A method for treating alkaline mine water using carbon dioxide sequestration gob area

Abstract

The present application relates to a kind of methods for treating alkaline mine water using carbon dioxide storage goaf, which uses the property that alkaline water can react with carbon dioxide to achieve the purpose of purifying waste alkaline mine water.In underground coal mine, strip filling goaf is set up, water tank is dug on the ground of strip filling goaf, and water pump and carbon dioxide gas delivery pipe are installed in strip filling goaf to ensure the injection of carbon dioxide gas from the surface into goaf and the injection and extraction of mine water.By means of water injection pump, waste alkaline mine water is injected into carbon dioxide storage goaf, and after the alkaline mine water in carbon dioxide storage goaf reaches the preset time, the neutralized mine water is pumped out by water extraction pump, realizing acid-base neutralization and reuse of alkaline mine water.

Description

Technical Field

[0001] This invention belongs to the field of alkaline mine water treatment technology, specifically relating to a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas. Background Technology

[0002] With the advancement of industry and technology in modern times, the greenhouse effect has intensified, posing a significant threat to human survival and development. The main gas contributing to the greenhouse effect is carbon dioxide. Carbon dioxide absorbs solar radiation reflected from the Earth, thus achieving a warming effect. The greater the amount of carbon dioxide, the stronger its warming ability. Therefore, it is urgent to reduce carbon dioxide emissions and improve carbon dioxide utilization efficiency to lower the concentration of carbon dioxide in the atmosphere.

[0003] Mine water refers to groundwater near the mine that is polluted during coal mining due to chemical and physical changes caused by coal seams, surface rock strata, and human activities. It encompasses all water that seeps into the underground mining space. Therefore, mine water is typically black and contains a large amount of suspended solids, primarily coal dust particles, along with some rock dust and clay. It generally does not contain toxic substances. This leads to mine water discharge problems, becoming a major source of mine environmental pollution. The annual mine water inflow from coal mining exceeds 2 billion cubic meters, polluting a wide area. In many parts of my country, the pH value of mine water is high. Therefore, this invention combines alkaline mine water treatment technology with carbon dioxide utilization technology, proposing a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas.

[0004] Currently, coal mine water treatment technologies mainly include: flocculation to remove suspended particulate matter, reverse osmosis to remove soluble salts, and neutralization of acidic water, as well as combinations thereof. Flocculation to remove suspended particulate matter (such as CN101786760B) requires large dosages, and the resulting flocculent precipitates are difficult to treat and prone to secondary pollution if not handled properly. Reverse osmosis to remove soluble salts (CN201085961Y) has high initial investment and ongoing operation and maintenance costs; existing commonly used filter cartridges have low removal rates for most salts, and the treated mine water remains alkaline, failing to meet discharge standards. Neutralization of acidic water mainly uses lime or limestone as a neutralizing agent, with the neutralization products precipitated in a sedimentation tank for removal; however, this process is often economically infeasible. Based on the above issues with carbon dioxide geological sequestration technology and mine water treatment, a method for treating alkaline mine water using carbon dioxide sequestration in goaf areas is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for treating alkaline mine water in goaf areas using carbon dioxide sequestration, thereby treating alkaline mine water, one of the sources of mine pollution, to meet discharge standards. Strongly alkaline and weakly acidic rock minerals (such as potassium feldspar and calcium feldspar) in Northwest China undergo hydrolysis upon contact with water, resulting in a chemical reaction that increases the pH value of the mine water and the mass concentration of calcium and sodium ions. Introducing carbon dioxide lowers the concentration of alkaline metal ions in the mine water. The basic principle is that carbon dioxide dissolves in water to produce carbonate ions, which further react with alkaline metal ions in the mine water. The reaction formula is as follows:

[0006] CO2 + 2(OH) - →CO2-3+2H2O (1)

[0007] Utilizing the above principles, one of the problems of mine environmental pollution can be solved, further reducing mine pollution and improving mine environmental protection measures, thereby contributing to the realization of green mines. Another objective of this invention is to provide a method for treating alkaline mine water in goaf areas using carbon dioxide sequestration.

[0008] To achieve the above objectives, the present invention provides a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas. The method includes a water supply pipe, a water level display, a strip filling body, a water injection tank, a clean water tank, a water injection pump, a water pump, a clean water level monitoring sensor, and a working water level monitoring sensor. The water supply pipe penetrates from the roof of the carbon dioxide sequestration goaf to the surface, delivering alkaline mine water into the goaf. The bottom of the water supply pipe extends to the water injection trough on the coal seam floor. Clean water troughs are excavated on both sides of the bottom of the strip filling body. Both the clean water trough and the water injection trough need to be coated with waterproof paint to prevent leakage. The water injection pump and the water pump are installed on the side of the water supply pipe that passes through the coal seam floor and must be completely submerged in water during use. This method is intended to prevent gas leakage within the carbon dioxide sequestration goaf. The clean water level monitoring sensor and the working water level monitoring sensor are connected to the surface water level display via a waterproof wiring harness through the water supply pipe. When the water level reaches the monitoring sensor line, the water level display above will show the corresponding reading.

[0009] Preferably, the water supply pipe is sealed at the top plate and has a sealing collar at the connection with the water pump and the water injection pump.

[0010] Preferably, the water purification tank is excavated in the middle of the bottom of the two filling bodies. The specific width of the water purification tank should be set according to the geological data of the mine. At the same time, the water purification tank and the water injection tank need to be coated with waterproof paint to prevent leakage.

[0011] Preferably, the water injection tank is at least 0.5m deeper than the clean water tank towards the bottom of the coal seam. The water pump and water injection pump are completely submerged below the clean water level monitoring sensor during installation and must be completely immersed in water during use. This is intended to prevent gas leakage in the carbon dioxide sequestration goaf.

[0012] Preferably, the alkaline mine water needs to be left in the purification tank for a period of time before being pumped out by the pumping pipe to neutralize the mine water.

[0013] The method for treating alkaline mine water in goaf areas using carbon dioxide sequestration includes the following steps:

[0014] S1. Arrange strip filling for the goaf based on the actual geological data of the goaf area in the mine;

[0015] S2. Construct water supply pipelines, pumping pipes, and conveying pipes on the surface leading to the strip-filled goaf area;

[0016] S3. Open the control valve and inject carbon dioxide gas into the strip filling goaf area through the surface delivery pipe to seal the carbon dioxide, then close the control valve.

[0017] S4. The alkaline mine water that needs to be neutralized is transported to the carbon dioxide storage goaf area through the water pipeline, and then injected into the water injection tank by the water injection pump to fill the water injection tank.

[0018] S5. When the height of the alkaline mine water in the injection tank is the same as the bottom of the clean water tank, the clean water level monitoring sensor sends a signal and the water level display makes a corresponding display. At this time, the water in the injection tank begins to slowly flow into the clean water tank.

[0019] S6. Continue adding water to the alkaline mine water purification tank until the working water level monitoring sensor sends a signal and the water level display shows the corresponding information. At this point, stop adding water to the purification tank, turn off the water pump, and allow the alkaline mine water to remain in the carbon dioxide sequestration goaf for the appropriate time to fully neutralize it.

[0020] S7. When the alkaline mine water has been stored in the carbon dioxide sequestration goaf for the required time, the water pump should be turned on to draw the neutralized alkaline mine water out of the water tank through the water pipe for irrigation of mine vegetation or other uses.

[0021] S8. It should be noted that when the water pump is drawing water from the neutralized mine water in the carbon dioxide sequestration goaf, the water level display should be turned off after the water level monitoring sensor sends a signal and the water level display shows the corresponding display. This is because the water pump and the water injection pump need to be completely immersed in water when in use. This is intended to prevent gas leakage in the carbon dioxide sequestration goaf.

[0022] S9. Under the premise of ensuring safety and preventing leakage, steps S3 to S8 can be repeated.

[0023] Preferably, in S2 and S5, the water injection pump is connected to the switch control button next to the water level display via a waterproof wiring harness through a water supply pipe, and the water pump is connected to the switch control button next to the water level display via a waterproof wiring harness through a water pumping pipe.

[0024] Preferably, in step S7, the neutralized alkaline mine water can be used for irrigation of green plants in the mine environment or for other purposes;

[0025] Preferably, in step S8, the pumping pump and the injection pump are completely submerged below the net water level monitoring sensor during installation, and must be completely immersed in water during use. This is intended to prevent gas leakage from the carbon dioxide sequestration goaf.

[0026] The advantages and positive effects of the method for treating alkaline mine water by using carbon dioxide sequestration in the goaf, as described in this invention, are as follows: Alkaline mine water, one of the sources of mine pollution, can be neutralized by acid and alkali in the goaf by carbon dioxide sequestration, thereby reducing mine environmental pollution and being used for green construction of the mine environment. This solves the problem of alkaline mine water pollution, improves the quality of the mine environment, and accelerates the green construction of the mine.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 A floor strip filling diagram for a method of treating alkaline mine water using carbon dioxide sequestration in goaf areas.

[0029] Figure 2 This is a roof view of a method for treating alkaline mine water in goaf using carbon dioxide sequestration.

[0030] Figure 3 This is a three-dimensional diagram of a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas.

[0031] Figure 4 This is a longitudinal cross-sectional view of a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas.

[0032] Figure 5 This is a cross-sectional view of a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas.

[0033] Attached Figure

[0034] 1. Filling body, 2. Water injection tank, 3. Clean water tank, 4. Pumping tank, 5. Water level display, 6. Water delivery pipe, 7. Control valve, 8. Delivery pipe, 9. Pumping pipe, 10. Roof strata, 11. Pumping pump, 12. Water injection pump, 13. Coal seam, 14. Coal seam floor, 15. Pressure injection pipe, 16. Working water level monitoring sensor, 17. Clean water level monitoring sensor. Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. Example

[0037] Figure 1 This is a diagram of the bottom strip filling for a method of treating alkaline mine water by using carbon dioxide to seal in goaf areas. Figure 2 This is a roof view of a method for treating alkaline mine water in goaf using carbon dioxide sequestration. Figure 3 This is a three-dimensional diagram of a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas. Figure 4 This is a longitudinal cross-sectional view of a method for treating alkaline mine water by using carbon dioxide to seal in goaf areas. Figure 5This is a cross-sectional view of a method for treating alkaline mine water by using carbon dioxide sequestration in a goaf. As shown in the figure, the method for treating alkaline mine water by using carbon dioxide sequestration in a goaf includes a water supply pipe 6, a water level display 5, a filling body 1, a water injection tank 2, a water pumping tank 4, a clean water tank 3, a clean water level monitoring sensor 17, a water injection pump 12, a working water level monitoring sensor 16, and a water pump 11. A strip-filled goaf is constructed within the mine goaf area, and a water supply pipe 6, a pumping pipe 9, and a delivery pipe 8 are established leading from the strip-filled goaf to the surface. A control valve 7 is opened to inject carbon dioxide gas into the strip-filled goaf through the surface delivery pipe 8 for carbon dioxide sequestration. The water supply pipe 6 penetrates from the roof strata 10 of the carbon dioxide-sequestrated goaf to the surface, delivering alkaline mine water into the goaf. The bottom of the water supply pipe 6 extends to the water injection trough 2 at the coal seam floor 14. A clean water trough 3 is excavated between the bottoms of the two strip-filled bodies 5. The clean water trough 3, water injection trough 2, and pumping trough 4 are coated with waterproof paint to prevent leakage. The water injection pump 12 is installed on the side of the water supply pipe 6 near the coal seam floor 14 and below the clean water level. The water level sensor 17 and the water pump 11 are installed on the side of the water pumping pipe 9 near the coal seam floor 14 and below the clean water level sensor 17. Both need to be completely submerged in water during use. This method is intended to prevent gas leakage in the carbon dioxide sequestration goaf. The water injection pump 12 is connected to the switch control button next to the water level display table 5 via a waterproof wiring harness through the water supply pipe 6. The water pump 11 is connected to the switch control button next to the water level display table 5 via a waterproof wiring harness through the water pumping pipe 9. The clean water level sensor 17 and the working water level sensor 16 are connected to the surface water level display table 5 via a waterproof wiring harness through the water supply pipe. At the same time, when the water level reaches the monitoring sensor line, the water level display table 5 above will display accordingly.

[0038] Water injection tank 2 and water extraction tank 4 are at least 0.5m deeper than the clean water tank 3 towards the coal seam floor 7. Water pump 11 and water injection pump 12 are completely submerged below the clean water level monitoring sensor 17 during installation and must be completely immersed in water during use. This is to prevent gas leakage from the carbon dioxide sequestration goaf. The alkaline mine water needs to be retained in the clean water tank 3 for a period of time before being pumped out by water pump 11 through the extraction pipe 9 to neutralize the water. The neutralized alkaline mine water is then extracted for use in irrigating mine vegetation or for other purposes.

[0039] A method for treating alkaline mine water in goaf areas using carbon dioxide sequestration includes the following steps:

[0040] S1. Arrange strip filling for the goaf based on the actual geological data of the goaf area in the mine;

[0041] S2. Construct water supply pipelines, pumping pipes, and conveying pipes on the surface leading to the strip-filled goaf area;

[0042] S3. Open the control valve and inject carbon dioxide gas into the strip filling goaf area through the surface delivery pipe to seal the carbon dioxide, then close the control valve.

[0043] S4. The alkaline mine water that needs to be neutralized is transported to the carbon dioxide storage goaf area through the water pipeline, and then injected into the water injection tank by the water injection pump to fill the water injection tank.

[0044] S5. When the height of the alkaline mine water in the injection tank is the same as the bottom of the clean water tank, the clean water level monitoring sensor sends a signal and the water level display makes a corresponding display. At this time, the water in the injection tank begins to slowly flow into the clean water tank.

[0045] S6. Continue adding water to the alkaline mine water purification tank until the working water level monitoring sensor sends a signal and the water level display shows the corresponding information. At this point, stop adding water to the purification tank, turn off the water pump, and allow the alkaline mine water to remain in the carbon dioxide sequestration goaf for the appropriate time to fully neutralize it.

[0046] S7. When the alkaline mine water has been stored in the carbon dioxide sequestration goaf for the required time, the water pump should be turned on to draw the neutralized alkaline mine water out of the water tank through the water pipe for irrigation of mine vegetation or other uses.

[0047] S8. It should be noted that when the water pump is drawing water neutralized in the carbon dioxide sequestration goaf, the water level display should be turned off after the water level monitoring sensor sends a signal and the water level display shows the corresponding information. This is because the water pump and the injection pump need to be completely submerged in water during use. This is intended to prevent gas leakage in the carbon dioxide sequestration goaf. Therefore, this invention provides a method for treating alkaline mine water using carbon dioxide sequestration goaf, which treats alkaline mine water, one of the sources of mine pollution, and allows the treated mine water to be used to irrigate mine vegetation, thereby solving the problem of alkaline mine water pollution, improving the quality of the mine environment, and accelerating the green construction of the mine.

[0048] S9. Under the premise of ensuring safety and preventing leakage, steps S3 to S8 can be repeated.

[0049] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for treating alkaline mine water in goaf areas using carbon dioxide sequestration, characterized in that: Includes the following steps: S1. Arrange strip filling for the goaf based on the actual geological data of the goaf area in the mine; S2. Construct water supply pipelines, pumping pipes, and conveying pipes on the surface leading to the strip-filled goaf area; S3. Open the control valve and inject carbon dioxide gas into the strip filling goaf area through the surface delivery pipe to seal the carbon dioxide, then close the control valve. S4. The alkaline mine water that needs to be neutralized is transported to the carbon dioxide storage goaf area through the water pipeline, and then injected into the water injection tank by the water injection pump to fill the water injection tank. S5. When the height of the alkaline mine water in the injection tank is the same as the bottom of the clean water tank, the clean water level monitoring sensor sends a signal, and the water level display shows the corresponding information. At this time, the water in the injection tank begins to slowly flow into the clean water tank. The clean water tank is dug in the middle of the bottom of the two backfill bodies. The specific width of the clean water tank should be set according to the mine geological data. At the same time, the clean water tank and the injection tank need to be coated with waterproof paint to prevent leakage. The injection tank is more than 0.5m deeper than the clean water tank on the side of the coal seam floor. S6. Continue adding water to the alkaline mine water purification tank until the working water level monitoring sensor sends a signal and the water level display shows the corresponding information. At this point, stop adding water to the purification tank, turn off the water pump, and allow the alkaline mine water to remain in the carbon dioxide sequestration goaf for the appropriate time to fully neutralize it. S7. When the alkaline mine water has been stored in the carbon dioxide sealed goaf for the corresponding time, the water pump needs to be turned on to draw the neutralized alkaline mine water out of the water pumping tank through the water pumping pipe for irrigation of mine green plants or other uses. The water pumping tank is more than 0.5m deeper than the clean water tank on the side of the coal seam floor. S8. It should be noted that when the water pump is drawing the neutralized mine water in the carbon dioxide sequestration goaf, the water level display should be turned off after the water level monitoring sensor sends a signal and the water level display shows the corresponding display. This is because the water pump and the water injection pump need to be completely immersed in water when in use. This is intended to prevent gas leakage in the carbon dioxide sequestration goaf. S9. Under the premise of ensuring safety and preventing leakage, repeat steps S3 to S8.

2. The method for treating alkaline mine water in goaf areas using carbon dioxide sequestration according to claim 1, characterized in that: In step S3, the control valve controls the opening and closing of the delivery pipe.

3. The method for treating alkaline mine water in goaf areas using carbon dioxide sequestration according to claim 1, characterized in that: In steps S4 and S5, the pumping pump and the injection pump are completely submerged below the net water level monitoring sensor during installation and must be completely immersed in water during use. This is intended to prevent gas leakage from the carbon dioxide sequestration goaf.

4. The method for treating alkaline mine water in goaf areas using carbon dioxide sequestration according to claim 1, characterized in that: In steps S4 and S8, the clean water level monitoring sensor and the working water level monitoring sensor are connected to the surface water level display via a water supply pipe using a waterproof wiring harness. Simultaneously, when the water level reaches the monitoring sensor line, the water level display above will show the corresponding information.

5. A method for treating alkaline mine water in goaf areas using carbon dioxide sequestration according to claim 1, characterized in that: In steps S6 and S8, the water injection pump is connected to the switch control button next to the water level display via a waterproof wiring harness through a water supply pipe, and the water pump is connected to the switch control button next to the water level display via a waterproof wiring harness through a water pumping pipe.

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