A composite grouting reinforcement material for mining and preparation method thereof

Abstract

The present invention relates to a composite grouting reinforcement material for mining and a preparation method thereof. The composite grouting reinforcement material for mining comprises a component A and a component B. When used, the volume ratio of component A to component B is 1:(0.95-1.05). Component A comprises the following raw materials in parts by weight: 40-70 parts of polyether polyol, 10-30 parts of flame retardant, 25-40 parts of modified fly ash, 0.1-0.3 parts of catalyst, and 0.1-0.3 parts of anti-settling dispersant. Component B comprises the following raw materials in parts by weight: 40-70 parts of isocyanate, 10-30 parts of flame retardant, 25-40 parts of modified fly ash, and 0.1-0.3 parts of anti-settling dispersant. The present invention is an environmentally friendly mining reinforcement material. It introduces inexpensive and readily available fly ash into a polyurethane system in an organic + inorganic composite manner, reducing the proportion of organic raw materials used and product costs while also improving the overall performance of the material.

Description

Technical Field

[0001] The present invention relates to the technical field related to mining reinforcement materials, and in particular to a mining composite grouting reinforcement material and a preparation method thereof. Background Art

[0002] As coal mining deepens, complex geological conditions such as weak rock formations and fault fracture zones often arise during excavation of deep tunnel surrounding rock. Grouting reinforcement is commonly used in deep tunnel excavation and face mining. Grouting equipment injects reinforcement material into the cracks of the broken surrounding rock. After a cross-linking and curing reaction, the resulting consolidation binds the loose, broken coal and rock mass into a dense network framework, improving the surrounding rock stability and structural bearing capacity, preventing accidents such as roof falls and rock spalling during mining, and ensuring safe and efficient coal mine production.

[0003] Grouting reinforcement is currently one of the main means of controlling the surrounding rock of deep tunnels. The performance of the reinforcement material plays a decisive role in the reinforcement effect. Commonly used polyurethane organic reinforcement materials such as Marisan have disadvantages such as high cost, violent reaction exotherm, poor flame retardant effect, and easy to cause underground fires. With the implementation of the new safety standard AQ / T 1089-2020, the curing temperature of organic reinforcement materials is strictly limited to less than 100°C. Most products on the market sacrifice some mechanical properties to meet the new safety standard's requirements for curing temperature, which is difficult to meet the actual use needs of coal mines. In order to improve the strength, the curing temperature of some products is difficult to meet the requirements of the new safety standard.

[0004] In the field of mine reinforcement, polyurethane-based organic materials are commonly used for two-liquid grouting reinforcement. Component A is generally a polyether or polyester polyol, and component B is generally an isocyanate. Essentially, the hydroxyl groups of component A react with the isocyanate groups (-NCO) of component B to form a block copolymer containing alternating soft and hard segments containing carbamate groups (-NHCOO-). However, these materials have drawbacks such as high cost, intense reaction exotherm, poor flame retardancy, and a high risk of fire.

[0005] Organic-inorganic composite grouting materials are a major development direction in the future. At present, silicate-modified polyurethane materials have been widely used in engineering practice. Component A is a sodium silicate aqueous solution, and component B is still isocyanate. After components A and B are mixed, the CO2 generated by the isocyanate in contact with water further reacts with the silicate to solidify, introducing Si-O segments into the organic structure, and ultimately forming a three-dimensional interpenetrating network of organic phase (polyurethane network) and inorganic phase (inorganic silicate network). Although it has the advantages of low reaction temperature, good flame retardancy, and adaptability to water-bearing coal seams, the consolidated body of this type of material is brittle, has high hardness, and weak adhesion to the coal seam. It is difficult to ensure the reinforcement effect under special working conditions. The actual use effect is still not ideal, and it still cannot completely replace pure organic polyurethane materials.

[0006] Application No. 202410349736.3, “A Fly Ash / Polyurethane Grouting Composite Material for Mining and Its Preparation Method”, adds 20% untreated fly ash to component A, and introduces a prepolymer into component B to reduce the isocyanate group (-NCO) content to reduce the overall reaction temperature, improve flame retardancy, and achieve a compressive strength of 60MPa. Application No. 202410212007.3, “Low-temperature Coal Rock Reinforcement Grouting Material for Mining and Its Preparation Method”, wet-modifies diatomaceous earth with silicone oil solution and then adds it to component A at a ratio of 10%. The curing temperature and compressive strength are also tested, and the compressive strength can reach 60MPa. However, both patents are only filled with a single component, and the total amount of inorganic matter added is still relatively low, failing to give full play to the cost advantages and reinforcing properties of inorganic fillers. In addition, wet modification requires filtration and drying to obtain the product, and the process is relatively complicated and the cost is high. The invention adopts a dry process to carry out surface modification on inorganic mineral powder, and then introduces the powder into a polyurethane system to prepare a low-cost, high-performance composite grouting reinforcement material for mining. Summary of the Invention

[0007] In order to solve one or more technical problems existing in the prior art, the present invention provides a composite grouting reinforcement material for mining and a preparation method thereof.

[0008] The technical solution of the present invention to solve the above technical problems is as follows: a composite grouting reinforcement material for mining, comprising component A and component B, wherein the volume ratio of component A to component B is 1:(0.95-1.05) when in use;

[0009] Component A includes the following raw materials in parts by weight: 40-70 parts of polyether polyol, 10-30 parts of flame retardant, 25-40 parts of modified fly ash, 0.1-0.3 parts of catalyst, and 0.1-0.3 parts of anti-settling dispersant;

[0010] Component B comprises the following raw materials in parts by weight: 40-70 parts of isocyanate, 10-30 parts of flame retardant, 25-40 parts of modified fly ash, and 0.1-0.3 parts of anti-settling dispersant.

[0011] The beneficial effects of the present invention are as follows: the composite grouting reinforcement material for mining of the present invention introduces cheap and readily available inorganic fillers such as fly ash as reinforcing materials into the polyurethane system in an organic + inorganic composite manner, thereby reducing the proportion of organic raw materials used and lowering product costs. The obtained product has a low curing temperature, good flame retardant effect, and excellent mechanical properties, with a compressive strength of up to 104Mpa, far exceeding the safety standard requirements (greater than 40MPa), and is significantly better than similar products on the market. The tensile elongation at break and the compressive strain are large, the product has high toughness, and can better adapt to the tunnel environment with greater disturbance caused by mining. The advantages of the composite grouting reinforcement material for mining of the present invention are due to the full play of the excellent properties of fly ash itself, and the surface polarity of fly ash is made close to that of polymer resin through appropriate modification means, thereby improving the interface compatibility between the two, so that fly ash can be better dispersed and filled in the resin matrix, thereby enhancing the reinforcement effect.

[0012] Using inorganic minerals such as fly ash to fill and modify pure organic polyurethane materials, on the one hand, inorganic minerals have strong chemical stability. When introduced into the polyurethane system, they can reduce the proportion of organic raw materials used, reduce reaction heat release, and lower the curing temperature. On the other hand, they can also act as a reinforcing phase to form a synergistic effect with the resin matrix material, exerting a reinforcing effect. However, inorganic fillers have poor wetting and dispersion properties in the resin matrix. Therefore, the filler must be surface modified to change its surface from hydrophilic to oleophobic, improving the interfacial compatibility between the two, allowing the filler to be better dispersed and filled in the resin matrix, thereby enhancing the reinforcement effect.

[0013] On the basis of the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, the polyether polyol has a hydroxyl value of 150 to 550 mgKOH / g, a functionality of 2 to 3, and a viscosity of 250 to 600 mPa·s / 25°C.

[0015] Optionally, the hydroxyl value of the polyether polyol is 150 mgKOH / g, 230 mgKOH / g, 325 mgKOH / g, 420 mgKOH / g, 550 mgKOH / g, the functionality is 2 or 3, and the viscosity is 250 mPa·s / 25°C, 300 mPa·s / 25°C, 350 mPa·s / 25°C, 450 mPa·s / 25°C, 600 mPa·s / 25°C.

[0016] The polyether polyol of component A of the present invention can be selected from polyols with a single hydroxyl value, a single viscosity value and a single functionality, or can be compounded from polyols with two or more hydroxyl values, viscosities and functionalities.

[0017] Furthermore, the isocyanate has an isocyanate content of 30% to 32% and a viscosity of 150 to 450 mPa·s / 25°C.

[0018] Optionally, the isocyanate content in the isocyanate is 30%, 30.5%, 31%, 31.5%, or 32%, and the viscosity is 150mPa·s / 25°C, 200mPa·s / 25°C, 250mPa·s / 25°C, 300mPa·s / 25°C, 350mPa·s / 25°C, 400mPa·s / 25°C, or 450mPa·s / 25°C.

[0019] The isocyanate of component B of the present invention can be selected from isocyanates with a single isocyanate content and a single viscosity value, or can be compounded with isocyanates with two or more isocyanate contents and viscosity values.

[0020] Furthermore, the flame retardant includes one or more of tris(2-chloropropyl) phosphate, tris(2-chloroethyl) phosphate, triethyl phosphate, triphenyl phosphate, and tricresyl phosphate.

[0021] Furthermore, the catalyst is selected from one of dibutyltin dilaurate, lead octoate, stannous octoate, bismuth isooctanoate and zinc isooctanoate.

[0022] Furthermore, the anti-settling dispersant is selected from one or more of polyethylene wax, castor oil derivatives, polyamide-modified alkyd resin, polyurethane-modified alkyd resin, polymer carboxylic acid and silicone copolymer, and modified polyurea thickener.

[0023] A method for preparing the above-mentioned composite grouting reinforcement material for mining comprises the following steps:

[0024] S1, pretreating fly ash to obtain modified fly ash;

[0025] S2, adding the raw materials of component A to the reactor in sequence, stirring and dispersing them evenly under nitrogen protection, and maintaining the vacuum degree for a first preset time; adding the raw materials of component B to the reactor in sequence, stirring and dispersing them evenly under nitrogen protection, and maintaining the vacuum degree for a second preset time;

[0026] S3, mixing the evenly dispersed component A and component B according to a preset volume ratio to obtain the composite grouting reinforcement material for mining.

[0027] The beneficial effects of the present invention are as follows: the preparation method of the composite grouting reinforcement material for mining of the present invention has a simple process, the prepared product has a low curing temperature, good flame retardant effect, excellent mechanical properties and high shear strength.

[0028] Furthermore, in S1, the fly ash is pretreated, including sorting the fly ash to a D97 of 800-2500 mesh, placing the sorted fly ash in a mixing mixer, heating and activating the fly ash at a first preset temperature for 30-90 minutes, then slowly adding a surface modification solution, wherein the mass of the surface modification solution is 2.5-10% of the mass of the fly ash, and uniformly mixing the surface modification solution and the fly ash at a second preset temperature to obtain modified fly ash. The first preset temperature is 110° C. to 130° C., and the second preset temperature is 50° C. to 70° C.

[0029] The beneficial effects of this further approach include: by sorting and modifying fly ash, the surface polarity of the fly ash approaches that of the polymer resin, improving interfacial compatibility between the two, enabling better dispersion and filling of the fly ash within the resin matrix, and enhancing the reinforcement effect. Dry-process modification of fly ash has a wider range of industrial applications. Dry-processing is more suitable for surface modification of inorganic mineral powders, offering relatively low costs and a simpler process.

[0030] Furthermore, the surface modification solution is prepared by mixing the surface modifier and ethanol in a preset mass ratio, and then adding acetic acid solution to adjust the pH value to 4-6 to obtain the surface modification solution.

[0031] Furthermore, the surface modifier includes at least one of silane coupling agent, aluminate coupling agent, titanate coupling agent, zirconium aluminate coupling agent, higher fatty acids and their salts, higher phosphate salts, higher amine salts, polyethylene glycol, polyacrylic acid, sodium polyacrylate, ammonium polyacrylate, polyacrylamide, and silicone oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a compressive strain chart of the mining composite grouting reinforcement material under different compressive stresses according to Example 3 of the present invention;

[0033] Figure 2 This is a tensile deformation chart of the mining composite grouting reinforcement material according to Example 3 of the present invention at different tensile strengths. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] The technical solutions of the present invention are described below by means of specific embodiments. It should be understood that the one or more steps mentioned in the present invention do not exclude the presence of other methods and steps before and after the combination step, or that other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the numbering of each method step is only for the purpose of identifying each method step, and is not intended to limit the order of arrangement of each method or to define the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantial changes in the technical content, may also be considered as the scope of implementation of the present invention.

[0036] The sources of the raw materials and instruments used in the examples are not particularly limited and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0037] Example 1

[0038] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0039] Component A includes the following raw materials in parts by weight: 55 parts of polyether polyol, 20 parts of flame retardant, 25 parts of modified fly ash, 0.1 parts of catalyst, and 0.2 parts of anti-settling dispersant;

[0040] Component B includes the following raw materials in parts by weight: 55 parts of isocyanate, 20 parts of flame retardant, 25 parts of modified fly ash, and 0.2 parts of anti-settling dispersant.

[0041] The polyether polyol was H305, purchased from Hongbaoli Group Co., Ltd. The isocyanate was polymethylene polyphenyl isocyanate (Huntsman 5005). The flame retardant was TCPP, purchased from Zhejiang Wansheng Co., Ltd. The catalyst was dibutyltin dilaurate (Evonik DABCO T-12). The anti-settling dispersant was DeuRheo 202P from Hemingway.

[0042] A method for preparing the above-mentioned composite grouting reinforcement material for mining comprises the following steps:

[0043] S1, pre-treating fly ash to obtain modified fly ash; the fly ash is selected from Guoneng Shouguang Power Generation Co., Ltd.;

[0044] S2, adding the raw materials of component A to the reactor in sequence, stirring them thoroughly for 30 to 90 minutes under nitrogen protection to make them evenly dispersed, and maintaining the vacuum degree for 10 to 30 minutes; adding the raw materials of component B to the reactor in sequence, stirring them thoroughly for 30 to 90 minutes under nitrogen protection to make them evenly dispersed, and maintaining the vacuum degree for 10 to 30 minutes;

[0045] S3, the evenly dispersed component A and component B were mixed in a volume ratio of 1:1, stirred with an electric stirrer (600 rpm / min) for about 30 seconds, and poured into the corresponding mold after mixing evenly to prepare the test block.

[0046] In S1, the fly ash is pretreated, including sorting the fly ash to a D97 of 800-2500 mesh, placing the sorted fly ash in a stirring mixer, heating and activating the fly ash at 110° C. for 1 hour, and then slowly adding a surface modification solution with a mass of 5% of the mass of the fly ash, and uniformly mixing the surface modification solution and the fly ash at 60° C. to obtain modified fly ash.

[0047] Furthermore, the preparation process of the surface modification solution is as follows: the surface modification solution is prepared by mixing silane coupling agent KH-560, titanate coupling agent NDZ-201 and ethanol solution in a mass ratio of 1:1:8, and then adding a small amount of acetic acid solution to adjust the pH to 4-6.

[0048] Titanate coupling agent NDZ-201 contains a single alkoxy group and three groups that interact with the organic binder. Silane coupling agent KH-560 has three alkoxy groups and one glycidyloxypropyl reactive functional group. The alkoxy group chemically reacts with the hydroxyl groups on the fly ash surface, adsorbing onto the inorganic particles. It also undergoes a ring-opening reaction with the epoxy bond in the glycidyloxypropyl group at the end of the silane. The two coupling agents produce a synergistic effect, forming a strong organic coating on the particle surface. This improves the spatial structural instability of titanate alone and the limited number of groups available for chemical bonding or physical entanglement with organic polymer molecules when silane alone is used. The combination of the two coupling agents enhances the bonding strength with the organic polymer matrix, improving the dispersibility and interfacial compatibility of the inorganic filler.

[0049] Example 2

[0050] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0051] Component A includes the following raw materials in parts by weight: 50 parts of polyether polyol, 20 parts of flame retardant, 30 parts of modified fly ash, 0.1 parts of catalyst, and 0.2 parts of anti-settling dispersant;

[0052] Component B includes the following raw materials in parts by weight: 50 parts of isocyanate, 20 parts of flame retardant, 30 parts of modified fly ash, and 0.2 parts of anti-settling dispersant.

[0053] The rest is the same as Example 1.

[0054] Example 3

[0055] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0056] Component A includes the following raw materials in parts by weight: 45 parts of polyether polyol, 20 parts of flame retardant, 35 parts of modified fly ash, 0.1 parts of catalyst, and 0.2 parts of anti-settling dispersant;

[0057] Component B includes the following raw materials in parts by weight: 45 parts of isocyanate, 20 parts of flame retardant, 35 parts of modified fly ash, and 0.2 parts of anti-settling dispersant.

[0058] The rest is the same as Example 1.

[0059] Example 4

[0060] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0061] Component A includes the following raw materials in parts by weight: 40 parts of polyether polyol, 20 parts of flame retardant, 40 parts of modified fly ash, 0.1 parts of catalyst, and 0.2 parts of anti-settling dispersant;

[0062] Component B includes the following raw materials in parts by weight: 40 parts of isocyanate, 20 parts of flame retardant, 40 parts of modified fly ash, and 0.2 parts of anti-settling dispersant.

[0063] The rest is the same as Example 1.

[0064] Comparative Example 1

[0065] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0066] Component A includes the following raw materials in parts by weight: 80 parts of polyether polyol, 20 parts of flame retardant, and 0.1 parts of catalyst;

[0067] Component B includes the following raw materials in parts by weight: 80 parts of isocyanate and 20 parts of flame retardant.

[0068] The rest is the same as Example 1.

[0069] Comparative Example 2

[0070] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0071] Component A includes the following raw materials in parts by weight: 65 parts of polyether polyol, 35 parts of modified fly ash, 0.1 parts of catalyst, and 0.2 parts of anti-settling dispersant;

[0072] Component B includes the following raw materials in parts by weight: 65 parts of isocyanate and 35 parts of flame retardant.

[0073] The rest is the same as Example 1.

[0074] Comparative Example 3

[0075] A composite grouting reinforcement material for mining in this embodiment includes component A and component B, wherein the volume ratio of component A to component B is 1:1;

[0076] Component A includes the following raw materials in parts by weight: 65 parts of polyether polyol, 35 parts of flame retardant, and 0.1 parts of catalyst;

[0077] Component B includes the following raw materials in parts by weight: 65 parts of isocyanate and 35 parts of modified fly ash.

[0078] The rest is the same as Example 1.

[0079] The performance of the composite grouting reinforcement materials for mining prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was tested.

[0080] The test method adopts the production safety industry standard AQ / T 1089-2020 to test the curing temperature of components A and B, as well as the compressive strength, tensile strength and oxygen index of the solidified body.

[0081] The test results are shown in Table 1. Figure 1 and Figure 2 As shown:

[0082] Table 1 Performance test table of composite grouting reinforcement materials for mining

[0083] Curing temperature / ℃ Compressive strength / Mpa Tensile strength / Mpa Oxygen index / % Example 1 99.6℃ 79.7Mpa 14.8Mpa 28.0％ Example 2 96.0℃ 90.0Mpa 15.9Mpa 28.2％ Example 3 94.5℃ 104.2Mpa 16.6Mpa 28.7％ Example 4 92.9℃ 107.9Mpa 16.0Mpa 29.0％ Comparative Example 1 130℃ 46.8Mpa 13.1Mpa 25.5％ Comparative Example 2 115℃ 69.0Mpa 13.6Mpa 27％ Comparative Example 3 119℃ 63.5Mpa 14.0Mpa 26.8％

[0084] As shown in Table 1, from Example 1 to Example 4, as the weight of the modified fly ash in Component A and Component B increases, the content of organic matter decreases accordingly, the curing temperature of the composite grouting reinforcement material for mining gradually decreases, and the compressive strength, tensile strength, and oxygen index generally show an upward trend, indicating that the modified fly ash can be well wetted and dispersed in the organic polymer matrix, improving the mechanical properties and flame retardant properties of the composite material. When the weight of the modified fly ash in Example 4 is increased to 40 parts, the overall performance is not much different from that of Example 3. However, considering that the high solid content will reduce the storage stability of the material and the high viscosity of the slurry is not conducive to grouting construction, considering the economic efficiency of the product and the convenience of construction, the weight of the modified fly ash in Example 3 is the best choice. This is equivalent to using a certain amount of solid waste fly ash as a functional filler to achieve a partial low-cost replacement of the organic matter in Components A and B.

[0085] In Example 3, when the overall filling amount of the modified fly ash is 35%, the curing temperature is 94.5°C, the compressive strength is 104.2MPa, and the tensile strength is 16.6MPa. Figure 1 As shown, the maximum compressive strength deformation is 55%, and the oxygen index is 28.7%. This demonstrates that the modified fly ash has a beneficial effect on strengthening and toughening the polyurethane resin. Furthermore, since fly ash is formed by the high-temperature combustion of pulverized coal in a furnace, it inherently possesses excellent properties such as non-combustibility, high-temperature resistance, and low thermal conductivity. Compounding with organic polymers enhances flame retardancy. This product addresses current challenges in the field of mine reinforcement materials while achieving high-value resource utilization of fly ash, a coal-based solid waste.

[0086] In Comparative Example 1, neither component A nor component B is added with modified fly ash. The curing temperature reaches 130°C and the oxygen index is lower than 28%, which does not meet the safety standards. The safety is poor. In particular, when a large volume of slurry accumulates at the grouting location, the large amount of reaction heat released during curing is difficult to dissipate, which may cause spontaneous combustion of the surrounding coal seams and lead to fire accidents. Comparative Examples 2 and 3 only add modified fly ash to a single component, while maintaining the isocyanate index (n (-NCO) :n (-OH) ) to make them comparable. The results show a significant reduction in curing temperature and a modest improvement in mechanical and flame retardancy, but they still do not fully meet safety standards. The compressive strength remains relatively low, making it poorly suited for complex geological conditions such as those found in highly deformed, soft coal and rock tunnels. Furthermore, single-component filling results in a significant difference in viscosity between components A and B, making it difficult to precisely control the ratio of the two liquids during grouting, impacting the grouting effect.

[0087] The above examples are merely descriptions of specific embodiments of the present invention and do not limit the scope of the present invention. Those skilled in the art may make various modifications and changes based on the existing technology. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A composite grouting reinforcement material for mining, characterized in that: The invention comprises component A and component B, wherein the volume ratio of component A to component B is 1: (0.95-1.05); Component A includes the following raw materials in parts by weight: 40-70 parts of polyether polyol, 10-30 parts of flame retardant, 25-40 parts of modified fly ash, 0.1-0.3 parts of catalyst, and 0.1-0.3 parts of anti-settling dispersant; Component B includes the following raw materials in parts by weight: 40-70 parts of isocyanate, 10-30 parts of flame retardant, 25-40 parts of modified fly ash, and 0.1-0.3 parts of anti-settling dispersant; The modified fly ash is prepared by the following pretreatment method: fly ash is sorted to a D97 of 800 to 2500 mesh, the sorted fly ash is placed in a stirring mixer, the fly ash is heated and activated under a first preset temperature, a surface modification solution is slowly added, the mass of the surface modification solution is 4 to 6% of the mass of the fly ash, and the surface modification solution and the fly ash are uniformly mixed under a second preset temperature to obtain the modified fly ash; The surface modification solution is prepared by mixing silane coupling agent KH-560, titanate coupling agent NDZ-201 and ethanol solution, and then adding a small amount of acetic acid solution to adjust the pH to 4-6.

2. A composite grouting reinforcement material for mining according to claim 1, characterized in that: The polyether polyol has a hydroxyl value of 150 to 550 mgKOH / g, a functionality of 2 to 3, and a viscosity of 250 to 600 mPa·s / 25°C.

3. A composite grouting reinforcement material for mining according to claim 1, characterized in that: The content of isocyanate in the isocyanate is 30% to 32%, and the viscosity is 150 to 450 mPa·s / 25°C.

4. A composite grouting reinforcement material for mining according to claim 1, characterized in that: The flame retardant includes one or more of tris(2-chloropropyl) phosphate, tris(2-chloroethyl) phosphate, triethyl phosphate, triphenyl phosphate, and tricresyl phosphate.

5. The composite grouting reinforcement material for mining according to claim 1, characterized in that: The catalyst is selected from one of dibutyltin dilaurate, lead octoate, stannous octoate, bismuth isooctanoate and zinc isooctanoate.

6. A composite grouting reinforcement material for mining according to claim 1, characterized in that: The anti-settling dispersant is selected from one or more of polyethylene wax, castor oil derivatives, polyamide modified alkyd resin, polyurethane modified alkyd resin, polymer carboxylic acid and silicone copolymer, and modified polyurea thickener.

7. A method for preparing the composite grouting reinforcement material for mining according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, pretreating fly ash to obtain modified fly ash; S2, adding the raw materials of component A to the reactor in sequence, stirring and dispersing them evenly under nitrogen protection, and maintaining the vacuum degree for a first preset time; adding the raw materials of component B to the reactor in sequence, stirring and dispersing them evenly under nitrogen protection, and maintaining the vacuum degree for a second preset time; S3, mixing the evenly dispersed component A and component B according to a preset volume ratio to obtain the composite grouting reinforcement material for mining.

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