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

Abstract

The present application provides a kind of two-component inorganic foaming grouting material, comprising A and B, A is composed of carbonate, sodium silicate etc., B contains boric acid, phosphoric acid etc.The material uses calcium carbonate or magnesium carbonate to react with acid to produce carbon dioxide to realize foaming, through the synergistic effect of dispersing agent, thickening agent and foam stabilizer, the double acid system composed of boric acid and phosphoric acid, accurately control the viscosity of system, ensure the stability of foam, improve the compressive strength, flame retardant performance etc.Experimental results show that its compressive strength is more than 12MPa, foaming ratio is higher than 7 times, volume shrinkage is less than 6%, initial setting time is flexibly adjusted within a certain range.This material has excellent flame retardance and antistatic property, can fully penetrate into micropore and complex rock fracture, improve the repair effect of hidden structure, has broad application prospect in the field of coal mine filling and reinforcement, realizes safe controllability and green low carbonization.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of grouting filling and reinforcement, in particular to a two-component inorganic foaming grouting material, a preparation method and application thereof, which has excellent flame retardant performance, high foaming ratio, excellent mechanical properties and antistatic properties. BACKGROUND

[0002] In the process of coal mine production, gas accumulation and coal spontaneous combustion often occur in the areas such as mine empty roadway, upper corner, high fall area and space behind the frame, and filling foaming material is one of the key means to solve these problems. At present, the main filling foaming materials include cement-based inorganic foaming materials and polyurethane and phenolic resin-based organic foaming materials, which play an important role in coal mine safety management.

[0003] Polymer grouting material is one of the key technologies for filling mine empty roadway, preventing coal mine air leakage and inhibiting coal spontaneous combustion. At present, polymer air leakage blocking materials are mainly divided into organic and organic-inorganic composite types, among which the commonly used material is polymer solidified foam. With the advantages of controllable reaction time, high bonding strength and good permeability and diffusion, polymer foam has been widely used in coal mine grouting field at home and abroad, and common types include polyurethane foam, phenolic foam and urea-formaldehyde foam, which have played an important role in coal mine grouting engineering. However, polymer grouting foam materials also have some defects, for example, polyurethane foam generates a lot of heat when foaming, has poor thermal stability and is flammable, and releases toxic gases when burning; phenolic foam is easy to powder on the surface, has high toxicity of raw materials and high brittleness itself; urea-formaldehyde foam has poor water resistance, is easy to age and has high formaldehyde release. In addition, organic air leakage blocking materials generally have the disadvantages of high cost and poor flame retardancy. To solve these problems, the current main solution is to add a proper amount of inorganic material to the polymer matrix to combine the performance of organic and inorganic materials. Given the characteristics of abundant source, low cost, non-toxicity and certain 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, diatomite, silica, fly ash and gravel, as well as certain additives to form a polymer-based organic-inorganic composite grouting material, which has been widely used in coal mine reinforcement and filling field. Although the addition of inorganic materials can reduce the cost of organic materials and endow the material with certain properties, in the process of preparing air leakage blocking materials by mixed foaming, the inorganic materials with high viscosity will hinder the full foaming of the foam and affect the grouting efficiency.

[0004] Cement-based inorganic foamed grouting material plays an important role in the safety management of coal mines. Its low cost and easy access to raw materials make it widely used in many coal mines. Moreover, cement-based inorganic foamed grouting material has good fire resistance and corrosion resistance, which can adapt to the complex chemical environment of coal mine underground to some extent, further enhancing its practicality in the field of coal mines. However, this material also has some significant shortcomings. On the one hand, the curing time is relatively long, which may need to wait for a long time to fully cure and play a role in actual application, which may delay the treatment opportunity in some emergency situations that require quick repair and reinforcement. On the other hand, the early strength is low, and it is difficult to withstand large pressure and load in the early stage of curing, which seriously affects the support effect on the surrounding rock, thereby reducing the treatment efficiency of gas accumulation and coal seam spontaneous combustion. In addition, it is also prone to shrinkage cracking, which may cause cracks inside due to volume shrinkage during the curing process. These cracks not only reduce the overall strength and density of the material, but also provide new permeation paths for gas, increasing the risk of gas leakage, while weakening the reinforcement effect of the material on the coal seam, making it easier for coal to come into contact with oxygen in the air, thereby increasing the possibility of coal seam spontaneous combustion.

[0005] In view of the problems of existing organic grouting materials and cement-based inorganic grouting materials in terms of permeability, foam stability, mechanical properties and flame retardant properties, the present application aims to provide a two-component inorganic foamed grouting material. This material can fully penetrate into micro-pores and complex rock fissures, significantly improve the repair effect on micro-fissure structure, simultaneously optimize the compressive strength, flame retardancy, volume stability and curing time of the grouting material, realize the safety controllability and green low carbonization of filling and reinforcement in coal mine underground, and show a wide application prospect. SUMMARY

[0006] The present application aims to provide a two-component inorganic foamed grouting material and its preparation method and application. Calcium carbonate or magnesium carbonate is used as a foaming agent, and the dispersion agent and thickening agent are synergistically compounded to precisely control 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 curing. At the same time, the use of a double acid system composed of boric acid and phosphoric acid significantly improves the compressive strength, flame retardant properties, volume shrinkage rate, and flame retardant and antistatic effects of the material.

[0007] The present application provides a two-component inorganic foamed grouting material, which comprises a mass ratio of 1:3 of material A and material B, wherein:

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

[0009] The second material comprises the following raw materials 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, the average particle size of the calcium carbonate or magnesium carbonate is 0.1-10 μm, and further 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 the first material and the second material are mixed, the carbonate in the first material component chemically reacts with the acid in the second material component to generate carbon dioxide, and the thickening agent adjusts the viscosity of the mixed solution to be moderate to ensure the stability of the foam before solidification. The sodium silicate is solidified in an acidic environment to form a solidified foam state, the first material component is added slowly to neutralize the remaining acid after the neutralization reaction, and a stable phosphate precipitate is generated, thereby optimizing the performance and long-term safety of the grouting body.

[0011] In the coal mine grouting material, the boric acid and phosphoric acid double acid system has the following advantages compared with a single acid: (1) The borate ions generated by the hydrolysis of boric acid react with sodium silicate to form borosilicate gel containing Si-O-B network structure, while phosphoric acid reacts with sodium silicate to form silica gel (SiO2·nH2O), both of which fill the pores and form a more dense three-dimensional structure, which can improve the 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 performance of the filled body; at high temperatures, inorganic phosphate dehydrates to form a glassy substance rich in phosphorus, and borate decomposes to form glassy boron oxide (B2O3), forming a dense protective layer on the surface of the filled body, which insulates oxygen and heat, thereby playing a flame-retardant role. (3) The boric acid and phosphoric acid double acid system can realize staged solidification, improve the solidification efficiency, and phosphoric acid quickly reacts with sodium silicate to form silica gel, providing initial strength and achieving rapid plugging, shortening the initial setting time; while borosilicate gel is formed more slowly, which can prolong the final setting time, ensure that the grout fully penetrates the fissures, and realize precise control of the initial setting time and the final setting time, reduce the shrinkage rate of solidification, and have both rapid plugging and deep penetration ability, meet the grouting needs of flexible adaptation to emergency plugging and environmental adaptability, and balance efficient construction and long-term stability. In the mass fraction distribution of the double acid system, the mass fraction of boric acid is greater than that of phosphoric acid, to avoid the penetration deficiency caused by excessive phosphoric acid content leading to rapid solidification, or the insufficient initial strength caused by excessive boric acid content leading to slow reaction. Further preferably, the combination of 5-15 parts of boric acid and 1-5 parts of phosphoric acid is selected.

[0012] Preferably, the dispersant is sodium dodecyl benzene sulfonate and sodium polyacrylate, and the mass ratio of sodium dodecyl benzene sulfonate and sodium polyacrylate is 1:0.5-2. Sodium dodecyl benzene sulfonate is an anionic surfactant, and the hydrophilic group sulfonic acid group in the molecule can ionize a large number of negative ions in water, which can be adsorbed on the surface of calcium carbonate particles to make the surface of calcium carbonate particles carry negative charges. Similarly, the carboxylate ions dissociated from sodium polyacrylate in water can be adsorbed on the surface of calcium carbonate particles to form a strong adsorption layer, and also can be adsorbed on the surface of calcium carbonate particles to make the surface of calcium carbonate particles carry negative charges. Due to the repulsion of like charges, electrostatic repulsion will be generated between calcium carbonate or magnesium carbonate particles, which will hinder the mutual approach and agglomeration of particles, thereby improving the dispersibility of calcium carbonate or magnesium carbonate in water. Moreover, the molecular chain of sodium polyacrylate has a certain length and flexibility. When sodium polyacrylate is adsorbed on the surface of calcium carbonate or magnesium carbonate particles, a steric hindrance layer will be formed on the surface of the particles, which further increases 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. 2 / Mg 2+ Due to the repulsion of like charges, electrostatic repulsion will be generated between calcium carbonate or magnesium carbonate particles, which will hinder the mutual approach and agglomeration of particles, thereby improving the dispersibility of calcium carbonate or magnesium carbonate in water. Moreover, the molecular chain of sodium polyacrylate has a certain length and flexibility. When sodium polyacrylate is adsorbed on the surface of calcium carbonate or magnesium carbonate particles, a steric hindrance layer will be formed on the surface of the particles, which further increases 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-15 million Daltons.

[0014] Preferably, the thickening agent is xanthan gum and polyacrylamide, and the mass ratio of xanthan gum and polyacrylamide is 1:0.2-0.5. Xanthan gum is a high molecular weight polysaccharide, and the molecular chain contains a large number of hydrophilic groups such as hydroxyl and carboxyl groups, which can form hydrogen bonds with water molecules. After dissolution, a colloidal solution with three-dimensional network structure will be formed, thereby increasing the viscosity of the system. Calcium carbonate or magnesium carbonate particles are wrapped in viscous solution, and their movement is limited, making it difficult for them to collide and agglomerate, thereby playing a suspension stabilizing role. Polyacrylamide is a linear high molecular weight polymer, and the three-dimensional network of xanthan gum and the linear chain of PAM interpenetrate to form a more dense composite gel structure, further improving the viscosity of the solution, further inhibiting the precipitation of particles, playing a role in stabilizing the system, and being very beneficial to the dispersion effect of calcium carbonate or magnesium carbonate in water.

[0015] The foaming agent of the foamed grouting material can effectively foam under the conditions of stirring, blowing and the like, but the formed foam has poor stability and is difficult to exist for a long time. In order to prolong the stable time of the foam, a small amount of foam stabilizer is often added to the foaming agent solution to change the surface physical and chemical properties of the bubble liquid film, thereby improving the foam stability. Among them, appropriately increasing the viscosity of the slurry is a common method to improve the foam stability. If the viscosity of the slurry is too low, it is not conducive to the sealing of the internal gas, resulting in a low bubble nucleation rate. If the viscosity of the slurry is too high, it will inhibit the nucleation and development of the bubbles, affect the overall expansion effect of the material, and also hinder the uniform dispersion of the foaming agent in the slurry. The foam stabilizer used is a combination of polyethylene oxide and a stearate salt, and preferably the stearate salt is one or more of calcium stearate, magnesium stearate and zinc stearate. The mass ratio of polyethylene oxide and stearate salt is 4:0.5-2. The stearate salt as a foam stabilizer can improve the viscosity and strength of the bubbles, make the bubbles uniform, dense and stable, and avoid the large-area rupture of the bubbles in the filling material when the bubbles are in contact with air or collide with each other. The polyethylene oxide (PEO polymer) can significantly increase the viscosity of the foaming liquid due to the presence of a large number of -C-O-C structures, thereby forming a viscous and stable sol solution.

[0016] In the coal mine grouting material, if there is an excess of phosphoric acid in the system, the hydrolysis-polycondensation reaction of sodium silicate will be inhibited due to the strong acidic environment (pH is too low), which will hinder the formation of gel network, resulting in delayed curing, uneven structure and internal pore generation. After grouting, the residual phosphoric acid will continue to destroy the silicon-oxygen skeleton, reduce the mechanical strength and durability, and at the same time, the soluble phosphate is precipitated or reacts with the surrounding rock to cause chemical corrosion, dissolution of holes and groundwater pollution, which threatens the stability of the roadway. By accurately controlling the ratio and adding an acid-removing agent, the excess phosphoric acid can be neutralized to generate stable phosphate precipitates, thereby optimizing the performance and long-term safety of the grouting body.

[0017] Preferably, the acid-removing agent is one or both of polyaluminum chloride and polyferric sulfate. After polyaluminum chloride is dissolved in water, Al 3 ions are generated, and polyferric sulfate is dissolved in water to form Fe 3+ ions. Al ions or Fe ions can react with phosphate ions to form insoluble aluminum phosphate precipitates or iron sulfate precipitates, thereby removing excess phosphoric acid from the slurry to achieve the purpose of acid removal.

[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. The addition of a complexing agent in the slurry reduces the precipitation or stratification caused by metal ions such as Ca 2+ and Mg 2+) form stable complex, prevent it from forming precipitate with phosphate / borate, realize uniform stable solution system by inhibiting metal ion interference.

[0019] Further, the additives of the first material include at least one of a pH regulator, an enhancer, and an anti-freezing agent.

[0020] The application also provides a preparation method of the two-component inorganic foaming grouting material, specifically including the following steps:

[0021] S1: the raw materials in the first material are weighed according to the stoichiometric amount, and the raw materials are stirred and mixed uniformly to obtain the first material;

[0022] S2: the raw materials in the second material are weighed according to the stoichiometric amount, and the raw materials are stirred and mixed uniformly to obtain the second material.

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

[0024] The application also provides an application of the two-component inorganic foaming grouting material in a coal mine, including the following steps: the first material and the second material are added to a grouting system according to a mass ratio of 1:3 by using a grouting pump, and solidification filling is performed by using a grouting machine.

[0025] The two-component inorganic foaming grouting material has at least the following advantages or beneficial effects:

[0026] The two-component inorganic foaming grouting material is a high-flowability slurry that can fully penetrate into micro-pores and complex rock fissures, greatly improving the repair effect on concealed structures; through the synergistic effect of the compounded dispersant and thickening agent, the system viscosity is precisely controlled to ensure uniform particle suspension and bubble stability, so that the slurry has excellent flowability during pumping. The introduced boric acid-phosphoric acid dual acid system synchronously optimizes the compressive strength, flame retardancy, volume stability and solidification time of the grouting material through a staged reaction mechanism (phosphoric acid rapid setting nucleation, boric acid slow setting reinforcement), realizes the safety controllability and green low carbonization of filling and reinforcement in the coal mine, and has a wide application prospect. DETAILED DESCRIPTION

[0027] To more clearly illustrate the purpose, technical solutions and advantages of the present application, the following will be described in detail through specific embodiments. It should be pointed out that these embodiments are only used to illustrate the present application, and do not limit the protection scope thereof, and the actual protection scope of the present application should be defined by the claims.

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

[0029] I. Preparation of two-component inorganic foaming grouting material

[0030] The present application relates to a preparation method of a two-component inorganic foaming grouting material, which comprises a mass ratio of 1:3 of material A and material B, and specifically comprises the following steps:

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

[0032] S2: Preparation method of material B: according to the components and contents of material B in Table 1, use a high-speed stirring barrel, stir and mix at 25°C and 500 r / min for 15 min 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 of 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 of 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 of 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 of Example 2.

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

[0044]

[0045]

[0046] II. Performance evaluation

[0047] The two-component inorganic foamed grouting material prepared in the examples and the comparative examples is applied in the goaf of a coal mine, including the following steps: adding the A material and the B material in a mass ratio of 1:3 to a grouting system by using a grouting pump, and curing and filling by using a grouting machine.

[0048] 1. Gel time test

[0049] The gel time of the plugging material is crucial for grouting and plugging construction. A reasonable gel time allows the slurry to fully spread in the stratum. If the gel time is too long, the slurry is prone to loss in the fracture pore, making it difficult to effectively plug the fracture. If the gel time is too short, the slurry is difficult to fully spread in the fracture network of the coal seam, affecting the grouting and plugging effect of the coal body. Therefore, the gel time of the material should be reasonably controlled according to the actual construction situation.

[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] A good plugging material with expansion performance can produce a certain volume expansion during the curing process, allowing it to closely adhere to the surface of the coal body fracture and fully fill the corners of the fracture, thereby achieving full sealing of the coal body fracture. Conversely, if the plugging material shrinks in volume after curing, the part that was closely combined with the surface of the coal body fracture will have gaps due to shrinkage, causing the material to separate from the surface of the coal body fracture. In this way, the originally plugged fracture will again form a gas leakage channel, affecting the sealing effect of the coal body and possibly adversely affecting the safety of the coal mine and other aspects. Therefore, in order to ensure that the coal body fracture can be effectively and durably plugged, the plugging material must have certain volume expansion performance during use and must have very low volume expansion rate after curing.

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

[0054] 3. Material mechanical strength test

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

[0056] According to the requirements of the AQ / T 1089-2020 standard, the prepared material slurry was first poured into a 10 cm x 10 cm x 10 cm mold, and after 24 h, the test sample was removed from the mold and placed in an environment of 20°C and 50% relative humidity for 7 d of curing. The compressive strength of the material at 7 d was tested, and the average value of 5 test samples was selected as the test result of each group.

[0057] 4. Foaming ratio

[0058] In the process of filling coal mines, good foaming ratio has many advantages for grouting materials, such as rapid filling of space, saving of material usage and cost, and improvement of construction efficiency. At the same time, it can effectively block gas and prevent coal instability, and enhance engineering safety. However, if the foaming ratio is too low, a large amount of material is needed to fill the space, resulting in increased cost and reduced construction efficiency, and poor sealing and supporting effect. When the foaming ratio is too large, the material may shrink, crack, and other problems due to insufficient stability, affecting the filling effect and coal stability, and even requiring additional reinforcement measures, which increases the construction difficulty and cost. The foaming ratio was tested according to the requirements of the JC / T266-2011 "Foamed Concrete" standard.

[0059] Table 3 Performance of grouting materials of different examples and control examples

[0060]

[0061]

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

[0063] By comparing the results of Comparative Example 2 and Examples 5-8, it can be found that the average particle size of calcium carbonate or magnesium carbonate particles has a significant impact on the foaming ratio of the grouting material. When the average particle size of the particles decreases within a certain range, the specific surface area increases accordingly. This enables the particles to be more fully in contact with phosphoric acid and to undergo chemical reactions, accelerating the generation of carbon dioxide gas and forming more foam, thereby increasing the foaming ratio. The increase in the foaming ratio changes the gas-liquid ratio of the system, resulting in an extension of the stability time of the foam and an extension of the initial setting time of the grouting material. In addition, since the foamed material has a more stable volume during the curing process, the volume shrinkage rate is reduced, the volume change of the grouting material after curing is reduced, the pores and fractures 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] As can be seen by comparing Comparative Examples 1-8 with Example 2, the dispersant, thickening agent and foam stabilizer are not used in a compounded manner, but only a single dispersant, thickening agent and foam stabilizer is used, resulting in a decrease in the dispersibility of calcium carbonate or magnesium carbonate in the water system, a decrease in the foaming ratio, 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 and final setting times; at the same time, the grouting material cannot tightly fill the pores and fractures of the coal rock mass, thereby reducing the mechanical strength of the coal mine filling, increasing the volume shrinkage rate, and significantly affecting the performance of the grouting material.

[0065] As can be seen by comparing Comparative Examples 1-8 with Example 2, if the dispersant, thickening agent and foam stabilizer are not used in a compounded manner, but only a single component is used, the dispersibility of calcium carbonate or magnesium carbonate in the water system will be poor. The decrease in dispersibility results in insufficient reaction of calcium carbonate or magnesium carbonate with phosphoric acid, a decrease in the efficiency of carbon dioxide foam generation, and a decrease in the foaming ratio. Due to the decrease in the foaming ratio, the relative content and concentration of water glass in the slurry are relatively high, which can accelerate the coagulation and hardening reaction of the slurry, shorten the initial setting time, limit the construction operation time, and increase the risk of pipe blockage. At the same time, due to the low foaming ratio and insufficient filling performance of the slurry, the grouting material cannot tightly fill the pores and fractures of the coal rock mass, the insufficient filling of the pores reduces the mechanical support capacity of the coal rock mass, and the mechanical strength of the coal mine filling is reduced. In addition, due to the low foaming ratio and poor volume stability of the slurry, the volume shrinkage rate of the grouting material increases during the curing process, the pores generated by material shrinkage can weaken the integrity of the coal rock mass, thereby significantly affecting the overall performance of the grouting material and failing to effectively improve the safety and stability of the coal mine.

[0066] III. Flame retardancy and antistatic property of the grouting material

[0067] The product prepared by using Example 2 was tested for flame retardance and antistatic property according to MT / T113-1995 "General test method and determination rule for flame retardance and antistatic property of polymer products for underground coal mine". The test results are as follows:

[0068] Table 5 Report on detection of flame retardance and antistatic property of products for underground coal mine

[0069]

[0070] The above detection results show that the safety detection report of flame retardance and antistatic property of the product using the grouting material of Example 2 shows that all detection items are qualified. In the alcohol torch and alcohol lamp burning test, the flaming combustion time and non-flaming combustion time of the material are far lower than the maximum value of the technical requirement, which shows that it has excellent flame retardance and can quickly extinguish the flame to prevent the spread of fire. The surface resistance detection results also show that the upper and lower surface resistances of the material are lower than the technical requirement, and it has good antistatic property and can effectively reduce the risk of fire or explosion caused by static discharge. This fully shows that the polymer product can provide reliable safety guarantee for the working environment when used in underground coal mine, and meets the strict requirements of underground coal mine on the flame retardance and antistatic property of the material.

[0071] The above examples are only provided for illustrating the present application, and are not intended to limit the possible implementation manners of the present application. Based on the disclosed content of the present application, those skilled in the related art can make various modifications and adjustments. It is impossible or unnecessary to list all possible implementation manners. Any modification, equivalent replacement or improvement made within the basic principles and scope of the present application should be considered as falling within the protection scope of the present application.

Claims

1. A two-component inorganic foamed grouting material, characterized by, The composition comprises a mass ratio of 1:3 of the first material and the second material, wherein: The first material comprises the following raw materials in parts by weight: 20-45 parts of a carbonate, 15-40 parts of sodium silicate, 3-15 parts of a dispersing agent, 2-6 parts of a thickening agent, 3-8 parts of a foam stabilizer, 1-10 parts of an acid remover, 1-10 parts of an auxiliary agent, 40-100 parts of water; the auxiliary agent comprises at least one of a pH regulator, a reinforcing agent, and an anti-freezing agent; The second material 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, 20-50 parts of water; the complexing agent is at least one of ethylenediaminetetraacetic acid and its salt, citric acid and its salt, or tartaric acid and its salt; The dispersing agent is sodium dodecyl benzene sulfonate and sodium polyacrylate, wherein the mass ratio of sodium dodecyl benzene sulfonate to sodium polyacrylate is 1:0.5-2; The thickening agent 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 a stearate, wherein the mass ratio of polyethylene oxide to the stearate is 4:0.5-2.

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

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

6. A method for preparing a two-component inorganic foamed grouting material according to any one of claims 1 to 5, characterized in that Specifically comprising the following steps: S1: weighing the raw materials in the first material according to the stoichiometric amount, and stirring and mixing the raw materials uniformly to obtain the first material; S2: weighing the raw materials in the second material according to the stoichiometric amount, and stirring and mixing the raw materials uniformly to obtain the second material.

7. The method of claim 6, wherein the two-component inorganic foamed grouting material is prepared by mixing the first component and the second component in a weight ratio of 1:1 to 1:

3. The stirring and mixing temperature in steps S1 and S2 is 20-30°C, and the mixing time is 10-50 min.

8. The application of two-component inorganic foamed grouting material as claimed in any one of claims 1-5 and two-component inorganic foamed grouting material prepared by the method of claim 6 or 7 in coal mine goaf, characterized in that, The steps comprise: The first material and the second material are added to the grouting system in a mass ratio of 1:3 by using a grouting pump, and solidification filling is performed by using a grouting machine.

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