Metal mine space carbon sequestration system and method based on upward filling of segmented stope

Abstract

The invention discloses a metal mine space carbon sequestration system and method based on upward filling of a segmented stope. A closed filling chamber is arranged in a staged blasting stope between a lower-stage filling body and an upper-stage unblasted ore body; an upper-stage drift roadway is arranged between the top of the closed filling chamber and the upper-stage unexploded ore body; a horizontal filling pipeline and a CO2 horizontal filling pipeline which are used for conveying the filling slurry and the CO2 gas to the closed filling chamber are arranged in the upper-stage access roadway, and the CO2 gas is mineralized to realize carbon sequestration through the filling slurry and the CO2 gas in the closed filling chamber. According to the method, the closed filling chamber is arranged in the goaf of the metal mine to seal and store the CO2 gas, the CO2 is utilized to be subjected to carbonization reaction with clinker minerals and hydration products in the filling cementing material, so that the dual purposes of'filling reinforcement 'and'filling carbon sequestration' are achieved, and environmental pollution cannot be generated in the whole CO2 gas sealing and storing process.

Description

Technical Field

[0001] This invention relates to the field of CO2 geological utilization and storage (CGUS) technology in metal mines, and particularly to a spatial carbon fixation system and method for metal mines based on upward filling in segmented stopes. Background Technology

[0002] Since the Industrial Revolution, the combustion of large amounts of fossil fuels has caused a dramatic surge in atmospheric CO2 concentrations, and the scale and rate of its emissions have severely disrupted the dynamic carbon balance throughout geological history. CO2 geological utilization and storage (CGUS) is a crucial technological means to reduce carbon emissions. However, in practical industrial scenarios, geological utilization, intended as a synergistic objective, dominates CGUS, resulting in limited increases in CO2 sequestration. CO2-EOR / EGR technology requires CO2 recycling, leading to low formation sequestration capacity. Deep saline aquifers, limited by complex heterogeneity and trapping conditions, have an actual effective sequestration rate of only 2%–3%, and well construction costs are high. Unmineable coal seams adsorb and store CO2 to displace CH4, resulting in low sequestration capacity. Relying solely on depleted oil and gas fields and deep saline aquifers to achieve climate goals presents a significant challenge in site selection for low-cost, large-scale sequestration, while also creating strategic opportunities for technological innovation and cross-sectoral collaboration.

[0003] Long-term, large-scale, and high-intensity mining of metallic mineral resources has created vast goaf areas within underground strata. As shallow deposits are depleted and deep mining progresses comprehensively, the resulting large-scale mining spaces are expected to become strategic sites for CO2 sequestration. Current research on CO2 sequestration in goaf areas primarily focuses on coal mines. CN119754770A, CN118774961A, CN113404538A, and CN113404538B all provide methods for CO2 sequestration in coal mine goaf areas. However, the poor coal and rock structure makes CO2 leakage easy, posing a fundamental challenge to long-term safe sequestration. Metal mines are mostly composed of crystalline igneous or metamorphic rocks, which, compared to coal mine surrounding rocks, possess significant physical and mechanical advantages due to their low permeability and high strength. CN 114961845 B provides a method for carbon sequestration in goaf areas based on layered approach tailings cemented backfilling mining. This method involves constructing and sealing strong (solid) and weak (virtual) backfill spaces in the goaf to sequestrate CO2 in a high-pressure gaseous or supercritical state. However, due to the relatively shallow mining area, this method still carries a serious risk of leakage. CN115653681 A provides a system and method for carbon dioxide sequestration in mineral resource goaf areas. This method involves injecting a CO2-air mixture and a mixture of biological enzymes and calcium-magnesium-containing solutions into the mineral resource goaf for reaction, thereby mineralizing CO2. This method ignores the requirements for backfill strength in the goaf and carries the risk of groundwater pollution. Therefore, developing or expanding safe CO2 sequestration methods in metal mining spaces is an important supplement to CGUS technology and the "low-carbon-zero-carbon-negative-carbon" green mining technology system for metal mines. Summary of the Invention

[0004] This invention discloses a spatial carbon fixation system and method for metal mines based on upward filling in segmented mining areas, in order to overcome the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A spatial carbon sequestration system for metal ores based on upward backfilling in segmented stopes, comprising: A sealed filling chamber is set up in the staged blasting stop between the next stage filling body and the previous stage unblasted ore body; the top of the sealed filling chamber is connected to the previous stage unblasted ore body by an upper stage access roadway. A horizontal filling pipe is installed in the upper stage approach roadway, and the horizontal filling pipe is connected to the filling flexible pipe; the filling flexible pipe extends into the sealed filling chamber, and the filling slurry enters the sealed filling chamber in sequence through the horizontal filling pipe and the filling flexible pipe. A CO2 horizontal filling pipeline is also installed in the upper-stage approach roadway; one end of the CO2 horizontal filling pipeline is connected to the ground CO2 storage tank; several bottom branch pipes connected to the CO2 horizontal filling pipeline are installed at the bottom of the CO2 horizontal filling pipeline; the bottom branch pipes are connected to one end of a high-pressure resistant flexible pipe through a gas supply regulating valve; the other end of the high-pressure resistant flexible pipe extends into the bottom of the sealed filling chamber, and a seepage prevention net is fixedly installed at the other end of the high-pressure resistant flexible pipe; CO2 gas enters the sealed filling chamber sequentially through the horizontal filling pipeline, the bottom branch pipes, the gas supply regulating valve, the high-pressure resistant flexible pipe, and the seepage prevention net.

[0006] Furthermore, the sealed filling chamber is formed by the low-permeability crystalline surrounding rock on both sides of the staged blasting mining area, the unblasted ore body in the middle stage, and the low-permeability reinforced concrete bottom slab, the seepage-proof filling retaining wall, and the low-permeability reinforced concrete top slab. The low-permeability reinforced concrete base plate is set at the bottom of the staged blasting stope, and the low-permeability reinforced concrete base plate and the bottom of the unblasted ore body in the middle stage form the middle stage access roadway. The low-permeability reinforced concrete roof slab is set on the top of the staged blasting mining area, and is fixed on both sides to the low-permeability crystalline surrounding rock and the top of the unblasted ore body in the middle stage, respectively. The seepage-proof and backfilling retaining wall is set between the unblasted ore body in the middle stage and the low-permeability reinforced concrete base slab, and the two ends of the seepage-proof and backfilling retaining wall are fixedly connected to the unblasted ore body in the middle stage and the low-permeability reinforced concrete base slab, respectively.

[0007] Furthermore, the low-permeability reinforced concrete roof slab is provided with CO2 pipe holes, filling pipe holes, observation windows, and exhaust / CO2 monitoring dual-purpose holes; a portable CO2 monitor is installed at the exhaust / CO2 monitoring dual-purpose holes; The filling flexible tube extends into the top of the sealed filling chamber through the filling pipe hole; The high-pressure resistant flexible pipe extends into the bottom of the sealed filling chamber through the CO2 pipe hole; The observation window is used to observe whether the filling slurry is in contact with the bottom of the low-permeability reinforced concrete roof after it enters the filling chamber through the flexible filling pipe from the horizontal filling pipe in the previous stage of the roadway. The exhaust / CO2 monitoring dual-purpose port is used to discharge CO2 gas from the sealed filling chamber after CO2 gas passes through the CO2 horizontal filling pipe in the upper stage approach roadway, through the bottom branch pipe and the high-pressure resistant flexible pipe, and enters the bottom of the sealed filling chamber. The portable CO2 monitor is used to monitor the gas discharged through the exhaust / CO2 monitoring dual-purpose port to help determine whether the CO2 gas fills the sealed filling chamber.

[0008] Furthermore, the seepage-proof and backfilled retaining wall is provided with pressure relief / drainage dual-purpose holes; a support structure is provided on the wall surface of the seepage-proof and backfilled retaining wall away from the low-permeability crystalline surrounding rock; The support structure includes thick steel plates for diagonal bracing, diagonal bracing, several horizontal channel steels at the top of the diagonal bracing, and several horizontal channel steels at the bottom of the diagonal bracing. The diagonal bracing is made of thick steel plates and is installed on the wall surface of the seepage-proof backfill retaining wall on the side away from the low-permeability crystalline surrounding rock. The horizontal channel steel at the top of the inclined brace is fixedly installed on the wall surface of the thick steel plate of the inclined brace away from the seepage prevention and filling retaining wall, and the center line of the horizontal channel steel at the top of the inclined brace is parallel to the low-permeability reinforced concrete base plate. The inclined bottom horizontal channel steel is set on the top of the low-permeability reinforced concrete base plate, and the inclined bottom horizontal channel steel is set inside the intermediate stage access roadway, with the center line of the inclined bottom horizontal channel steel parallel to the seepage prevention and filling retaining wall. The two ends of the diagonal brace are fixedly connected to the top horizontal channel steel and the bottom horizontal channel steel, respectively.

[0009] Furthermore, the CO2 horizontal filling pipeline is made of seamless steel pipe.

[0010] A carbon fixation method for a spatial carbon fixation system in a segmented stope with upward backfilling, comprising the following steps: S1: Blasting the intermediate ore body with blasting barrels to form a staged blasting stope, and high-pressure grouting to be carried out in the fracture zone and dissolution channel in the low-permeability crystalline surrounding rock to form a high-pressure grouting seal. S2: Lay a low-permeability reinforced concrete base slab at the bottom of the staged blasting mining area; S3: Construct a seepage-proof filling retaining wall and install a support structure in the intermediate-stage access roadway between the intermediate-stage unblasted ore body and the low-permeability reinforced concrete base slab. S4: A low-permeability reinforced concrete roof slab is installed between the low-permeability crystalline surrounding rock and the unblasted ore body in the middle stage; at this time, the installation of a closed filling chamber is completed, which is formed by the low-permeability crystalline surrounding rock such as igneous rock or metamorphic rock on both sides of the staged blasting mining area, the unblasted ore body in the middle stage, the low-permeability reinforced concrete bottom slab, the seepage prevention and filling retaining wall, and the low-permeability reinforced concrete roof slab. S5: A horizontal filling pipe and a CO2 horizontal filling pipe are installed in the upper-stage access roadway between the top of the sealed filling chamber and the unblasted ore body of the previous stage; and a flexible filling pipe connected to the horizontal filling pipe is extended into the top of the sealed filling chamber, and a high-pressure resistant flexible pipe is connected to the CO2 horizontal filling pipe and extended into the bottom of the sealed filling chamber. S6: Operate the ground filling station so that the filling slurry enters the filling chamber through the horizontal filling pipe in the previous stage access roadway and the filling flexible pipe; until the filling slurry contacts the bottom of the low-permeability reinforced concrete roof slab. S7: CO2 gas is introduced through the CO2 horizontal filling pipeline in the previous stage roadway, through the bottom branch pipe and the high-pressure resistant flexible pipe, into the bottom of the sealed filling chamber until the CO2 gas reaches the target filling volume, thus completing the solidification and sealing of the CO2 gas.

[0011] Beneficial Effects: The present invention discloses a spatial carbon fixation system and method for metal mines based on upward backfilling in segmented stopes. This system involves setting up a sealed backfill chamber within a segmented blasted stope between the lower-stage backfill and the upper-stage unblasted ore body. An upper-stage access roadway is provided between the top of the sealed backfill chamber and the upper-stage unblasted ore body. A horizontal backfilling pipe and a horizontal CO2 injection pipe are installed within the upper-stage access roadway to transport backfill slurry and CO2 gas to the sealed backfill chamber. Carbon fixation is achieved by mineralizing CO2 gas within the sealed backfill chamber using the backfill slurry and CO2 gas. This invention uses a sealed filling chamber set up in the goaf of a staged blasting stope in a metal mine to seal CO2 gas, which solves the problem of CO2 leakage that is common in traditional methods of sealing CO2 in coal mine goafs. It utilizes the carbonization reaction between CO2 and the clinker minerals and hydration products in the filling cementitious material to achieve the dual purpose of "filling enhancement" and "filling carbon fixation", and the entire CO2 gas sealing process does not produce environmental pollution. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the overall spatial carbon sequestration method for metal mines based on high-concentration cemented backfilling in segmented stopes, according to the present invention. Figure 2 This is a partial schematic diagram of the seepage-proof backfill retaining wall according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the effect formed when the filling material reaches the designed strength in an embodiment of the present invention.

[0014] In the diagram: 1. Low-permeability crystalline surrounding rock; 2. Dissolution channel; 3. Fault zone; 4. High-pressure grouting sealing; 5. Lower stage filling body; 6. Intermediate stage access roadway; 7. Intermediate stage unblasted ore body; 8. Upper stage access roadway; 9. Upper stage unblasted ore body; 10. Blasting barrel; 11. Intermediate stage filling body; 12. Low-permeability reinforced concrete base slab; 13. Anti-seepage filling retaining wall; 14. Pressure relief / drainage dual-purpose hole; 15. Thick steel plate for diagonal bracing; 16. Diagonal bracing; 17. Horizontal channel steel at the top of the diagonal bracing; 18. Horizontal channel steel at the bottom of the diagonal bracing; 19. Low-permeability reinforced concrete roof slab; 20. CO2 pipe hole; 21. 21. Filling pipe hole; 22. Observation window; 23. Sealing gasket; 24. Exhaust / CO2 monitoring dual-purpose hole; 25. Threaded sleeve; 26. Exhaust valve; 27. Horizontal filling pipe; 28. Filling flexible pipe; 29. ​​Flange; 30. Sealing gasket; 31. CO2 horizontal filling pipe; 32. Pipe bottom branch; 33. Gas supply regulating valve; 34. High-pressure resistant flexible pipe; 35. Gas leakage prevention mesh; 36. CO2 gas; 37. Pluged CO2 pipe hole; 38. Pluged filling pipe hole; 39. Pluged exhaust / CO2 monitoring dual-purpose hole; 40. Portable CO2 monitor. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] This embodiment introduces a spatial carbon fixation system and method for metal ores based on upward filling in segmented stopes, such as... Figure 1-3 As shown, it includes: A sealed filling chamber is set up in the goaf of the staged blasting stope between the next stage filling body 5 and the previous stage unblasted ore body 9; an upper stage access roadway 8 is set up between the top of the sealed filling chamber and the previous stage unblasted ore body 9. A horizontal filling pipe 27 is installed in the upper stage approach roadway 8, and the horizontal filling pipe 27 is connected to the filling flexible pipe 28; the filling flexible pipe 28 extends into the sealed filling chamber; the filling slurry enters the sealed filling chamber in sequence through the horizontal filling pipe 27 and the filling flexible pipe 28. A CO2 horizontal filling pipeline 31 is also installed in the upper-stage access roadway 8; one end of the CO2 horizontal filling pipeline 31 is connected to the ground CO2 storage tank; several bottom branch pipes 32 connected to the bottom of the CO2 horizontal filling pipeline 31 are installed; the bottom branch pipes 32 are connected to one end of a high-pressure resistant flexible pipe 34 through a gas supply regulating valve 33; the other end of the high-pressure resistant flexible pipe 34 extends into the bottom of the sealed filling chamber, and a gas seepage prevention net 35 is fixedly installed at the other end of the high-pressure resistant flexible pipe 34; CO2 enters the sealed filling chamber sequentially through the horizontal filling pipeline 31, the bottom branch pipe 32, the gas supply regulating valve 33, the high-pressure resistant flexible pipe 34, and the gas seepage prevention net 35. Preferably, the sealed filling chamber is formed by the low-permeability crystalline surrounding rocks such as igneous rocks or metamorphic rocks on both sides of the goaf of the staged blasting mining area, the unblasted ore body in the middle stage, and the low-permeability reinforced concrete bottom slab 12, the seepage prevention filling retaining wall 13, and the low-permeability reinforced concrete top slab 19. The low-permeability reinforced concrete base plate 12 is set at the bottom of the staged blasting mining area; and the low-permeability reinforced concrete base plate 12 and the bottom of the unblasted ore body 7 in the middle stage form the middle stage access roadway 6. The low-permeability reinforced concrete roof slab 19 is disposed between the low-permeability crystalline surrounding rock 1 and the intermediate-stage unblasted ore body 7, and the two sides of the low-permeability reinforced concrete roof slab 19 are fixedly connected to the side wall surface of the low-permeability crystalline surrounding rock 1 and the top of the side wall surface of the intermediate-stage unblasted ore body 7, respectively. The seepage-proof filling retaining wall 13 is disposed between the unblasted ore body 7 in the middle stage and the low-permeability reinforced concrete base slab 12, and the two ends of the seepage-proof filling retaining wall 13 are fixedly connected to the unblasted ore body 7 in the middle stage and the low-permeability reinforced concrete base slab 12, respectively.

[0017] Specifically, such as Figure 1 As shown, this embodiment is based on the high-concentration cemented backfill mining technology in subgrade mining of metal mines, and involves the sealing modification of an open stope. The high-concentration cemented backfill mining method in subgrade stopes is mainly used for the efficient mining of steeply dipping, thick ore bodies. First, the ore body is divided into different stages according to different heights, and then each stage is further divided into a first-stage stope and a second-stage stope. Roadways are excavated in each stope, and then the ore is mined in stages. First, the first-stage stope is mined and backfilled, with blasting barrels 10 inserted into the ore body. The second-stage stope is left as a pillar. Then, the second-stage stope is mined and backfilled, using the stable backfill material from the first-stage stope as a sidewall. This alternating upward mining and backfilling continues until the ore body is exhausted.

[0018] In this example, a new CO2 horizontal filling pipeline 31 is installed to connect to a newly built CO2 storage tank on the ground. Several branch pipes are set at the bottom of the CO2 horizontal filling pipeline 31. A gas supply regulating valve 33 is installed on the bottom branch pipe 32. The other end of the gas supply regulating valve 33 is connected to a high-pressure resistant flexible pipe 34. A seepage prevention and solidification net 35 is installed at the far end of the high-pressure resistant flexible pipe 34, extending all the way to the bottom of the sealed filling chamber. The filling slurry is filled into the sealed filling chamber through the horizontal filling pipeline 27 in the upper stage access roadway 8 via the filling flexible pipe 28. Based on the carbonization and oxidation principle, the filling slurry and CO2 gas 36 are filled into the sealed filling chamber through the CO2 horizontal filling pipeline 31 and the horizontal filling pipeline 27, respectively. The CO2 reacts with the clinker minerals and hydration products in the cementitious material of the intermediate stage filling body 11 formed by the filling slurry to achieve the dual purpose of "filling strengthening" and "filling carbon fixation".

[0019] Preferably, the low-permeability reinforced concrete roof slab 19 is provided with a CO2 pipe hole 20, a filling pipe hole 21, an observation window 22, and a dual-purpose exhaust / CO2 monitoring hole 24; a portable CO2 monitor 40 is installed at the dual-purpose exhaust / CO2 monitoring hole 24; The filling flexible tube 28 extends into the sealed filling chamber through the filling pipe hole 21; The high-pressure resistant flexible tube 34 extends into the bottom of the sealed filling chamber through the CO2 pipe hole 20; The observation window 22 is used to observe whether the filling slurry is in contact with the bottom of the low-permeability reinforced concrete roof slab after the filling slurry enters the filling chamber through the filling flexible pipe 28 via the horizontal filling pipe 27 in the previous stage access roadway 8, and to observe the water seepage of the filling body and the flow of the filling slurry; the exhaust / CO2 monitoring dual-purpose hole 24 is used to discharge the residual gas in the closed filling chamber after CO2 gas enters the bottom of the closed filling chamber through the CO2 horizontal filling pipe 31 in the previous stage access roadway 8 via the bottom branch pipe 32 and the high-pressure resistant flexible pipe 34. The portable CO2 monitor 40 is used to monitor the gas discharged through the exhaust / CO2 monitoring dual-purpose port 24 to help determine whether the CO2 gas fills the sealed filling chamber.

[0020] Specifically, using engineering techniques, a new low-permeability reinforced concrete roof slab 19 is constructed above the filling trench using sealing materials. The roof slab has pre-drilled holes for CO2 pipes 20, filling pipes 21, observation windows 22, and a dual-purpose venting / CO2 monitoring hole 24. Together with the low-permeability crystalline surrounding rock 1, the unblasted ore body 7 of the intermediate stage, the low-permeability reinforced concrete base slab 12, the seepage-proof filling retaining wall 13, and the low-permeability reinforced concrete roof slab 19, it forms a sealed filling chamber. A threaded sleeve 25 is installed inside the CO2 venting / monitoring dual-purpose hole 24, and an venting valve 26 is installed on the hole.

[0021] Preferably, the seepage-proof filling retaining wall 13 is provided with a pressure relief / drainage dual-purpose hole 14; a support structure is provided on the wall surface of the seepage-proof filling retaining wall 13 on the side away from the low-permeability crystalline surrounding rock 1; The support structure includes thick steel plates 15 for diagonal bracing, diagonal bracing 16, several horizontal channel steels 17 at the top of the diagonal bracing, and several horizontal channel steels 18 at the bottom of the diagonal bracing. The diagonal bracing is made of thick steel plate 15 and is installed on the wall surface of the seepage-proof filling retaining wall 13 on the side away from the low-permeability crystalline surrounding rock 1. The horizontal channel steel 17 of the top of the inclined brace is fixedly installed on the wall surface of the thick steel plate 15 of the inclined brace away from the seepage prevention and filling retaining wall 13, and the center line of the horizontal channel steel 17 of the top of the inclined brace is parallel to the low-permeability reinforced concrete base plate 12. The inclined bottom horizontal channel steel 18 is set on the top of the low-permeability reinforced concrete base plate 12, and the inclined bottom horizontal channel steel 18 is set inside the intermediate stage access roadway 6. The center line of the inclined bottom horizontal channel steel 18 is parallel to the seepage prevention and filling retaining wall 13. The two ends of the rigid structure diagonal brace 16 are fixedly connected to the top horizontal channel steel 17 and the bottom horizontal channel steel 18 of the diagonal brace, respectively.

[0022] Specifically, such as Figure 3 As shown, at the junction of the bottom of the unblasted ore body 7 and the access roadway 6 in the intermediate stage, a seepage-proof filling retaining wall 13 is constructed between the low-permeability reinforced concrete base slab 12 and the unblasted ore body 7 in the intermediate stage. The wall is equipped with drainage / pressure relief holes 14. A support structure is added in front of the seepage-proof filling retaining wall 13. The support structure includes thick steel plates 15 with the same cross-section as the wall surface for diagonal bracing. Several rows of horizontal channel steel 17 at different heights are welded to the surface of the thick steel plates 15 for diagonal bracing. Several rows of horizontal channel steel 18 at the bottom of the low-permeability reinforced concrete base slab at the feet of the steel structure diagonal bracing 16 are also added. The horizontal channel steel 18 at the bottom of the diagonal bracing is bolted to the low-permeability reinforced concrete base slab 12. The structure of the seepage-proof filling retaining wall system with diagonal bracing is determined based on the maximum horizontal stress formed during the filling process.

[0023] Specifically, the horizontal filling pipe 27 in the previous stage approach roadway 8 is segmented according to the span of the sealed filling chamber. The ends of the front and rear sections are connected by flanges 29 and bolts, and the flanges 29 are sealed with gaskets 30 for airtightness. The end of the horizontal filling pipe 27 in the roadway is connected to the flexible filling pipe 28. The other end of the flexible filling pipe 28 extends into the top of the sealed filling chamber through a pre-reserved filling pipe hole 21 in the low-permeability reinforced concrete roof slab 19. After the flexible filling pipe 28 passes through, the area around the filling pipe hole 21 is sealed.

[0024] Preferably, in this embodiment, the CO2 horizontal filling pipe 31 is made of seamless steel pipe and is segmented according to the span of the sealed filling chamber. The ends of the front and rear sections are connected by flanges 29 and bolts, and the flanges 29 are sealed with gaskets 30 for airtightness. Several branch pipes extend from the bottom of the CO2 horizontal filling pipe 31. A gas supply regulating valve 33 is installed on the bottom branch pipe 32. The other end of the gas supply regulating valve is connected to a high-pressure resistant flexible pipe 34 for CO2 transportation. The other end of the high-pressure resistant flexible pipe 34 extends into the bottom of the sealed filling chamber through a reserved CO2 pipeline hole 20. After the CO2 transportation high-pressure resistant flexible pipe 34 passes through, the reserved CO2 pipeline hole 20 is sealed around it. An air-permeable anti-slurry net 35 is installed at the far end of the CO2 transportation high-pressure resistant flexible pipe 34 to prevent slurry backflow.

[0025] This example also discloses a carbon fixation method for a metal ore spatial carbon fixation system based on upward filling of a segmented stope, comprising the following steps: S1: Use blasting barrel 10 to blast the middle stage ore body to form a stage blasting stope, and perform high pressure grouting in the fracture zone 3 and dissolution channel 2 in the low permeability crystalline surrounding rock 1 to form high pressure grouting sealing 4. Specifically, since the low-permeability crystalline surrounding rock 1 cannot contain escape channels for CO2, high-pressure grouting should be carried out in advance for the fault zone 3 caused by tectonic movement and the dissolution channel 2 formed by groundwater erosion to form a high-pressure grouting seal 4. The blasting range of the mining area is determined based on factors such as safety, progress, cost, scheduling, and the design span of the sealed filling chamber, and blasting is carried out through the blasting tube 10. The ore formed by the blasting is used to fill the intermediate stage access roadway 6. After all the ore is removed by the ore card, high-pressure grouting is carried out on the dissolution channel 2 and fault zone 3 existing in the low-permeability crystalline surrounding rock 1 using engineering methods to form a high-pressure grouting seal 4.

[0026] S2: Lay a low-permeability reinforced concrete base slab 12 at the bottom of the staged blasting mining area; Specifically, since this embodiment is based on carbon fixation in an upward-filled metal ore space, when the constructed sealed filling chamber is not the lowest level filling chamber, the low-permeability, high-reinforcement concrete base slab comes from the top slab of the next stage filling chamber.

[0027] S3: Construct a seepage-proof and filling retaining wall 13 between the unblasted ore body 7 and the low-permeability reinforced concrete base slab 12, and install a support structure in the intermediate-stage access roadway 6 on the side of the seepage-proof and filling retaining wall 13 away from the low-permeability crystalline surrounding rock 1. Specifically, the seepage-proof backfill retaining wall 13 is constructed after the ore in the mining area is removed. The construction location is inside the intermediate stage access roadway 6, between the intermediate stage unblasted ore body 7 and the low-permeability reinforced concrete base slab 12. The wall body is provided with drainage / pressure relief holes 14 to release the initial pressure of backfilling in a timely manner and to observe the performance of the slurry field. It can also be used for drainage when necessary.

[0028] S4: A low-permeability reinforced concrete roof slab 19 is installed between the low-permeability crystalline surrounding rock 1 and the intermediate-stage unblasted ore body 7; at this time, the installation of a closed filling chamber is completed, which is formed by the low-permeability crystalline surrounding rock 1 (such as igneous rock or metamorphic rock) on both sides of the goaf of the staged blasting stope, the intermediate-stage unblasted ore body 7, the low-permeability reinforced concrete bottom slab 12, the seepage prevention and filling retaining wall 13, and the low-permeability reinforced concrete roof slab 19. Specifically, in order to balance the blasting range of the primary mining area and the construction scale of the sealed filling chamber, the blasting range of the primary mining area and the construction span of the sealed filling chamber should be determined based on factors such as safety, progress, cost, and scheduling. The structural parameters of the low-permeability reinforced concrete roof slab 19 should be determined based on factors such as the span of the sealed filling chamber and the expansion pressure it bears.

[0029] S5: A horizontal filling pipe 27 and a CO2 horizontal filling pipe 31 are installed in the upper-stage access roadway 8 between the top of the sealed filling chamber and the unblasted ore body 9 of the previous stage; and a filling flexible pipe 28 connected to the horizontal filling pipe 27 is extended into the sealed filling chamber through the filling pipe hole 21, and a high-pressure resistant flexible pipe 34 is connected to the CO2 horizontal filling pipe 31 and extended into the bottom of the sealed filling chamber through the CO2 pipe hole 20. S6: Operate the ground filling station so that the filling slurry enters the filling chamber through the filling flexible pipe 28 via the horizontal filling pipe 27 in the previous stage access roadway 8; until the filling slurry contacts the bottom of the low-permeability reinforced concrete roof slab.

[0030] Specifically, after the sealed filling chamber is constructed, the ground filling station is operated. The filling slurry enters the filling chamber through the horizontal filling pipe 27 in the previous stage access roadway 8 and then through the filling flexible pipe 28. The drainage / pressure relief dual-purpose hole 14 is opened to prevent possible pressure concentration and drainage issues. The observation window 22 is opened to observe the slurry condition in the sealed filling chamber. Filling is stopped when the slurry contacts the bottom of the low-permeability reinforced concrete roof slab. The observation window 22 is then closed and sealed with a sealing gasket 23.

[0031] Specifically, the function of the drainage / pressure relief hole 14 is to drain water. Since this embodiment uses high-concentration cementitious filling, the main function of the drainage / pressure relief hole 14 in this embodiment is to dynamically adjust the slurry concentration.

[0032] Specifically, after the filling slurry is completely filled, the flexible filling pipe 28 is pulled out from the closed filling chamber and disconnected from the horizontal filling pipe 27 in the roadway. The horizontal filling pipe 27 is also disconnected from the previous horizontal filling pipe at the flange 29. After clearing the blockage, it is taken to other mining areas for use, and the reserved filling pipe hole 21 in the roof is sealed.

[0033] S7: CO2 is introduced through the CO2 horizontal filling pipe 31 in the previous stage approach roadway 8, through the bottom branch pipe 32 and the high-pressure resistant flexible pipe 34, into the bottom of the sealed filling chamber until the CO2 gas reaches the target filling amount, so as to complete the solidification and sealing of the CO2 gas.

[0034] Specifically, in this embodiment, the amount of CO2 gas injected is calculated based on the composition of the filling cementitious material. The amount of CO2 gas injected should ensure that as much CO2 gas as possible is mineralized while maintaining the cementitious properties of the cementitious material and the strength of the intermediate stage filling body 11.

[0035] Specifically, during CO2 gas filling, first, the drainage / pressure relief dual-purpose hole 14 on the seepage-proof filling retaining wall 13 is sealed. Then, the exhaust valve 26 on the exhaust / CO2 monitoring dual-purpose hole 24 on the low-permeability reinforced concrete roof slab is fully opened. The gas supply regulating valve 33 on the bottom branch pipe 32 is adjusted to inject CO2 into the filling body at appropriate pressure and flow rate. Under the action of filling pressure and buoyancy, CO2 diffuses upwards and outwards from the bottom. Residual air in the sealed filling chamber is discharged outdoors through the exhaust / CO2 monitoring dual-purpose hole 24. The portable CO2 monitor 40 probe is placed near the exhaust / CO2 monitoring dual-purpose hole 26. When a high concentration of CO2 is detected and the target filling volume is reached, the exhaust valve 26 is tightened.

[0036] Specifically, after the CO2 gas reaches the target filling volume, the high-pressure resistant flexible pipe 34 in the previous stage approach roadway 8 is sealed using tools such as pipe wrenches, and gas is injected into the horizontal filling pipe 31 in the negative pressure roadway. Then, the gas supply regulating valve 33 is closed, and the high-pressure resistant flexible pipe 34 is cut off and sealed. This section of the CO2 horizontal filling pipe above the filling chamber is disconnected from the previous section and taken to other mining areas for future use.

[0037] Specifically, once the filling material reaches its design strength, the thick steel plate 15, steel structure diagonal brace 16, and bottom transverse channel steel 18 of the diagonal brace are disassembled and relocated to other places for future use. The final effect is as follows: Figure 3 As shown.

[0038] Specifically, after the intermediate stage ore body is fully filled and mined, the upper stage ore body will be mined upwards. At this time, the low-permeability reinforced concrete roof slab 19 of the intermediate stage closed filling chamber will be transformed into the low-permeability reinforced concrete floor slab 12 of the upper stage closed filling chamber. Figure 3 The sealed CO2 pipeline hole 37, the sealed filling pipeline hole 38, and the sealed exhaust / CO2 monitoring dual-purpose hole 39 are respectively the CO2 pipeline hole 20, the filling pipeline hole 21, and the exhaust / CO2 monitoring dual-purpose hole 24, which are sealed after the original CO2 gas filling is completed when the upper stage of the ore body is started to be mined upwards.

[0039] Specifically, in this embodiment, when filling with CO2 gas, the filling slurry should be made fluid so that the channels and air cavities formed by CO2 gas seepage can self-heal. Since the filling body is connected to the low-permeability reinforced concrete top slab 19, no air cushion layer will appear at the bottom of the low-permeability reinforced concrete top slab 19. Even if an air cushion layer appears, its pressure will gradually dissipate as the CO2 gas mineralizes.

[0040] This embodiment has the following beneficial effects: 1. This embodiment takes into account both the economic benefits of backfill mining in metal mines and the environmental benefits, which is an important breakthrough in the field of CO2 utilization and storage.

[0041] 2. This embodiment is based on the principle of carbonization curing. It utilizes CO2 to react with the clinker minerals and hydration products in the filling cementitious material to achieve the dual purpose of "filling strengthening" and "filling carbon fixation".

[0042] 3. This embodiment is based on existing mature technology and takes into account the purpose of CO2 storage. It involves engineering modifications to the mining site. The overall principle of the method is simple but feasible and highly operable.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spatial carbon fixation system for metal ores based on upward filling in segmented stopes, characterized in that, include: A sealed filling chamber is set up in the stage blasting stop between the next stage filling body (5) and the previous stage unblasted ore body (9); An upper-stage access roadway (8) is provided between the top of the sealed filling chamber and the upper-stage unblasted ore body (9). A horizontal filling pipe (27) is provided in the upper stage approach roadway (8), and the horizontal filling pipe (27) is connected to the filling flexible pipe (28); the filling flexible pipe (28) extends into the closed filling chamber, and the filling slurry enters the closed filling chamber in sequence through the horizontal filling pipe (27) and the filling flexible pipe (28); A CO2 horizontal filling pipeline (31) is also installed in the upper stage access roadway (8); one end of the CO2 horizontal filling pipeline (31) is connected to the ground CO2 storage tank; several bottom branch pipes (32) connected to the CO2 horizontal filling pipeline (31) are installed at the bottom of the CO2 horizontal filling pipeline (31); the bottom branch pipe (32) is connected to one end of the high-pressure resistant flexible pipe (34) through the gas supply regulating valve (33); the other end of the high-pressure resistant flexible pipe (34) extends into the bottom of the sealed filling chamber, and the end of the other end of the high-pressure resistant flexible pipe (34) is fixedly provided with a gas seepage prevention net (35); CO2 gas enters the sealed filling chamber in sequence through the horizontal filling pipeline (31), the bottom branch pipe (32), the gas supply regulating valve (33), the high-pressure resistant flexible pipe (34), and the gas seepage prevention net (35).

2. A spatial carbon fixation system for metal mines based on upward filling in segmented stopes according to claim 1, characterized in that, The sealed filling chamber is formed by the low-permeability crystalline surrounding rock (1) on both sides of the staged blasting mining area, the unblasted ore body (7) in the middle stage, and the low-permeability reinforced concrete bottom slab (12), the seepage prevention filling retaining wall (13), and the low-permeability reinforced concrete top slab (19). The low-permeability reinforced concrete base plate (12) is set at the bottom of the staged blasting mining area, and the low-permeability reinforced concrete base plate (12) and the bottom of the unblasted ore body (7) in the middle stage form the middle stage access roadway (6). The low-permeability reinforced concrete roof slab (19) is set at the top of the staged blasting mining area, and is fixed on both sides to the top of the low-permeability crystalline surrounding rock (1) and the unblasted ore body (7) in the middle stage, respectively. The seepage-proof filling retaining wall (13) is set between the unblasted ore body (7) in the middle stage and the low-permeability reinforced concrete base plate (12), and the two ends of the seepage-proof filling retaining wall (13) are fixedly connected to the unblasted ore body (7) in the middle stage and the low-permeability reinforced concrete base plate (12) respectively.

3. A spatial carbon fixation system for metal ore based on upward filling in segmented stopes according to claim 2, characterized in that, The low-permeability reinforced concrete roof slab (19) is provided with a CO2 pipe hole (20), a filling pipe hole (21), an observation window (22), and a dual-purpose exhaust / CO2 monitoring hole (24); a portable CO2 monitor (40) is installed at the dual-purpose exhaust / CO2 monitoring hole (24); The filling flexible tube (28) extends into the top of the sealed filling chamber through the filling pipe hole (21); The high-pressure resistant flexible tube (34) extends into the bottom of the sealed filling chamber through the CO2 pipe hole (20); The observation window (22) is used to observe whether the filling slurry is in contact with the bottom of the low-permeability reinforced concrete roof after the filling slurry enters the filling chamber from the filling flexible pipe (28) through the horizontal filling pipe (27) in the previous stage access roadway (8). The exhaust / CO2 monitoring dual-purpose port (24) is used to discharge the gas in the sealed filling chamber after CO2 gas passes through the CO2 horizontal filling pipe (31) in the upper stage approach roadway (8), through the bottom branch pipe (32) and the high pressure resistant flexible pipe (34) into the bottom of the sealed filling chamber. The portable CO2 monitor (40) is used to monitor the gas discharged through the exhaust / CO2 monitoring dual-purpose port (24) to help determine whether the CO2 gas fills the sealed filling chamber.

4. A spatial carbon fixation system for metal ore based on upward filling of segmented stopes according to claim 2, characterized in that, The seepage-proof filling retaining wall (13) is provided with a pressure relief / drainage dual-purpose hole (14); a support structure is provided on the wall surface of the seepage-proof filling retaining wall (13) on the side away from the low-permeability crystalline surrounding rock (1); The support structure includes thick steel plates (15) for diagonal bracing, diagonal bracing (16), several horizontal channel steels (17) at the top of the diagonal bracing, and several horizontal channel steels (18) at the bottom of the diagonal bracing. The diagonal bracing is made of thick steel plate (15) and is installed on the wall surface of the seepage-proof filling retaining wall (13) on the side away from the low-permeability crystalline surrounding rock (1); The horizontal channel steel (17) at the top of the inclined brace is fixedly installed on the wall surface of the thick steel plate (15) for the inclined brace away from the seepage prevention and filling retaining wall (13), and the center line of the horizontal channel steel (17) at the top of the inclined brace is parallel to the low-permeability reinforced concrete base plate (12). The inclined bottom horizontal channel steel (18) is set on the top of the low permeability reinforced concrete base plate (12), and the inclined bottom horizontal channel steel (18) is set inside the intermediate stage access roadway (6). The center line of the inclined bottom horizontal channel steel (18) is parallel to the seepage prevention and filling retaining wall (13). The two ends of the diagonal brace (16) are fixedly connected to the top horizontal channel steel (17) and the bottom horizontal channel steel (18) of the diagonal brace, respectively.

5. A spatial carbon fixation system for metal mines based on upward filling in segmented stopes according to claim 2, characterized in that, The CO2 horizontal filling pipeline (31) is made of seamless steel pipe.

6. A carbon fixation method for a spatial carbon fixation system in a segmented stope based on upward filling, as described in any one of claims 1-5, characterized in that... Includes the following steps: S1: Use blasting barrels (10) to blast the intermediate ore body to form a staged blasting mining area, and perform high-pressure grouting in the fracture zone (3) and dissolution channel (2) in the low-permeability crystalline surrounding rock (1) to form high-pressure grouting sealing (4). S2: Lay a low-permeability reinforced concrete base slab at the bottom of the staged blasting mining area (12). S3: Construct a seepage-proof filling retaining wall (13) in the intermediate-stage access roadway between the intermediate-stage unblasted ore body (7) and the low-permeability reinforced concrete base slab (12), and install a support structure; S4: A low-permeability reinforced concrete roof slab (19) is set between the low-permeability crystalline surrounding rock (1) and the unblasted ore body (7) in the middle stage; at this time, the setting of a closed filling chamber is completed by the low-permeability crystalline surrounding rock (1) of igneous rock or metamorphic rock on both sides of the stage blasting mining area, the unblasted ore body (7) in the middle stage, the low-permeability reinforced concrete bottom slab (12), the seepage prevention filling retaining wall (13), and the low-permeability reinforced concrete roof slab (19); S5: A horizontal filling pipe (27) and a CO2 horizontal filling pipe (31) are installed in the upper-stage access roadway (8) between the top of the sealed filling chamber and the upper-stage unblasted ore body (9); and a filling flexible pipe (28) connected to the horizontal filling pipe (27) is extended into the top of the sealed filling chamber, and a high-pressure resistant flexible pipe (34) is connected to the CO2 horizontal filling pipe (31) and extended into the bottom of the sealed filling chamber; S6: Operate the ground filling station so that the filling slurry enters the filling chamber through the filling flexible pipe (28) via the horizontal filling pipe (27) in the upper stage access roadway (8); until the filling slurry contacts the bottom of the low-permeability reinforced concrete roof slab; S7: CO2 gas is passed through the CO2 horizontal filling pipe (31) in the upper stage approach roadway (8), through the bottom branch pipe (32) and the high pressure resistant flexible pipe (34), and enters the bottom of the sealed filling chamber until the CO2 gas reaches the target filling amount, so as to complete the solidification and sealing of CO2 gas.

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