Two-component inorganic foaming grouting material as well as preparation method and application thereof

Abstract

The invention provides a two-component inorganic foaming grouting material which comprises a material A and a material B. The material A is composed of carbonate, sodium silicate and the like, and the material B contains boric acid, phosphoric acid and the like. According to the material, calcium carbonate or magnesium carbonate reacts with acid to generate carbon dioxide to achieve foaming, and through the synergistic effect of the dispersing agent, the thickening agent and the foam stabilizer and a double-acid system formed by boric acid and phosphoric acid, the viscosity of the system is accurately regulated and controlled, the foam stability is ensured, and the compressive strength and the flame retardant property are improved. Experimental results show that the compressive strength exceeds 12MPa, the foam expansion is higher than 7 times, the volume shrinkage is lower than 6%, and the initial setting time is flexibly adjusted within a certain range. The material has excellent flame retardance and antistatic property, can fully permeate into micropores and complex rock stratum cracks, improves the repair effect on hidden structures, has wide application prospects in the field of underground coal mine filling and reinforcement, and realizes safety, controllability and green low carbon.

Description

Technical Field

[0001] The present invention belongs to the field of grouting filling reinforcement, and in particular relates to a two-component inorganic foaming grouting material and a preparation method and application thereof. The material has excellent flame retardant properties, high foaming multiple, outstanding mechanical properties and antistatic properties. Background Art

[0002] During coal mining operations, serious problems such as gas accumulation and spontaneous combustion often occur in areas such as empty lanes, upper corners, high-risk areas, and spaces behind coal mines. Filling foam materials are a key means of addressing these issues. Currently, the main filling foam materials include cement-based inorganic foams and organic foams such as polyurethane and phenolic resins. These materials play a vital role in coal mine safety management.

[0003] Polymer grouting materials are a key technology for filling mine tunnels, preventing air leaks, and suppressing coal spontaneous combustion. Currently, polymer air leakage plugging materials are primarily categorized as organic and organic-inorganic composites. Polymer cured foams are a common material. Due to their advantages, such as controllable reaction time, high bonding strength, and excellent permeability and diffusion, polymer foams have been widely used in coal mine grouting both domestically and internationally. Common types include polyurethane foam, phenolic foam, and urea-formaldehyde foam, and they play a vital role in coal mine grouting projects. However, polymer grouting foams also have drawbacks. For example, polyurethane foam generates high heat during foaming, has poor thermal stability, is flammable, and releases toxic gases during combustion; phenolic foams are prone to surface pulverization, have highly toxic raw materials, and are inherently brittle; and urea-formaldehyde foams suffer from poor water resistance, aging, and high formaldehyde emissions. Furthermore, organic air leakage plugging materials generally suffer from high cost and poor flame retardancy. To address these issues, the current main solution is to add an appropriate amount of inorganic materials to the polymer matrix to combine the properties of both organic and inorganic materials. Given the abundant availability, low cost, non-toxicity, and flame retardancy of inorganic materials, polymer foam grouting materials are often mixed with one or more inorganic materials such as yellow mud, cement, clay, water glass, sand, bentonite, diatomaceous earth, silica, fly ash, and gravel, along with certain additives, to form a foamed polymer-based organic-inorganic composite grouting material, which has been widely used in coal mine reinforcement and filling. Although the addition of inorganic materials can reduce the cost of organic materials and impart certain properties to the materials, the high viscosity of the inorganic materials during the mixed foaming process to prepare the air leakage plugging material can hinder the full foaming of the foam, affecting the grouting efficiency.

[0004] Cement-based inorganic foamed grouting materials play a vital role in coal mine safety management. Their low cost and readily available raw materials have led to their widespread use in many coal mines. Furthermore, cement-based inorganic foamed grouting materials exhibit excellent fire resistance and corrosion resistance, allowing them to adapt to the complex chemical environment of underground coal mines to a certain extent, further enhancing their practical application in the coal mining sector. However, these materials also have some significant drawbacks. Firstly, they have a long curing time, which can require a long wait for them to fully cure and function in practical applications. This can delay remediation efforts in emergency situations requiring rapid repair and reinforcement. Secondly, their low early strength makes them unable to withstand the significant pressure and loads during the initial curing phase, severely impacting their support for the surrounding rock formations and, in turn, reducing their effectiveness in managing gas accumulation and coal seam spontaneous combustion. Furthermore, these materials are prone to shrinkage cracks, which develop internally due to volumetric shrinkage during the curing process. These cracks not only reduce the overall strength and density of the material, but may also provide new infiltration paths for gas, increasing the risk of gas leakage. At the same time, they also weaken the material's reinforcement effect on the coal seam, making it easier for the coal to come into contact with oxygen in the air, thereby increasing the possibility of spontaneous combustion of the coal seam.

[0005] In light of the challenges of existing organic and cement-based inorganic grouting materials in terms of permeability, foam stability, mechanical properties, and flame retardancy, the present invention aims to provide a two-component inorganic foaming grouting material. This material can fully penetrate micropores and fissures in complex rock formations, significantly improving the repair of fine crack structures. It also optimizes the grouting material's compressive strength, flame retardancy, volume stability, and curing time, achieving safe, controllable, and green, low-carbon filling and reinforcement in underground coal mines, demonstrating broad application prospects. Summary of the Invention

[0006] The purpose of the present invention is to provide a two-component inorganic foaming grouting material and its preparation method and application, using calcium carbonate or magnesium carbonate as a foaming agent, and through the synergistic compounding of a dispersant and a thickener, accurately controlling the viscosity of the system, thereby achieving excellent dispersion stability of calcium carbonate or magnesium carbonate particles and ensuring the stability of the foam before solidification; at the same time, using a double acid system composed of boric acid and phosphoric acid, the material achieves significant improvements in compressive strength, flame retardant properties, volume shrinkage, and flame retardant and antistatic effects.

[0007] The present invention provides a two-component inorganic foaming grouting material, comprising material A and material B in a mass ratio of 1:3, wherein:

[0008] Material A includes the following raw materials in parts by weight: 20-45 parts of carbonate, 15-40 parts of sodium silicate, 3-15 parts of dispersant, 2-6 parts of thickener, 3-8 parts of foam stabilizer, 1-10 parts of acid scavenger, 1-10 parts of auxiliary agent, and 40-100 parts of water.

[0009] Material B comprises the following raw materials in parts by weight: 5-15 parts of boric acid, 1-5 parts of phosphoric acid, 0.1-2 parts of a complexing agent, and 20-50 parts of water.

[0010] Preferably, the carbonate is at least one of calcium carbonate and magnesium carbonate, and the average particle size of the calcium carbonate or magnesium carbonate is 0.1-10 μm, and more preferably the average particle size of the calcium carbonate or magnesium carbonate is 0.1-1 μm; the modulus of the sodium silicate is 1.5-2.5. After material A and material B are mixed, the carbonate in the material A component reacts chemically with the acid in the material B component to generate carbon dioxide. The thickener adjusts the viscosity of the mixed liquid to a moderate level to ensure the stability of the foam before solidification. Sodium silicate solidifies in an acidic environment to form a solidified foam state. A slow acid-removing substance is added to the material A component to neutralize the remaining acid after the reaction and generate a stable phosphate precipitate, thereby optimizing the performance of the grouting body and long-term safety.

[0011] In the present invention, the boric acid and phosphoric acid diacid system has significant advantages over single acid in coal mine grouting materials: (1) borate ions generated by boric acid hydrolysis react with sodium silicate to form borosilicate gel containing a Si-OB network structure, while phosphoric acid and sodium silicate generate silica gel (SiO2·nH2O). The two composite fill the pores, forming a denser three-dimensional structure, which can improve compressive strength and crack resistance. (2) In terms of flame retardancy, boron and phosphorus form a dense carbon-glass layer through a synergistic flame retardant mechanism, improving the flame retardant properties of the filler; at high temperatures, inorganic phosphate dehydrates to form a phosphorus-rich glassy substance, and borate decomposes to produce glassy boron oxide (B2O3), forming a dense protective layer on the filler surface, isolating oxygen and heat, thereby playing a flame retardant role. (3) The boric acid and phosphoric acid diacid system can achieve staged curing and improve curing efficiency. Phosphoric acid reacts quickly with sodium silicate to form silica gel, providing initial strength, achieving rapid plugging, and shortening the initial setting time. Boric acid generates borosilicate gel more slowly, which can extend the final setting time and ensure that the slurry fully penetrates the cracks. It achieves precise control of the initial and final setting times, reduces the shrinkage rate of curing, and has both rapid plugging and deep penetration capabilities. It meets the grouting needs and environmental adaptability for flexible adaptation to emergency plugging, and takes into account efficient construction and long-term stability. In the mass distribution of the diacid system, the mass part of boric acid is selected to be greater than the mass part of phosphoric acid to avoid insufficient penetration caused by too high a phosphoric acid content, which leads to too fast curing, or insufficient initial strength caused by too high a boric acid content, which leads to too slow reaction. A combination of 5-15 parts of boric acid and 1-5 parts of phosphoric acid is further preferred.

[0012] Preferably, the dispersant is sodium dodecylbenzene sulfonate and sodium polyacrylate, wherein the mass ratio of sodium dodecylbenzene sulfonate to sodium polyacrylate is 1:0.5-2. Sodium dodecylbenzene sulfonate is an anionic surfactant. The hydrophilic sulfonic acid group in its molecule can ionize a large number of negative ions in water, which can be adsorbed on the surface of calcium carbonate particles, making the surface of calcium carbonate particles negatively charged. Similarly, the carboxylate ions dissociated from sodium polyacrylate in water react with the calcium carbonate on the particle surface. 2 / Mg 2+ The sodium polyacrylate binds to form a strong adsorption layer and can also adsorb to the surface of calcium carbonate particles, imparting a negative charge to the particle surface. Because like charges repel each other, electrostatic repulsion is generated between calcium carbonate or magnesium carbonate particles, hindering their proximity and agglomeration, thereby improving their dispersion in water. Furthermore, sodium polyacrylate molecular chains have a certain length and flexibility. When sodium polyacrylate adsorbs on the surface of calcium carbonate or magnesium carbonate particles, it forms a steric hindrance layer, further increasing the steric hindrance between the particles, making it difficult for the particles to agglomerate and improving the dispersion stability of calcium carbonate or magnesium carbonate in water.

[0013] Preferably, the molecular weight of the polyacrylamide is 5 million to 15 million Daltons.

[0014] Preferably, the thickening agent is xanthan gum and polyacrylamide, wherein the mass ratio of xanthan gum to polyacrylamide is 1:0.2-0.5. Xanthan gum is a high molecular weight polysaccharide, and contains a large amount of hydrophilic groups such as hydroxyl and carboxyl groups on the molecular chain. It can form hydrogen bonds with water molecules and form a colloidal solution with a three-dimensional network structure after dissolution, thereby increasing the viscosity of the system. Calcium carbonate or magnesium carbonate particles are wrapped in a viscous solution, and their movement is restricted, making it difficult to collide with each other and reunite, thereby playing a role in suspension stabilization. Polyacrylamide belongs to a linear high molecular weight polymer, and the three-dimensional network of xanthan gum and the linear chain of PAM intersperse to form a denser composite gel structure, further improving the viscosity of the solution, further suppressing particle precipitation, playing the role of stabilizing the system, and being very conducive to the dispersion effect of calcium carbonate or magnesium carbonate in water.

[0015] While the foaming agent in foamed grouting materials can effectively foam under conditions such as stirring and blowing, the resulting foam is unstable and difficult to maintain. To prolong the stability of the foam, a small amount of foam stabilizer is often added to the foaming agent solution to modify the surface physical and chemical properties of the bubble film, thereby improving foam stability. Among these, appropriately increasing the slurry viscosity is a common method for improving foam stability. If the slurry viscosity is too low, it is not conducive to sealing the internal gas, resulting in a low bubble nucleation rate. Excessively high slurry viscosity inhibits bubble nucleation and growth, affecting the overall expansion of the material and hindering the uniform dispersion of the foaming agent in the slurry. The foam stabilizer used is a combination of polyethylene oxide and a stearate. Preferably, the stearate is one or more of calcium stearate, magnesium stearate, or zinc stearate. The mass ratio of polyethylene oxide to stearate is 4:0.5-2. As a foam stabilizer, stearate can improve the viscosity and strength of bubbles, making them uniform, dense and stable, and preventing large-scale rupture of bubbles in the filling material when they come into contact with air or when foams collide with each other; and polyethylene oxide (PEO polymer) contains a large amount of -COC structure, which can significantly increase the viscosity of the foaming liquid, thereby forming a viscous and stable sol solution.

[0016] In coal mine grouting materials, if there is excessive phosphoric acid in the system, the strongly acidic environment (too low pH) will inhibit the hydrolysis-polycondensation reaction of sodium silicate, resulting in hindered gel network formation, manifested as delayed curing, uneven structure, and internal pore formation. After grouting, residual phosphoric acid will continue to destroy the silica skeleton, reducing mechanical strength and durability. At the same time, soluble phosphates will precipitate or react with the surrounding rock, causing chemical corrosion, dissolution holes, and groundwater contamination, threatening tunnel stability. By precisely controlling the ratio and adding acid scavengers, excess phosphoric acid can be neutralized to form a stable phosphate precipitate, thereby optimizing the performance and long-term safety of the grouting body.

[0017] Preferably, the acid scavenger is one or both of polyaluminium chloride and polyferric sulfate. 3 + ions, polyferric sulfate dissolves in water to form Fe 3+ Ions, Al ions or Fe ions can react with phosphate ions to form insoluble aluminum phosphate precipitates or ferric sulfate precipitates, thereby removing excess phosphoric acid from the slurry and achieving the purpose of deacidification.

[0018] Preferably, the complexing agent is at least one of ethylenediaminetetraacetic acid and its salts, citric acid and its salts or tartaric acid and its salts. Adding a complexing agent to the second material can reduce the precipitation or stratification caused by metal ions such as calcium and magnesium in the water. The complexing agent reacts with metal ions (such as Ca 2+ Mg 2+) to form a stable complex, preventing it from combining with phosphate / borate to form precipitation, and achieving a uniform and stable solution system by inhibiting the interference of metal ions.

[0019] Furthermore, the auxiliary agent of the material A includes at least one of a pH regulator, an enhancer, and an antifreeze agent.

[0020] The present invention also provides a method for preparing a two-component inorganic foaming grouting material, which specifically comprises the following steps:

[0021] S1: weighing the raw materials in material A according to the stoichiometric amount, and stirring and mixing the raw materials to obtain material A;

[0022] S2: Weigh the raw materials in material B according to the stoichiometric amount, and stir and mix the raw materials to obtain material B.

[0023] Preferably, the stirring and mixing temperature in steps S1 and S2 is 20-30° C., and the mixing time is 10-50 min.

[0024] The present invention also provides an application of a two-component inorganic foaming grouting material in a coal mine, comprising the following steps: using a grouting pump to add material A and material B in a mass ratio of 1:3 to a grouting system, and using a grouting machine to perform solidification and filling.

[0025] The advantages or beneficial effects of the two-component inorganic foaming grouting material of the present invention include at least:

[0026] The two-component inorganic foaming grouting material of the present invention is a highly fluid slurry that can fully penetrate micropores and complex rock cracks, greatly improving the repair effect on hidden structures. Through the synergistic effect of compound dispersants and thickeners, the viscosity of the system is precisely controlled to ensure uniform suspension of particles and bubble stability, making the slurry excellent in fluidity during pumping. The innovatively introduced boric acid-phosphoric acid diacid system simultaneously optimizes the compressive strength, flame retardancy, volume stability and curing time of the grouting material through a staged reaction mechanism (phosphoric acid rapid nucleation, boric acid slow setting and strengthening), achieving safe, controllable and green low-carbon filling and reinforcement of coal mines, and has broad application prospects. DETAILED DESCRIPTION

[0027] To more clearly illustrate the objectives, technical solutions, and advantages of the present invention, the technical solutions of the present invention will be described in detail below through specific embodiments. It should be noted that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. The actual scope of protection of the present invention shall be based on the definition of the claims.

[0028] Unless otherwise specified, the materials and reagents used in the following examples and comparative examples are commercially available. The amounts of the components in the following examples are 1 g per part by weight unless otherwise specified.

[0029] 1. Prepare two-component inorganic foaming grouting material.

[0030] The present invention relates to a method for preparing a two-component inorganic foaming grouting material, comprising material A and material B in a mass ratio of 1:3, specifically comprising the following steps:

[0031] S1: Preparation method of material A: According to the composition and content of material A in Table 1, use a high-speed stirring barrel to stir and mix at 25°C and 800 r / min for 35 minutes to obtain material A.

[0032] S2: Preparation method of material B: According to the composition and content of material B in Table 1, use a high-speed stirring barrel to stir and mix at 25°C and 500r / min for 15 minutes to obtain material B.

[0033] Table 1: The mass parts (g) of each component in Examples 1-4 are as follows.

[0034]

[0035] Example 5

[0036] The difference from Example 2 is that 0.1 μm magnesium carbonate is used, and other conditions are the same as those in Example 2.

[0037] Example 6

[0038] The difference from Example 2 is that 0.5 μm magnesium carbonate is used, and other conditions are the same as those in Example 2.

[0039] Example 7

[0040] The difference from Example 2 is that 1 μm magnesium carbonate is used, and other conditions are the same as those in Example 2.

[0041] Example 8

[0042] The difference from Example 2 is that 10 μm magnesium carbonate is used, and other conditions are the same as those in Example 2.

[0043] Table 2: The mass parts (g) of each component in Comparative Examples 1-8 are as follows.

[0044]

[0045]

[0046] 2. Performance evaluation:

[0047] The two-component inorganic foaming grouting material prepared in the embodiment and the comparative example is applied in the coal mine goaf, comprising the following steps: using a grouting pump to add material A and material B in a mass ratio of 1:3 to the grouting system, and using a grouting machine to solidify and fill.

[0048] 1. Gel time test

[0049] The gel time of plugging materials is crucial for grouting plugging construction. Reasonable gel time allows the slurry to fully diffuse in the formation. If the gel time is too long, the slurry is prone to leakage in the cracks and pores, making it difficult to effectively seal the cracks; if the gel time is too short, the slurry is difficult to fully diffuse in the crack network within the coal seam, affecting the grouting plugging effect on the coal body. Therefore, the gel time of the material should be reasonably controlled according to the actual construction conditions.

[0050] The initial setting time and final setting time of the grouting material are tested in accordance with the national standard GB8076-2008 "Concrete Admixtures".

[0051] 2. Material expansion rate test

[0052] Plugging materials with good expansion properties can produce a certain volume expansion during the solidification process, allowing them to fit tightly with the surface of the coal body cracks and fully fill every corner of the cracks, thereby achieving full sealing of the coal body cracks. On the contrary, if the plugging material shrinks in volume after solidification, the part that was originally tightly combined with the surface of the coal body cracks will produce gaps due to shrinkage, causing the material to separate from the surface of the coal body cracks. In this way, the cracks that were originally blocked will form leakage channels again, affecting the sealing effect of the coal body, and may have adverse effects on many aspects such as the safety of the coal mine. Therefore, in order to ensure that the coal body cracks can be effectively and durably blocked, the plugging material must have a certain volume expansion performance during use and must have a very low volume expansion rate after solidification.

[0053] The volume shrinkage rate of grouting materials is tested in accordance with GB / T 13477.19-2019 "Test Methods for Building Sealing Materials".

[0054] 3. Material mechanical strength test

[0055] Grouting plugging materials must have sufficient mechanical strength to provide effective support stress for the coal body, prevent further expansion of coal cracks around the borehole, and avoid instability and damage of the coal body, thereby achieving a long-term plugging effect.

[0056] Referring to the requirements of AQ / T 1089-2020 standard, first pour the prepared material slurry into a 10cm×10cm×10cm mold, demold it after 24 hours, and place the test sample in an environment of 20℃ and 50% relative humidity for further curing for 7 days. The compressive strength of the material at 7 days is tested. The average value of 5 test samples is selected for each group of experimental test results.

[0057] 4. Foaming multiple

[0058] During coal mine filling, a good expansion ratio offers numerous advantages for grouting materials, including rapid filling, material savings and cost savings, and improved construction efficiency. It also effectively blocks gas, prevents coal instability, and enhances project safety. However, if the expansion ratio is too low, a large amount of material is required to fill the space, leading to increased costs, reduced construction efficiency, and suboptimal sealing and support effects. If the expansion ratio is too high, the material may experience shrinkage and cracking due to insufficient stability, compromising filling effectiveness and coal stability, and even requiring additional reinforcement measures, which in turn increases construction difficulty and cost. The expansion ratio is tested in accordance with the JC / T266-2011 standard for "Foamed Concrete."

[0059] Table 3 Grouting material properties of different embodiments and control examples

[0060]

[0061]

[0062] According to the test results in Table 3, the embodiments of the present invention use calcium carbonate or magnesium carbonate as a foaming agent, and through the synergistic compounding of a dispersant, a thickener and a foam stabilizer, the viscosity of the system is precisely controlled, thereby achieving excellent dispersion stability of the calcium carbonate or magnesium carbonate particles and ensuring that the foam remains stable before solidification. At the same time, the two-component inorganic foaming grouting material prepared by using a double acid system composed of boric acid and phosphoric acid exhibits excellent performance in coal mine filling: the compressive strength exceeds 12MPa, which can effectively improve the overall safety of soft and broken coal rock formations; the foaming multiple is higher than 7, and the initial setting time can be flexibly adjusted within a certain range according to the foaming multiple. In addition, the volume shrinkage rate of the grouting material is less than 6%, and the volume change after solidification is extremely small. It can fill the pores and cracks of the coal rock mass more tightly, reduce the pores caused by material shrinkage, and avoid causing geological disasters and safety hazards.

[0063] By comparing the results of Example 2 with those of Examples 5-8, it can be found that the average particle size of the calcium carbonate or magnesium carbonate particles has a significant effect on the foaming multiple of the grouting material. When the average particle size of the particles decreases within a certain range, its specific surface area increases accordingly. This allows the particles to more fully contact with phosphoric acid and undergo a chemical reaction, accelerating the generation of carbon dioxide gas, forming more foam, and thus increasing the foaming multiple. The increase in the foaming multiple changes the gas-liquid ratio of the system, resulting in an extension of the stability time of the foam, and the initial setting time of the grouting material is also extended. In addition, since the volume of the foaming material is more stable during the curing process and the volume shrinkage rate is reduced, the volume change of the grouting material after curing is reduced, and the pores and cracks of the coal rock mass can be more effectively filled, the pores caused by material shrinkage are reduced, the risk of gas leakage is reduced, and the safety of the coal mine is improved.

[0064] From the comparison of Comparative Examples 1-8 with Example 2, it can be seen that the dispersant, thickener and foam stabilizer are not compounded, but only a single dispersant, thickener and foam stabilizer is used, which leads to a decrease in the dispersibility of calcium carbonate or magnesium carbonate in the water system, a decrease in the foaming multiple, and a relatively high relative content and concentration of water glass in the slurry, thereby accelerating the coagulation and hardening process of the slurry, resulting in a shortening of the initial setting time and the final setting time; at the same time, the grouting material cannot tightly fill the pores and cracks in the coal rock mass, thereby reducing the mechanical strength of the coal mine filling and increasing the volume shrinkage rate, which significantly affects the performance of the grouting material.

[0065] By comparing Comparative Examples 1-8 and Example 2, it can be found that if the compounding scheme of dispersant, thickener and foam stabilizer is not adopted, and only single component is used, the dispersibility variation of calcium carbonate or magnesium carbonate in water system will be caused. Dispersibility decline makes calcium carbonate or magnesium carbonate insufficient to react with phosphoric acid, and the efficiency of generating carbon dioxide foam is reduced, and then causes foaming multiple to reduce. Due to the reduction of foaming multiple, the relative content and concentration of water glass in the slurry are relatively improved, and its content is high and can accelerate the coagulation and hardening reaction of slurry, so that the initial setting time is shortened, and the construction operation time is limited, and the risk of pipeline blockage increases. Meanwhile, due to the low foaming multiple and insufficient slurry filling performance, the pores and cracks of coal rock mass cannot be filled tightly by grouting material, and the pore filling insufficiently reduces the mechanical support capacity of coal rock mass, so that the mechanical strength of coal mine filling is reduced. In addition, due to the low foaming multiple and poor volume stability of the slurry, the volume shrinkage rate of the grouting material increases during the solidification process. The pores generated by the material shrinkage will weaken the integrity of the coal rock mass, thereby significantly affecting the overall performance of the grouting material and failing to effectively achieve the purpose of improving the safety and stability of coal mines.

[0066] 3. Flame retardancy and antistatic properties of grouting materials

[0067] The flame retardancy and antistatic properties of the product prepared in Example 2 were tested according to MT / T113-1995 "General Test Methods and Judgment Rules for Flame Retardancy and Antistatic Properties of Polymer Products for Use in Coal Mines". The test results are as follows:

[0068] Table 5 Flame retardant and antistatic test report of products used in underground coal mines

[0069]

[0070] The above test results show that the flame retardant and antistatic safety test report of the grouting material product using embodiment 2 shows that all test items are qualified. In the alcohol burner and alcohol lamp combustion test, the flaming burning time and the flameless burning time of the material are all far below the maximum value of the technical requirements, indicating that it possesses excellent flame retardant properties, can quickly extinguish flames, and prevent the spread of fire. The surface resistance test result also shows that the upper and lower surface resistances of the material are all lower than the technical requirements, have good antistatic properties, and can effectively reduce the risk of static discharge causing fire or explosion. This fully illustrates that when the polymer product is used in coal mines, reliable safety protection can be provided for operating environment, and meets the strict requirements of coal mines for flame retardant and antistatic properties of materials.

[0071] The above embodiments are merely examples provided to illustrate the present invention and are not intended to limit the possible implementations of the present invention. Based on the disclosure of the present invention, those skilled in the relevant art may make various modifications and adjustments. It is neither possible nor necessary to enumerate all possible implementations. Any modification, equivalent substitution, or improvement made within the basic principles and scope of the present invention shall be deemed to fall within the scope of protection of the present invention.

Claims

1. A two-component inorganic foaming grouting material, characterized in that: It includes material A and material B in a mass ratio of 1:3, wherein: Material A comprises the following raw materials in parts by weight: 20-45 parts of carbonate, 15-40 parts of sodium silicate, 3-15 parts of dispersant, 2-6 parts of thickener, 3-8 parts of foam stabilizer, 1-10 parts of acid scavenger, 1-10 parts of auxiliary agent, and 40-100 parts of water; Material B comprises the following raw materials in parts by weight: 5-15 parts of boric acid, 1-5 parts of phosphoric acid, 0.1-2 parts of a complexing agent, and 20-50 parts of water; The dispersant is sodium dodecylbenzenesulfonate and sodium polyacrylate, wherein the mass ratio of sodium dodecylbenzenesulfonate to sodium polyacrylate is 1:0.5-2; The thickener is xanthan gum and polyacrylamide, wherein the mass ratio of xanthan gum to polyacrylamide is 1:0.2-0.5; The foam stabilizer is polyethylene oxide and stearate, wherein the mass ratio of polyethylene oxide to stearate is 4:0.5-2.

2. A two-component inorganic foaming grouting material according to claim 1, characterized in that: The carbonate is at least one of calcium carbonate and magnesium carbonate; the average particle size of the calcium carbonate or magnesium carbonate is 0.1-10 μm.

3. A two-component inorganic foaming grouting material according to claim 1, characterized in that: The stearate is one or more of calcium stearate, magnesium stearate, and zinc stearate.

4. A two-component inorganic foaming grouting material according to any one of claims 1 to 3, characterized in that: The modulus of the sodium silicate is 1.5 to 2.5; the molecular weight of the polyacrylamide is 5 million to 15 million Daltons.

5. A two-component inorganic foaming grouting material according to any one of claims 1 to 3, characterized in that: The acid scavenger is one or both of polyaluminium chloride and polyferric sulfate.

6. A two-component inorganic foaming grouting material according to any one of claims 1 to 3, characterized in that: The auxiliary agent of the material A includes at least one of a pH regulator, an enhancer, and an antifreeze agent.

7. A two-component inorganic foaming grouting material according to any one of claims 1 to 3, characterized in that: The complexing agent of the second material is at least one of ethylenediaminetetraacetic acid and its salts, citric acid and its salts, or tartaric acid and its salts.

8. A method for preparing a two-component inorganic foaming grouting material according to any one of claims 1 to 7, characterized in that: The specific steps include: S1: weighing the raw materials in material A according to the stoichiometric amount, and stirring and mixing the raw materials to obtain material A; S2: Weigh the raw materials in material B according to the stoichiometric amount, and stir and mix the raw materials to obtain material B.

9. The method for preparing a two-component inorganic foaming grouting material according to claim 8, wherein: The stirring and mixing temperature in steps S1 and S2 is 20-30° C., and the mixing time is 10-50 min.

10. Use of the two-component inorganic foaming grouting material according to any one of claims 1 to 7 and the two-component inorganic foaming grouting material prepared by the method according to any one of claims 8 to 9 in coal mine goaf, characterized in that: The following steps are involved: Use a grouting pump to add material A and material B into the grouting system in a mass ratio of 1:3, and use a grouting machine to solidify and fill.

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