A high-permeability temperature-sensitive inverse phase change gel for mining, preparation method and application

Abstract

The present invention discloses a high-permeability temperature-sensitive reverse phase change gel for mining, a preparation method and an application, and belongs to the technical field of fire prevention and extinguishing in coal mine goaf areas. The silica gel is combined with temperature-controlled flame-retardant microcapsules, and the salting-out effect of silica colloid and the temperature-controlled release of the temperature-sensitive microcapsules are utilized to achieve the temperature-sensitive reverse phase change effect of the inorganic gel. The temperature-sensitive microcapsules are prepared by a melt-dispersion-condensation method using a temperature-sensitive phase change material as a wall material and a high-purity inorganic salt inhibitor as a core material; if the high-temperature point of the coal seam is heated to 75-90°C, the wall shell of the temperature-sensitive microcapsule melts, releasing the inhibitor salt powder to react with silicate to promote the precipitation of silicate, so that the viscous silica gel undergoes a reverse phase change under high temperature conditions, resulting in gel dilution, which increases the permeability of the gel under high temperature conditions, and the diluted gel can penetrate into the interior of the high-temperature coal and form a secondary synergistic inhibitory effect with the inhibitor salt solution, thereby achieving three-dimensional fire prevention and extinguishing and gradient flame retardancy of the gel on the coal body.

Description

Technical Field

[0001] The present invention relates to the technical field of fire prevention and extinguishing in coal mine gob areas, and particularly relates to a high-permeability temperature-sensitive inverse phase change gel for mine use, a preparation method thereof, and an application thereof. Background Art

[0002] Spontaneous combustion of coal is one of the major disasters threatening coal safety. Coal will undergo an oxidation reaction with oxygen in an aerobic environment and accumulate heat, resulting in a slow rise in coal temperature. When the coal temperature exceeds the critical temperature, the coal temperature will rise sharply and spontaneous combustion will occur. Spontaneous combustion of coal not only damages coal resources, but also triggers major accidents such as mine fires and gas explosions, posing a huge threat to the life safety of underground workers and equipment safety. In order to create a safe mining environment, effective prevention and control measures must be taken against the problem of coal spontaneous combustion.

[0003] The caving voids and separation fissures formed after the collapse of the void area in the mine gob area provide a large number of air leakage channels for the residual coal in the gob area, resulting in the gob area becoming the area most prone to coal spontaneous combustion in coal mines, and 60% of spontaneous combustion fires occur in the gob area. The gel fire prevention and extinguishing technology has good mechanical properties and water retention properties, can play a certain role in plugging leaks in fissures, and play a good role in isolating and cooling the coal body. At present, organic gels are widely sourced, easily degradable, and can achieve a phase change effect, but they also have the characteristics of high cost, difficult transportation, and poor fluidity. Inorganic gels have low cost, fast gelation speed, and good fluidity, but they also have disadvantages such as inability to control temperature and difficult degradation. In addition, compared with grouting for fire prevention and extinguishing, gel fire prevention and extinguishing has the disadvantage that the viscosity is too high to penetrate deep into the coal body.

[0004] The patent CN113174270A proposes a temperature-sensitive phase change gel material for inhibiting coal spontaneous combustion, which has a relatively low initial viscosity at low temperature and can transport cell coat inhibitor. When it encounters a high-temperature coal body, the viscosity becomes larger, but this method does not solve the problem that the gel cannot penetrate deep into the residual coal.

[0005] Therefore, it is very necessary to find a fire prevention and extinguishing gel material that is environmentally friendly, non-toxic, economically reasonable, and can penetrate deep into the coal body at high temperature. Summary of the Invention

[0006] In order to solve the deficiencies of the prior art, the present invention provides a high-permeability temperature-sensitive inverse phase change gel for mine use, a preparation method thereof, and an application thereof. The gel material is composed of the most common silicate gel wrapped with temperature-controlled flame-retardant microcapsules, and is in a gel state with a relatively high viscosity in the initial state; when passing through the high-temperature point of the fire area, the microcapsule shell melts and releases the inorganic salt inhibitor therein, which reacts with the silicate gel, resulting in an inverse phase change of the gel, and the viscosity gradually decreases. The diluted gel and the inorganic salt inhibitor form a sol-inorganic salt composite inhibitor liquid system, which seeps into the high-temperature fissures, playing a synergistic flame-retardant effect. The components used do not pollute the environment, are non-toxic and harmless, are widely sourced, and the cost is controllable.

[0007] To solve the above technical problems, the present invention provides a method for preparing a high-permeability temperature-sensitive inverse phase change gel for mine use, and the steps are as follows:

[0008] S1. Heat the temperature-sensitive phase change material to a molten state;

[0009] S2. Under the condition of an inert gas atmosphere, gradually add an inorganic salt inhibitor to the molten temperature-sensitive phase change material in portions and stir evenly, so that the inorganic salt inhibitor particles are evenly distributed in the molten temperature-sensitive phase change material. During the stirring process, it is necessary to ensure that the temperature is 4°C to 8°C higher than the phase change temperature of the temperature-sensitive phase change material to ensure that the temperature-sensitive phase change material is always in a molten state; the inorganic salt inhibitor is in a powder state, and the weight ratio of the temperature-sensitive phase change material to the added inorganic salt inhibitor is: 30 to 40 parts of the temperature-sensitive phase change material, 60 to 70 parts of the inorganic salt inhibitor, and the temperature-sensitive phase change material is a hydrophobic temperature-sensitive wall material;

[0010] S3. Add gelatin and Span 80 to the mixed liquid, stir evenly, and then cool down to obtain a solid product, where the gelatin is 0.3 to 0.8 parts and the Span 80 is 0.3 to 0.8 parts;

[0011] S4. Crush and grind the solid product into solid particles with a particle size of 40 to 60 mesh. The solid particles are temperature-sensitive microcapsules. The temperature-sensitive microcapsules are structures in which the temperature-sensitive phase change material wraps the inorganic salt inhibitor. Since some temperature-sensitive microcapsules cannot ensure that the temperature-sensitive phase change material completely wraps the inorganic salt inhibitor during the preparation process, the crushed and ground solid particles are placed in cold water for 5 to 10 minutes to wash away the acidic salt powder that is not completely wrapped by the temperature-sensitive phase change material and the acidic salt powder leaked during crushing, and then dried for later use;

[0012] S5. Add the dried temperature-sensitive microcapsules to the sodium silicate solution and mix evenly. The mass ratio of the temperature-sensitive microcapsules to the sodium silicate solution is 1:5 to 1:8, and the mass concentration of the sodium silicate solution is 2% to 4%; then add an acidic substance to the sodium silicate solution to react with the sodium silicate to produce a gel, and through a double decomposition reaction, use the principle of strong acid making weak acid to form a silicic acid gel from the sodium silicate, so that the temperature-sensitive microcapsules are evenly distributed in the silicic acid gel to form a high-permeability temperature-sensitive inverse phase change gel;

[0013] Furthermore, the temperature-sensitive phase change material has hydrophobicity and includes one or more mixtures of 70# chlorinated paraffin, 52# chlorinated paraffin, polyethylene glycol, polyvinyl chloride, ethyl cellulose, and pentaerythritol stearate. The temperature-sensitive phase change material is determined according to the required melting point, and the melting point should be determined according to the self-heating critical temperature of the coal from the slow oxidation stage to the rapid oxidation and temperature rise stage. For lignite, it is less than 75°C, for bituminous coal, it is less than 80°C, and for anthracite, it is less than 90°C.

[0014] Furthermore, the inert gas includes nitrogen, helium, and carbon dioxide;

[0015] Furthermore, the inorganic salt inhibitor includes one or more of ammonium chloride, magnesium chloride, sodium chloride, and ammonium dihydrogen phosphate. The inorganic salt inhibitor added to the thermosensitive phase change material is in a granular structure with a particle size of 80 - 120 mesh.

[0016] Furthermore, the modulus of sodium silicate is 2 - 3.

[0017] Furthermore, the acidic substances include sodium bicarbonate, acetic acid, hydrochloric acid, ammonium chloride, and ammonium sulfate.

[0018] A mine - used highly - permeable thermosensitive inverse - phase - change gel prepared by a preparation method of a mine - used highly - permeable thermosensitive inverse - phase - change gel.

[0019] An application of a mine - used highly - permeable thermosensitive inverse - phase - change gel, using a pipeline to transport the mine - used highly - permeable thermosensitive inverse - phase - change gel to the gob area and the easily - self - igniting coal seam, and making the mine - used highly - permeable thermosensitive inverse - phase - change gel cover all the left coal and stay covering the high - temperature area. If the temperature of the high - temperature point in the coal seam rises to 75 - 90 °C, reaching the phase - change temperature, the thermosensitive phase - change material in the microcapsules of the mine - used highly - permeable thermosensitive inverse - phase - change gel melts, releasing the inorganic salt inhibitor to react with the silicic acid gel, prompting the silicic acid gel to thin. Silicic acid is a sol with negative ions. After adding the electrolyte inhibitor, cations will prompt the precipitation of silicic acid, making the gel thin and increasing its permeability. At the same time, an inhibitor solution is formed to penetrate deep into the coal seam to extinguish the fire. The viscous silicic acid gel undergoes an inverse phase - change at high temperature, resulting in gel thinning, significantly increasing the permeability of the gel at high temperature. The released inorganic salt inhibitor forms an inhibitor solution to penetrate deep into the coal seam to extinguish the fire together with the thinned gel, solving the problem that traditional gels cannot penetrate deep into the left coal due to too high viscosity to cool the coal body, and realizing the three - dimensional fire prevention and gradient flame retardancy of the gel for the coal body.

[0020] Furthermore, when the dip angle of the coal seam is greater than 25 degrees, a thickener is added to the sodium silicate solution to increase the viscosity of the inorganic thermosensitive phase - change suspension. The thickener includes sodium polyacrylate and polyacrylamide.

[0021] Application of a high-permeability temperature-sensitive inverse phase change gel for mining. Inject the high-permeability temperature-sensitive inverse phase change gel for mining upstream of the suspected fire area in the goaf to make the gel cover the residual coal in the goaf. If the high-permeability temperature-sensitive inverse phase change gel for mining encounters a high-temperature point on the coal body, after the temperature of the high-temperature point on the coal body exceeds the melting temperature of the temperature-sensitive outer layer of the temperature-sensitive microcapsule, the temperature-sensitive microcapsule melts and releases an inorganic salt inhibitor. After the silicate gel undergoes inverse phase change, it gradually thins and its fluidity increases. The thinned gel and the inorganic salt inhibitor form a sol-inorganic salt composite inhibitor liquid system. The inorganic salt inhibitor will no longer react with silicate after thinning the silicate gel, and seeps into the high-temperature cracks to cooperate in flame retardancy. The unreacted sodium silicate in the silicate colloid can form a sodium silicate film with combustible substances to isolate oxygen; at the same time, the inorganic salt inhibitor can achieve the effect of moisturizing and oxygen isolation; the viscosity of the sol is larger than that of the solution, and it can also achieve the effect of water retention.

[0022] Beneficial effects

[0023] Compared with the prior art, the high-permeability temperature-sensitive inverse phase change gel for mining provided by the present invention, its preparation method and application have the following specific advantages:

[0024] The high-permeability temperature-sensitive inverse phase change gel for mining of the present invention is non-toxic and harmless, does not pollute the environment, has a wide source, a low and controllable price, and a simple and efficient manufacturing process. Sodium silicate is a water-soluble silicate, which can be used as an adhesive for cardboard, wood, and refractory materials, and is used in glass manufacturing to make the glass more fire-resistant, corrosion-resistant, etc. It can also be used to manufacture biodegradable environmental protection materials, and can react with acidic substances to form silicate gel. Silicic acid is the most commonly used inorganic gel for fire prevention and extinguishing in coal mines. Through microcapsule temperature-controlled release, the present invention retains the good plugging performance and water retention performance of the silicate gel, and at the same time can achieve a relatively large viscosity in the initial state of the gel material, so that it can stay at the high-temperature point; when the temperature of the high-temperature point in the fire area is too high, the microcapsule shell melts and releases an inorganic salt inhibitor to make the silicate gel undergo inverse phase change and thin, with enhanced fluidity. The thinned gel and the inorganic salt inhibitor jointly penetrate into the cracks that are difficult for the initial gel to penetrate to achieve three-dimensional fire extinguishing and gradient flame retardancy in the fire area. The microcapsules have a particle size of about dozens of micrometers, are small in size, can be evenly distributed in the gaps of coal blocks, have a wide coverage range, and can react with silicic acid at a smaller scale. Compared with the existing fire prevention and extinguishing gels, the inorganic sodium silicate gel provided by the present invention has a fast gel-forming speed, good fluidity at high temperature, a low price, and is safe and environmentally friendly. Description of the drawings

[0025] Figure 1 It is the schematic diagram of the inverse phase change of the high-permeability temperature-sensitive inverse phase change gel for mining in the embodiment of the present invention;

[0026] Figure 2 It is the manufacturing flow chart of the high-permeability temperature-sensitive inverse phase change gel for mining in the embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram showing the inverse phase change that occurs when a high-permeability temperature-sensitive inverse phase change gel for mining is added to a high-concentration salt solution in an embodiment of the present invention. Specific implementation scheme

[0028] The present invention will be described in detail below in conjunction with specific embodiments.

[0029] Since the process of changing from liquid to solid is called phase change in the field of coal fire prevention and extinguishment, the process that goes against this is called inverse phase change in this application. Specifically, as Figure 1 shown, when a high-permeability temperature-sensitive inverse phase change gel for mining is added to a high-concentration salt solution, an inverse phase change occurs. In the figure, 1 is a large amount of silicic acid gel, and it can be clearly seen in the figure that the silicic acid gel is diluted.

[0030] As Figure 2 shown, the present invention discloses a preparation method of a high-permeability temperature-sensitive inverse phase change gel for mining, and the steps are as follows:

[0031] S1. Heat the temperature-sensitive phase change material to a molten state;

[0032] S2. Gradually add an inorganic salt inhibitor to the molten temperature-sensitive phase change material in an inert gas atmosphere and stir evenly, so that the inorganic salt inhibitor particles are evenly distributed in the molten temperature-sensitive phase change material. During the stirring process, it is necessary to ensure that the temperature is 4 °C to 8 °C higher than the phase change temperature of the temperature-sensitive phase change material to ensure that the temperature-sensitive phase change material is always in a molten state; the inorganic salt inhibitor is in powder form, and the weight ratio of the temperature-sensitive phase change material to the added inorganic salt inhibitor is: 30 - 40 parts of the temperature-sensitive phase change material, 60 - 70 parts of the inorganic salt inhibitor, and the temperature-sensitive phase change material is a hydrophobic phase temperature-sensitive wall material;

[0033] S3. Add gelatin and span 80 to the mixed liquid, stir evenly, and then cool down to obtain a solid product, where the gelatin is 0.3 - 0.8 parts and the span 80 is 0.3 - 0.8 parts;

[0034] S4. Crush and grind the solid product into solid particles with a particle size of 40 - 60 mesh. The solid particles are temperature-sensitive microcapsules, and the temperature-sensitive microcapsules are structures in which the temperature-sensitive phase change material wraps the inorganic salt inhibitor. Since some temperature-sensitive microcapsules cannot ensure that the temperature-sensitive phase change material completely wraps the inorganic salt inhibitor during the preparation process, the crushed and ground solid particles are placed in cold water for 5 - 10 minutes to wash away the acidic salt powder that is not completely wrapped by the temperature-sensitive phase change material and the acidic salt powder leaked during crushing, and then dried for later use;

[0035] S5. Add the air-dried thermosensitive microcapsules into a sodium silicate solution. The mass ratio of the thermosensitive microcapsules to the sodium silicate solution is 1:5 to 1:8, and the mass concentration of the sodium silicate solution is 2% to 4%. Then, add an acidic substance into the sodium silicate solution to react with the sodium silicate to generate a gel. Through a metathesis reaction, using the principle of strong acid making weak acid, the sodium silicate forms a silicic acid gel, enabling the thermosensitive microcapsules to be evenly distributed in the silicic acid gel to form a highly permeable thermosensitive inverse phase change gel.

[0036] Example 1

[0037] For lignite, its self-heating critical temperature is about 65°C. When the coal body temperature is higher than 65°C, the lignite enters the rapid oxidation stage, and the coal temperature rising rate accelerates. Traditional gels cannot penetrate deep into the coal body to rapidly reduce the coal temperature. Therefore, a phase change gel with a phase change temperature of about 75°C needs to be prepared to prevent the rapid oxidation of lignite.

[0038] A kind of high-permeability thermosensitive inverse phase change gel for mine use. Weigh 20 parts of polyethylene glycol 20000 and 20 parts of pentaerythritol stearate, mix them in a beaker, and place the beaker in a water bath at 75°C to heat until it reaches the molten state and stir evenly to obtain a wall material mixed liquid. Under the environment of nitrogen, gradually add 60 parts of 100-mesh magnesium chloride powder to the wall material mixed liquid and keep stirring. After stirring evenly, add 0.6 part of gelatin and span 80 to the mixed liquid, stir evenly, and then cool down to obtain a solid product. Crush and grind the prepared solid product to obtain solid microcapsules with a particle size of 50 mesh. Add the prepared microcapsules into 500 parts of a sodium silicate solution with a mass fraction of 3% and react with 200 parts of a sodium bicarbonate solution with a mass fraction of 8% to generate a high-permeability thermosensitive inverse phase change gel;

[0039] Transport the above-mentioned high-permeability thermosensitive inverse phase change gel to the gob and easily self-igniting coal seams through pipelines, covering all the remaining coal and staying at the high-temperature points. If the temperature of the high-temperature points in the coal seam rises to 73°C, the microcapsule wall shell melts, releasing the inhibitor salt powder to react with the silicic acid gel, prompting the gel to undergo an inverse phase change, resulting in the precipitation of silicic acid, making the viscous silicic acid gel thinner at high temperatures, increasing the permeability of the gel at high temperatures. The thinned gel can penetrate into the interior of the high-temperature remaining coal and form a secondary synergistic inhibition effect together with the inhibitor salt solution.

[0040] Example 2

[0041] For bituminous coal, its self-heating critical temperature is about 70°C. When the coal body temperature is higher than 70°C, the bituminous coal enters the rapid oxidation stage, and the coal temperature rising rate accelerates. Traditional gels cannot penetrate deep into the coal body to rapidly reduce the coal temperature. Therefore, a phase change gel with a phase change temperature of about 90°C needs to be prepared to prevent the rapid oxidation of lignite.

[0042] A kind of mine-used highly permeable temperature-sensitive inverse phase change gel. Weigh 54 parts of 70# chlorinated paraffin and 4 parts of 52# chlorinated paraffin, mix them in a beaker, and place the beaker in a water bath at 90 °C to heat until it reaches the molten state and stir evenly to obtain the wall material mixed liquid. Under the environment of nitrogen, add 60 parts of 100-mesh ammonium dihydrogen phosphate powder to the wall material mixed liquid gradually and in portions while continuously stirring. After stirring evenly, add 0.8 part of gelatin and span 80 to the mixed liquid respectively, stir evenly, and then cool down to obtain a solid product. Crush and grind the prepared solid product to obtain solid microcapsules with a particle size of 50 mesh. Add the prepared microcapsules to 500 parts of a sodium silicate solution with a mass fraction of 3% and react with 200 parts of an acetic acid solution with a mass fraction of 6% to generate a highly permeable temperature-sensitive inverse phase change gel; Transport the above-mentioned highly permeable temperature-sensitive inverse phase change gel to the gob area and the easily self-igniting coal seam through a pipeline, cover all the residual coal and stay at the high-temperature point. If the temperature of the high-temperature point in the coal seam rises to 87 °C, the microcapsule wall shell melts, releasing the inhibitor salt powder to react with silicic acid to promote the precipitation of silicic acid, so that the viscous silicic acid gel gradually thins during the inverse phase change at high temperature, increasing the permeability of the gel at high temperature. The thinned gel can penetrate into the interior of the high-temperature residual coal and form a secondary synergistic inhibition effect together with the inhibitor salt solution.

[0043] Example 3

[0044] For anthracite, its self-heating critical temperature is about 85 °C. When the temperature of the coal body is higher than 85 °C, anthracite enters the rapid oxidation stage, and the coal temperature rising rate accelerates. Traditional gels cannot penetrate deep into the deep part of the coal body to quickly reduce the coal temperature. Therefore, a phase change gel with a phase change temperature of about 100 °C needs to be prepared to prevent the rapid oxidation of lignite. A kind of mine-used highly permeable temperature-sensitive inverse phase change gel. Weigh 56 parts of 70# chlorinated paraffin and 2 parts of 52# chlorinated paraffin, mix them in a beaker, and place the beaker in a water bath at 100 °C to heat until it reaches the molten state and stir evenly to obtain the wall material mixed liquid. Under the environment of nitrogen, add 60 parts of 100-mesh sodium chloride powder to the wall material mixed liquid gradually and in portions while continuously stirring. After stirring evenly, add 0.5 part of gelatin and span 80 to the mixed liquid respectively, stir evenly, and then cool down to obtain a solid product. Crush and grind the prepared solid product to obtain solid microcapsules with a particle size of 50 mesh. Add the prepared microcapsules to 500 parts of a sodium silicate solution with a mass fraction of 3% and react with 200 parts of a ammonium bicarbonate solution with a mass fraction of 5% to generate a highly permeable temperature-sensitive inverse phase change gel;

[0045] The above-mentioned highly permeable thermosensitive inverse phase change gel is transported to the goaf and easily self-igniting coal seams through pipelines, covering all the remaining coal and staying at the high-temperature points. If the high-temperature points of the coal seams rise to 97 °C, the microcapsule wall shells melt, releasing inhibitor salt powders that react with silicic acid to promote the precipitation of silicic acid, causing the viscous silicic acid gel to gradually thin during inverse phase change at high temperatures, increasing the permeability of the gel at high temperatures. The thinned gel can penetrate into the interior of the high-temperature remaining coal and form a secondary synergistic inhibition effect together with the inhibitor salt solution.

Claims

1. A method for preparing a high permeability temperature-sensitive reverse phase change gel for mining, characterized in that: Here are the steps: S1, heating the temperature-sensitive phase change material to a molten state; S2. In an inert gas atmosphere, add inorganic salt inhibitor powder to the molten temperature-sensitive phase change material in small amounts and stir evenly, so that the inorganic salt inhibitor powder particles are evenly distributed in the molten temperature-sensitive phase change material. The stirring process needs to ensure that the heating temperature is 4°C to 8°C higher than the phase change temperature of the temperature-sensitive phase change material to ensure that the temperature-sensitive phase change material is always in a molten state; the weight ratio of the temperature-sensitive phase change material to the added inorganic salt inhibitor is: 30 to 40 parts of the temperature-sensitive phase change material and 60 to 70 parts of the inorganic salt inhibitor. The temperature-sensitive phase change material is a hydrophobic temperature-sensitive wall material and includes a mixture of one or more of 70# chlorinated paraffin, 52# chlorinated paraffin, polyethylene glycol, polyvinyl chloride, ethyl cellulose, and pentaerythritol stearate; the temperature-sensitive phase change material is heated to 75 to 90°C at the high temperature point of the coal seam to reach the phase change temperature and melt, and the inorganic salt inhibitor is one or more of magnesium chloride, sodium chloride, and diammonium phosphate; S3, adding gelatin and Span 80 to the molten state temperature-sensitive phase change material of the mixed inorganic salt inhibitor powder, stirring evenly, and cooling to obtain a solid product, wherein the gelatin is 0.3-0.8 parts, and the Span 80 is 0.3-0.8 parts; S4, crushing and grinding the solid product into solid particles with a particle size of 40-60 mesh, the solid particles are thermosensitive microcapsules, and the thermosensitive microcapsules are structures in which the thermosensitive phase change material wraps the inorganic salt inhibitor. Since the preparation process of some thermosensitive microcapsules cannot ensure that the thermosensitive phase change material completely wraps the inorganic salt inhibitor, the thermosensitive microcapsules are placed in cold water for 5-10 minutes to wash away the inorganic salt inhibitor powder that is not completely wrapped by the thermosensitive phase change material and the inorganic salt inhibitor powder leaked during crushing, and then dried for use; S5. Add the air-dried thermosensitive microcapsules to the sodium silicate solution and mix them evenly. The mass ratio of the thermosensitive microcapsules to the sodium silicate solution is 1:5-1:8, and the mass concentration of the sodium silicate solution is 2%-4%. Then, add an acidic substance to the sodium silicate solution to react with the sodium silicate to produce a gel, and then through a double decomposition reaction, use the principle of strong acid to produce weak acid to make the sodium silicate form a silicic acid gel, so that the thermosensitive microcapsules are evenly distributed in the silicic acid gel to form a high-permeability thermosensitive reverse phase change gel. The acidic substance is sodium bicarbonate, acetic acid, hydrochloric acid, ammonium chloride or ammonium sulfate.

2. The method for preparing a high permeability temperature-sensitive reverse phase change gel for mining according to claim 1, characterized in that: The melting point of the temperature-sensitive phase change material is determined according to the self-heating critical temperature of the coal from the slow oxidation stage to the rapid oxidation and heating stage. The melting point of lignite is less than 75°C, that of bituminous coal is less than 80°C, and that of anthracite is less than 90°C.

3. The method for preparing a high permeability temperature-sensitive reverse phase change gel for mining according to claim 1, characterized in that: Inert gases include nitrogen, helium or carbon dioxide.

4. The method for preparing a high permeability temperature-sensitive reverse phase change gel for mining according to claim 1, characterized in that: The inorganic salt inhibitor added to the temperature-sensitive phase change material is in a particle structure, and the particle size of the inorganic salt inhibitor is 80-120 meshes.

5. The method for preparing a high permeability temperature-sensitive reverse phase change gel for mining according to claim 1, characterized in that: The modulus of sodium silicate is 2~3.

6. The method for preparing a high permeability temperature-sensitive reverse phase change gel for mining according to claim 1, characterized in that: When the coal seam inclination is greater than 25 degrees, a thickener needs to be added to the sodium silicate solution, and the thickener is sodium polyacrylate or polyacrylamide.

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