Method for improving fire extinguishing efficiency of underground filling grouting material

Abstract

The invention discloses a method for improving the fire extinguishing efficiency of an underground filling grouting material, and belongs to the technical field of mine fire prevention and control. The method comprises the following steps: mixing water and pulping raw materials according to a required water-cement ratio to prepare slurry; a chemical foaming agent component A is added into the slurry and fully mixed, then a chemical foaming agent component B is added, the chemical foaming agent component A contains carbonate, the chemical foaming agent component B contains acid, inert gas carbon dioxide is released after the component A and the component B are mixed, and slurry colloid foam is generated; injecting into a coal mine underground goaf through a grouting pipeline to extinguish fire and prevent fire; wherein the addition amount of the chemical foaming agent component A and the chemical foaming agent component B accounts for 5-18% of the weight of the slurry. A chemical foaming mode is adopted, a gas source is provided by means of carbon dioxide generated by chemical reaction of materials, the problem that traditional three-phase foam is insufficient in physical compressed air foaming capacity in long-distance high-position drilling is effectively solved, and the problem of continuous goaf oxygen supply under the condition of physical compressed air foaming is also effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of mine fire prevention and control, and in particular to a method for improving the fire extinguishing efficiency of underground filling grouting materials. Background Art

[0002] Grouting fire prevention and extinguishing technology is to use a grouting pump to transport a slurry made of non-combustible solid materials and water to the designated fire area. The slurry covers the loose coal body to remove heat, cool down, and isolate oxygen. The earliest materials used in coal mine fire prevention and extinguishing materials, such as fly ash and yellow mud slurry, belong to this category. However, this fire prevention and extinguishing technology has the following disadvantages: (1) The slurry is prone to form a "groove" phenomenon in the goaf and cannot be accumulated at high places, so it is not suitable for high-position fire areas; (2) After the water in traditional grouting materials evaporates, the material will dry and crack, and new air leakage channels will be formed on the surface of the coal body; (3) The evaporation of water will interact with the surface of the coal body to release a certain amount of wetting heat, accelerate the oxidation and spontaneous combustion of coal, and bring the risk of water-gas explosion. In order to improve the fire prevention and extinguishing effect, three-phase foam fire prevention and extinguishing technology came into being.

[0003] Three-phase foam is a new type of fire prevention and extinguishing medium that integrates solid (fly ash or yellow mud), liquid (water) and gas (pressurized air) three-phase materials. After the foam is injected into the goaf, the volume of the mud increases rapidly due to the injection of compressed air, and it can accumulate to high places in the goaf, covering both low and high floating coal, and maintaining the stability of the foam for a long time. It makes full use of the covering property of fly ash or yellow mud, the asphyxiation of nitrogen and the heat absorption and cooling property of water for fire prevention and extinguishing, greatly improving the efficiency of fire prevention and extinguishing. However, the foaming method adopted by the three-phase foam is physical and mechanical foaming, which not only requires the equipment of special foaming devices, compressed air devices and other equipment, but also relies on on-site compressed air. The unstable pressure leads to unstable foaming and poor fire extinguishing efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a method for improving the fire extinguishing efficiency of underground filling grouting materials, which does not require a complicated foam preparation system and does not require the introduction of nitrogen or compressed air, and is simple and efficient.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for improving the fire extinguishing efficiency of underground filling grouting materials, comprising the following steps: (1) Mixing water and pulping raw materials into slurry according to the required water-cement ratio; (2) First add chemical foaming agent component A to the slurry, and then add chemical foaming agent component B after sufficient mixing. The chemical foaming agent component A is a powder containing carbonate, and the chemical foaming agent component B is a liquid containing acid. After the chemical foaming agent component A and the chemical foaming agent component B are mixed, inert gas carbon dioxide is released to generate mud colloidal foam, which is injected into the coal mine goaf through the grouting pipeline for fire extinguishing and fire prevention; wherein the addition amount of the chemical foaming agent component A and the chemical foaming agent component B accounts for 5%-18% of the weight of the slurry.

[0006] Preferably, the pulping raw material is fly ash, yellow mud or white mud.

[0007] Preferably, the carbonate is selected from one or more of light calcium carbonate, heavy calcium carbonate, magnesium carbonate, and surface-modified active calcium.

[0008] Preferably, the acid is selected from one or more of citric acid, oxalic acid and tartaric acid.

[0009] Furthermore, the chemical foaming agent component A also contains a thickener, and the amount of the thickener accounts for 10-20% of the total amount of the A material.

[0010] Preferably, the thickener is selected from one or more of sodium carboxymethyl cellulose, polyvinyl pyrrolidone, guar gum, xanthan gum, methyl cellulose, hydroxyethyl methyl cellulose and hydroxypropyl methyl cellulose.

[0011] Furthermore, the chemical foaming agent component B also contains a foam stabilizer, and the amount of the foam stabilizer accounts for 3-7% of the total amount of the B material.

[0012] Preferably, the foam stabilizer is selected from one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide, imidazoline, and fatty acid diethanolamide with a molecular weight of 200-6000.

[0013] Preferably, the water-cement ratio in step (1) is 1.5-2.5.

[0014] Preferably, the mass ratio of the chemical foaming agent component A to the chemical foaming agent component B in step (2) is 1:3-5.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a chemical foaming method, relying on the carbon dioxide generated by the chemical reaction of the material itself to provide the gas source, which effectively solves the problem of insufficient foaming capacity of traditional three-phase foams relying on physical compressed air in long-distance high-position drilling, and also effectively avoids the problem of continuous oxygen supply in the goaf under the condition of physical compressed air foaming; 2. The present invention adopts chemical self-foaming, which does not require the use of special foaming devices, compressed air devices and other equipment, nor does it need to change the existing grouting system of the coal mine. The supporting equipment is light and flexible, not limited by the application site, and the construction process is simple; 3. The slurry prepared by the present invention can diffuse, accumulate and cover in the goaf with foam as the carrier, and can bring more water and mud into the high, middle and low positions of the prevention and control space, while yellow mud, fly ash and the like can also play the role of skeleton support, thickening the solution, and further increasing the foam stabilizing effect and water retention effect of the foam, and finally achieving the treatment of high-position coal waste, avoiding the waste of slurry and the impact on the production of the working face;

[0016] 4. The foam produced by the chemical foaming agent of the present invention has good accumulation and high foam stability. After 48 hours, the foam retention rate is still above 50%; the water retention rate is high, and the water retention rate is still above 50% when the foam remains 50%. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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 any ordinary technician in the field belong to the scope of protection of the present invention.

[0018] The technical concept of the present application is: to make slurry with fly ash, yellow mud and other raw materials, and to release inert gas carbon dioxide by mixing with chemical foaming agent to generate mud colloidal foam. This material has high stability, high water retention and excellent foam accumulation. A small amount of inert gas can be wrapped in the foam and injected into the spontaneous combustion area of ​​the coal mine underground in the form of grouting. When the mud colloidal foam material contacts the spontaneous combustion area, the foam liquid film is ruptured by heat to release water, thereby significantly reducing the temperature inside and on the surface of the spontaneous combustion area, and effectively preventing the spontaneous combustion of coal; at the same time, the foamed fly ash slurry or yellow mud slurry can effectively cover and wrap the surface of the coal body, isolate oxygen, and seal the cracks in the coal body, thereby effectively preventing coal oxidation, and comprehensively achieving the effect of fire prevention and extinguishing.

[0019] Unlike three-phase foam materials, the present invention does not require a complicated foam preparation system, nor does it require the introduction of nitrogen or compressed air. It can be directly applied to the existing grouting system in coal mines. It is not limited by the application site and can avoid the problem of insufficient foaming ability relying on physical compressed air. It is more suitable for high-position fire areas.

[0020] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention. It should also be noted that all raw materials in the present invention, unless otherwise specified, are raw materials known in the art. Example 1

[0021] The chemical foaming agent component A used in this embodiment is: 90% light calcium carbonate, 5% sodium carboxymethyl cellulose, and 5% xanthan gum; the chemical foaming agent component B is 30% oxalic acid, 17% tartaric acid, 3% polyacrylamide, and 50% water.

[0022] Water and yellow mud are mixed in a water-cement ratio of 2.5:1 to prepare yellow mud slurry. The yellow mud slurry is then fully mixed with component A, and then component B is added. Mud foam is generated after mixing and foaming. The mass ratio of component A: component B is 1:3, and the total addition amount of component A and component B accounts for 18% of the weight of the yellow mud slurry. Example 2

[0023] The chemical foaming agent component A used in this embodiment is: light calcium carbonate 80%, magnesium carbonate 9%, methyl cellulose 5%, xanthan gum 6%; the chemical foaming agent component B is oxalic acid 22%, tartaric acid 26%, polyethylene glycol molecular weight 4000 3%, polyvinyl alcohol 1%, and water 48%.

[0024] Water and yellow mud are mixed in a water-cement ratio of 2.5:1 to prepare yellow mud slurry. The yellow mud slurry is then fully mixed with component A, and then component B is added. Mud foam is generated after mixing and foaming. The mass ratio of component A: component B is 1:3, and the total addition amount of component A and component B accounts for 14% of the weight of the yellow mud slurry. Example 3

[0025] The chemical foaming agent component A used in this embodiment is: 50% heavy calcium carbonate, 38% light calcium carbonate, 5% sodium carboxymethyl cellulose, 6% xanthan gum, and 1% methyl cellulose; the chemical foaming agent component B is 20% oxalic acid, 14% tartaric acid, 16% citric acid, 3% polyvinyl alcohol, and 47% water.

[0026] Mix water and yellow mud in a water-cement ratio of 2:1 to prepare yellow mud slurry, then fully mix the yellow mud slurry with component A, then add component B, and mix and foam to generate mud foam. The mass ratio of component A: component B is 1:4, and the total addition amount of component A and component B accounts for 10% of the weight of the yellow mud slurry. Example 4

[0027] The chemical foaming agent component A used in this embodiment is: 50% heavy calcium carbonate, 16% light calcium carbonate, 20% magnesium carbonate, 5% methyl cellulose, 7% xanthan gum, and 2% hydroxyethyl methyl cellulose; the chemical foaming agent component B is 10% oxalic acid, 24% tartaric acid, 13% citric acid, 5% imidazoline, and 48% water.

[0028] Mix water and yellow mud in a water-cement ratio of 2:1 to prepare yellow mud slurry, then fully mix the yellow mud slurry with component A, then add component B, and mix and foam to generate mud foam. The mass ratio of component A: component B is 1:4, and the total addition amount of component A and component B accounts for 12% of the weight of the yellow mud slurry. Example 5

[0029] The chemical foaming agent component A used in this embodiment is: heavy calcium carbonate 70%, magnesium carbonate 12%, hydroxyethyl methylcellulose 8%, guar gum 6%, hydroxypropyl methylcellulose 4%; the chemical foaming agent component B is oxalic acid 5%, tartaric acid 24%, citric acid 21%, polyethylene glycol molecular weight 6000 3%, polyvinyl alcohol 2%, and water 45%.

[0030] Mix water and yellow mud in a water-cement ratio of 1.5:1 to prepare yellow mud slurry, then fully mix the yellow mud slurry with component A, then add component B, and mix and foam to generate mud foam. The mass ratio of component A: component B is 1:5, and the total addition amount of component A and component B accounts for 8% of the weight of the yellow mud slurry. Example 6

[0031] The chemical foaming agent component A used in this embodiment is: 80% heavy calcium carbonate, 7% polyvinyl pyrrolidone, 8% guar gum, and 5% xanthan gum; the chemical foaming agent component B is 25% tartaric acid, 25% citric acid, 3% polyacrylamide, 2% fatty acid diethanolamide, and 45% water.

[0032] Mix water and yellow mud in a water-cement ratio of 1.5:1 to prepare yellow mud slurry, then fully mix the yellow mud slurry with component A, then add component B, and mix and foam to generate mud foam. The mass ratio of component A: component B is 1:5, and the total addition amount of component A and component B accounts for 5% of the weight of the yellow mud slurry. Example 7

[0033] The chemical foaming agent component A used in this embodiment is: 50% heavy calcium carbonate, 38% light calcium carbonate, 5% carboxymethyl cellulose, 6% xanthan gum, and 1% methyl cellulose ether; the chemical foaming agent component B is 20% oxalic acid, 14% tartaric acid, 16% citric acid, 3% polyvinyl alcohol, and 47% water.

[0034] Water and fly ash are mixed in a water-cement ratio of 2:1 to prepare fly ash slurry. The fly ash slurry is then fully mixed with component A, and then component B is added. Mud foam is generated after mixing and foaming. The mass ratio of component A: component B is 1:4, and the total addition amount of component A and component B accounts for 10% of the weight of the yellow mud slurry. Example 8

[0035] The chemical foaming agent component A used in this embodiment is: 50% heavy calcium carbonate, 38% light calcium carbonate, 5% carboxymethyl cellulose, 6% xanthan gum, and 1% methyl cellulose ether; the chemical foaming agent component B is 20% oxalic acid, 14% tartaric acid, 16% citric acid, 3% polyvinyl alcohol, and 47% water.

[0036] Water and white mud are mixed in a water-cement ratio of 2.5:1 to prepare white mud slurry. The white mud slurry is then fully mixed with component A, and then component B is added. Mud foam is generated after mixing and foaming. The mass ratio of component A: component B is 1:3, and the total addition amount of component A and component B accounts for 10% of the weight of the yellow mud slurry.

[0037] The mud colloid foam prepared in Examples 1 to 8 of the present invention was tested for performance: stacking, foaming multiple, foam stability, and water retention. The data tested in different examples are shown in Table 1: (1) Stacking test: Prepare mud colloidal foam in a 500 mL glass beaker. After the foam height stops increasing, slowly tilt the beaker 90 degrees to observe the state after foaming. If the porous structure does not slide at all after foaming, it has stacking properties.

[0038] (2) Foaming multiple test: The volume V1 of the slurry plus component A and component B before the reaction is measured in advance as the initial reaction volume. The volume after foaming is recorded as V2 after testing, and the foaming multiple is V2 / V1.

[0039] (3) Foam stability test: Start timing from the beginning of foaming, and observe the time it takes for the volume to return to the volume before foaming, which is the foam stability time.

[0040] (4) Water retention rate test: The mass of the foam after foaming is recorded as M1. When the foam remains at 50%, the mass excluding the water in the lower layer is recorded as M2. The water retention rate is (M1-M2) / M1*100%.

[0041] Table 1 Performance of foaming agents for achieving fire extinguishing function by chemical foaming method Example Accumulation Foaming multiple Foam stability / h Water retention rate Example 1 Stackable 6.5 55 58% Example 2 Stackable 7.2 69 74% Example 3 Stackable 7.8 60 66% Example 4 Stackable 8.3 51 55% Example 5 Stackable 8.8 50 51% Example 6 Stackable 7.5 64 68% Example 7 Stackable 3.4 58 63% Example 8 Stackable 5.7 55 60% As can be seen from Table 1, the mud colloidal foam prepared by the method of the present invention has good stacking properties, can reach the upper, middle and lower positions of the treatment space in the broken coal rock mass, greatly improving the effective coverage of the mud; and has an excellent foaming multiple and high foam stability, which can effectively avoid the loss and collapse of the mud; the water retention rate is high, and the water retention rate is still above 50% when the foam remains 50%, and the high-water-content foam slowly releases water in a high-temperature dry environment, continuously and stably cools down, and ensures the cooling efficiency.

[0042] Practical Application 1 A mine in Gansu 6225 -1Fire prevention and extinguishing project at the working face. In actual management, in the bottom extraction lane to 6225 -1 High-level grouting drilling holes are arranged in the goaf, with a spacing of 50m between drilling holes. The original yellow mud grouting system of the mine is used, and chemical foaming agents are added to fill and cover the high-level coal residues in the goaf. By adding chemical foaming agents, the yellow mud slurry forms a foam + gel state. The role of the foam is to improve the diffusion and accumulation ability of the yellow mud slurry, so as to achieve the effect of accumulation and covering the high-level floating coal. The role of the gel is to increase the viscosity of the yellow mud slurry, lock the water in the yellow mud slurry in the form of solid gel, form a yellow mud gel covering layer, and wrap the oxidized coal residues in the goaf, achieving 6225 -1 Large-scale covering and cooling of high-level coal residues in goaf areas.

[0043] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for improving the fire extinguishing efficiency of underground filling grouting materials, characterized in that: The following steps are involved: (1) Mixing water and pulping raw materials into slurry according to the required water-cement ratio; (2) First add chemical foaming agent component A to the slurry, and then add chemical foaming agent component B after sufficient mixing. The chemical foaming agent component A is a powder containing carbonate, and the chemical foaming agent component B is a liquid containing acid. After the chemical foaming agent component A and the chemical foaming agent component B are mixed, inert gas carbon dioxide is released to generate mud colloidal foam, which is injected into the coal mine goaf through the grouting pipeline for fire extinguishing and fire prevention; wherein the addition amount of the chemical foaming agent component A and the chemical foaming agent component B accounts for 5%-18% of the weight of the slurry.

2. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1, characterized in that: The pulping raw material is selected from fly ash, yellow mud or white mud.

3. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1 or 2, characterized in that: The carbonate is selected from one or more of light calcium carbonate, heavy calcium carbonate, magnesium carbonate, and surface-modified active calcium.

4. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1 or 2, characterized in that: The acid is selected from one or more of citric acid, oxalic acid and tartaric acid.

5. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1 or 2, characterized in that: The chemical foaming agent component A also contains a thickener, and the amount of the thickener accounts for 10-20% of the total amount of component A.

6. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 5, characterized in that: The thickener is selected from one or more of sodium carboxymethyl cellulose, polyvinyl pyrrolidone, guar gum, xanthan gum, methyl cellulose, hydroxyethyl methyl cellulose and hydroxypropyl methyl cellulose.

7. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1 or 2, characterized in that: The chemical foaming agent component B also contains a foam stabilizer, and the amount of the foam stabilizer accounts for 3-7% of the total amount of component B.

8. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 7, characterized in that: The foam stabilizer is selected from one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide, imidazoline and fatty acid diethanolamide with a molecular weight of 200-6000.

9. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1 or 2, characterized in that: The water-cement ratio in step (1) is 1.5-2.

5.

10. A method for improving the fire extinguishing efficiency of underground filling grouting materials according to claim 1 or 2, characterized in that: The mass ratio of the chemical foaming agent component A to the chemical foaming agent component B in step (2) is 1:3-5.