Gangue high-porosity material negative carbon filling mining method

Abstract

The invention discloses a negative carbon filling mining method for a gangue high-porosity material, and relates to the technical field of CO2 storage and filling mining, which comprises the following steps: spraying a rapid cementing material while blanking a gangue bulk material, forming a high-porosity filling body in a goaf, continuously injecting liquid CO2 into the closed high-porosity filling body through a pipeline, and filling the high-porosity filling body into a high-porosity filling body. The underground efficient sealing of CO2 is realized; the method is simple in design, the filling technology and CO2 storage are combined, efficient mining and filling are achieved, coal resource mining is not affected, the mine green mining and negative carbon filling construction process is promoted, a new concept of carbon storage is provided, wide application and research significance is achieved, and compared with a solid filling mining method, the method has the advantage that the method has a wide application prospect. And the gangue is fixed by using the rapid binding material to form a high-porosity material with bearing performance, so that the cost of a filling mining technology is reduced, and the original tamping process is simplified.

Description

Technical Field

[0001] The invention relates to the field of filling mining methods, and in particular to a negative carbon filling mining method for gangue high-porosity materials. Background Art

[0002] In 2020, the CO2 produced by the coal industry accounted for 70% to 80% of the total national emissions, about 7.605 billion tons. In order to achieve the strategic goal and reduce the overall CO2 emissions of coal, it is imperative to vigorously develop mine negative carbon filling technology. At present, the more mature method of storing CO2 is geological storage, but due to the high geological requirements of this method and the slow adsorption rate of the formation, the development of this technology is limited. In recent years, the development of green mining and filling technology in mines has been extremely rapid. It not only handles a large amount of solid waste such as gangue, fly ash, and slag, but also prevents large-scale migration of overburden and surface subsidence. At present, the main filling methods are costly, energy-intensive in raw material processing, and are also facing development difficulties. Therefore, it is proposed to combine filling mining with CO2 storage, and it is urgent to innovate a negative carbon filling mining method for gangue high-porosity materials. Summary of the invention

[0003] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a method for negative carbon filling and mining of high-porosity gangue materials. It addresses the problem of the scarcity of existing carbon fixation methods and utilizes negative carbon filling and mining of high-porosity gangue materials, thus opening up a new idea for underground CO2 storage.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for negative carbon filling mining of high-porosity gangue materials, wherein a fast-setting material is sprayed while the gangue bulk material is falling, a high-porosity filling body is formed in the goaf, and then liquid CO2 is continuously injected into the closed high-porosity filling body through a pipeline to achieve efficient CO2 underground storage. The specific steps include:

[0006] (1) Filling preparation stage: The filling station prepares the gangue and fast-setting materials crushed to the specified particle size, and arranges the CO2 delivery pipeline on the ground in advance; inspects and prepares the delivery equipment and pipelines to ensure efficient preparation and rapid delivery of materials;

[0007] (2) Filling and coal mining stage: While the working face is being mined, the crushed coal gangue is transported to the goaf by a multi-hole bottom-unloading conveyor hung on the top beam behind the hydraulic support. The multi-angle automatic grouting device set up behind the base of the hydraulic support sprays the fast-setting material synchronously with the gangue falling speed. The fast-setting material expands and solidifies rapidly to form a high-porosity filling body with load-bearing performance.

[0008] (3) Retaining wall laying stage: After the working face has advanced a certain distance, a high-strength concrete is sprayed by a shotcrete device to form a concrete retaining wall to seal the filled filling area I. After the sealing is completed, the same method is used to fill and seal the subsequent filling area II, and so on;

[0009] (4) CO2 storage stage: Liquid CO2 is transported to each closed filling area through the pre-buried transmission pipeline. Following the progress of filling and coal mining, CO2 is stored underground in each filling area in turn.

[0010] Preferably, the size of each filling area and the spacing between CO2 transport boreholes are determined by comprehensively considering the storage capacity, filling load requirements and diffusion range, and are integer multiples of the coal mining step distance.

[0011] Preferably, the concrete retaining wall is formed by spraying high-strength concrete onto the surface of the high-porosity filling body by a spraying device, and its strength meets the support requirements and CO2 sealing requirements and is not less than 10MPa.

[0012] Preferably, the arrangement of the liquid CO2 transmission pipeline includes ground vertical drilling, high-position special lane drilling, and adjacent surface grouting drilling.

[0013] Preferably, the spraying device for spraying fast-setting materials is a multi-angle automatic spraying device, which is set up behind the hydraulic support base. The spraying device can also be a filling device disclosed in a Chinese patent application with publication number CN117090629A, a high-efficiency filling device and method for high-porosity gangue materials.

[0014] Preferably, the rapid bonding material is a high-strength material generated by acid-base reaction and physical action of metal oxides and inorganic salts at room temperature. It will quickly solidify within a few minutes at room temperature, and the bonding strength between it and the solid waste material can reach 5MPa in 1 hour.

[0015] The beneficial effects of the present invention are:

[0016] The present invention mainly fills high-porosity materials into the goaf, and continuously introduces liquid CO2 after sealing to achieve the purpose of efficient CO2 storage underground. Compared with the solid filling mining method, this method uses fast-setting materials to fix the gangue to form a high-porosity material with load-bearing performance, which reduces the technical cost of filling mining and simplifies the original compaction process.

[0017] Liquid CO2 is transported to a closed filling area, and the hydration reaction fixes a certain amount of CO2. The high-porosity material of the filling body can also seal a large amount of CO2. This technology is safe, efficient, and feasible, which will help the coal mining industry to complete the new answer to the green development of the mining industry under the "dual carbon" goal. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0019] Figure 1 A cross-sectional diagram of negative carbon filling mining of high-porosity gangue materials provided by the present invention.

[0020] Figure 2 A plan view of negative carbon filling mining of high-porosity gangue materials provided by the present invention.

[0021] In the figure: 1-waste rock; 2-high-porosity filling body; 3-transport pipeline; 4-liquid CO2; 5-retaining wall; 6-multi-porous bottom discharge conveyor; 7-rapid cementing material; 8-multi-angle automatic spraying device; 9-hydraulic support; DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0023] A mining area uses the negative carbon filling mining method of high-porosity gangue materials to fill the goaf and store CO2. Figure 1 to Figure 2 As shown, this embodiment provides a method for negative carbon filling mining of high-porosity gangue materials, and the specific steps are as follows:

[0024] (1) According to the laboratory ratio, the particle size of gangue 1 is 40-50 mm, the porosity of high-porosity filling material is 30%, and the strength is about 80% of the dense filling, about 3.5 MPa, which basically meets the rock formation control requirements. The gangue is crushed to 40-50 mm on the ground and stored in the finished gangue bin.

[0025] (2) Vertical feeding drilling holes, rapid viscous material conveying drilling holes, and CO2 conveying drilling holes are arranged on the ground to the underground. The filling station equipment includes jaw crusher, vibrating screen, belt conveyor, mixer, CO2 condenser, pressure pump, etc.

[0026] (3) The finished gangue prepared on the ground is transported to the underground through the vertical feeding drilling hole, and then dropped to the rear of the hydraulic support 9 through the belt conveyor and the conveying device. The multi-angle automatic grouting device 8 set up behind the base of the hydraulic support sprays the fast-setting material 7 synchronously with the gangue dropping speed. The fast-setting material expands and condenses rapidly to form a high-porosity filling body 2 with bearing performance. The hydraulic support automatically moves with the progress of coal mining, and the dropping speed and grouting speed are regulated according to the coal mining speed. The multi-angle automatic grouting device 8 uses an existing grouting device, which is a prior art and will not be described in detail.

[0027] (4) According to theoretical analysis, the length of a carbon injection cycle is 200m, that is, after the working face advances 200m, a concrete retaining wall 5 is made by high-strength concrete spraying. After that, the liquid CO24 is delivered to the closed filling area through the borehole pump buried in advance on the ground and the delivery pipeline 3. Following the progress of filling coal mining, the CO2 underground storage is carried out in multiple closed filling areas (filling area I, filling area II, filling area III, etc.) of the working face. The recoverable reserves of this working face are 600,000 tons, and the fixed CO2 storage capacity is about 90,000 tons.

[0028] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for negative carbon filling mining of high-porosity gangue materials, characterized in that: While the loose gangue material is falling, the fast-setting material is sprayed to form a high-porosity filling body in the goaf. Then, liquid CO2 is continuously injected into the closed high-porosity filling body through the pipeline to achieve efficient CO2 storage underground. The specific steps include: (1) Filling preparation stage: The filling station prepares the gangue and fast-setting materials crushed to the specified particle size, and arranges the CO2 transmission pipeline on the ground in advance; (2) Filling coal mining stage: While the working face is being mined, the crushed coal gangue is transported to the goaf, and the rapid-setting material is sprayed synchronously with the gangue falling speed using a shotcrete device. The rapid-setting material expands and solidifies rapidly to form a high-porosity filling body with load-bearing performance; (3) Retaining wall laying stage: After the working face has advanced a certain distance, a high-strength concrete is sprayed by a shotcrete device to form a concrete retaining wall to seal the filled filling area I. After the sealing is completed, the same method is used to fill and seal the subsequent filling area II, and so on; (4) CO2 storage stage: Liquid CO2 is transported to each closed filling area through the pre-buried transmission pipeline. Following the progress of filling and coal mining, CO2 is stored underground in each filling area in turn.

2. A method for negative carbon filling mining of high-porosity gangue materials as claimed in claim 1, characterized in that: The size of each filling area and the spacing between CO2 transport boreholes are determined by comprehensively considering the storage capacity, filling load requirements and diffusion range, and are integer multiples of the coal mining step distance.

3. The method for negative carbon filling mining of high-porosity gangue materials according to claim 1, characterized in that: The concrete retaining wall is formed by spraying concrete onto the surface of the high-porosity filling body with a shotcrete device. Its strength meets the support requirements and CO2 sealing requirements and is not less than 10MPa.

4. The method for negative carbon filling mining of high-porosity gangue materials according to claim 1, characterized in that: The layout methods of liquid CO2 transmission pipeline include ground vertical drilling, high-position special tunnel drilling, and adjacent surface grouting drilling.

5. The method for negative carbon filling mining of high-porosity gangue materials according to claim 1, characterized in that: The spraying device for spraying fast-setting materials adopts a multi-angle automatic spraying device, which is set up behind the base of the hydraulic support.

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