF material was taken for evaluation of its mechanical properties.

[0048] Table 1 CGIF material performance test results

[0049] The above results show that compared with Example 1, after treatment with carbon dioxide sequestration technology, the 3-day compressive strength and porosity of the CGIF materials in Examples 2-6 are significantly higher than those in Example 1, indicating that the carbon dioxide sequestration space potential of the CGIF materials of the present invention is large, and the negative carbon filling mining method of the post-frame paste CGIF material is feasible.

[0050] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A negative carbon filling mining method for post-frame paste CGIF material, characterized in that: The following steps are involved: S1. Crushing the coal gangue into aggregate with a particle size of 0-20 mm; S2. Mixing the crushed coal gangue with steel slag, fly ash, cement, and alkali activator to prepare a filling paste; S3. After coal mining, the filling material is transported to the goaf using the filling pipeline pre-laid in the goaf or the filling pipeline formed by drilling; S4. After filling is completed, carbon dioxide is injected into the filling paste to form CGIF material, and carbon dioxide adsorption and downhole storage and disposal are completed.

2. The negative carbon filling mining method of post-frame paste CGIF material according to claim 1, characterized in that: In step S1, the composition of the crushed coal gangue is that the content of 0-5 mm coal gangue accounts for 60-80% of the total amount, and the content of 5-20 mm coal gangue accounts for 20-40% of the total amount.

3. The negative carbon filling mining method of post-frame paste CGIF material according to claim 2, characterized in that: In step S2, the proportion of the filling paste is: 60-85 parts of coal gangue aggregate, 5-10 parts of steel slag, 5-10 parts of fly ash, 0-5 parts of cement, and 0-5 parts of alkali activator, wherein the composition of the alkali activator is: 20-40 parts of sodium hydroxide, 30-70 parts of water glass, 0-5 parts of potassium sulfate, and 0-5 parts of sodium carbonate.

4. The negative carbon filling mining method of post-frame paste CGIF material according to claim 1, characterized in that: In step S3, the filling pipeline layout mode is selected as a mode of pre-laying in the goaf or a filling pipeline formed by drilling holes on the ground.

5. The negative carbon filling mining method of post-frame paste CGIF material according to claim 3, characterized in that: In step S3, CO2 is injected into the filling paste, and the injection volume is less than 1m 3 / s.

6. A CGIF material, characterized in that: Prepared according to any one of claims 1 to 5.

Images