New type of overburden separation grouting material for mine and preparation method thereof

Abstract

The present application relates to the technical field of grouting material, in particular to a new type of mine overburden separation layer grouting material and a preparation method thereof, comprising the following steps: S1. Preparation of modified dry desulfurization by-product; S2. The modified dry desulfurization by-product, fly ash and modified high-efficiency additive are sent into an open-circuit superfine ball mill for ball milling to obtain modified powder; S3. The modified powder is mixed with a performance modifier, and stirred for 3-5 min to finally obtain the new type of mine overburden separation layer grouting material. The synergistic effect of the modified dry desulfurization by-product, the modified high-efficiency additive and the performance modifier makes the new type of mine overburden separation layer grouting material have the advantages of good thixotropy, strong suspension stability, high fluidity, low water separation rate and the like, which is more conducive to grouting construction, and under the process cooperation of superfine grinding, the slurry is ensured not to block the pipe and not to separate when injected at high pressure, and efficient grouting is realized.

Description

Technical Field

[0001] This invention relates to the field of grouting materials technology, specifically to a novel grouting material for mining overburden separation and its preparation method. Background Technology

[0002] With the large-scale and high-intensity mining of coal resources, problems such as surface subsidence, ecological degradation, and damage to buildings and railways in mining areas have become increasingly prominent, and the contradiction between resource development and environmental protection has become increasingly acute. Overburden separation grouting technology, as an effective means of controlling surface subsidence, effectively reduces the subsidence space of the overlying strata by injecting grout material into the space created by mining, thereby limiting the movement of the overlying strata and surface subsidence. It has been widely used in mining areas in central and eastern my country. This technology has minimal interference with underground coal mining operations and can achieve green coal mining and solid waste resource utilization, and is being continuously researched and promoted. Regarding overburden separation grouting materials, fly ash is currently the preferred material, with coal gangue powder as an important substitute, supplemented by auxiliary materials such as coal slime and loess. However, existing grouting materials all have varying degrees of defects in practical applications: (1) The particle size distribution and fineness of fly ash are highly unstable due to factors such as the type of power plant boiler and the source of coal. The physicochemical properties of different batches of fly ash vary greatly, making it difficult to ensure the uniformity of grouting materials. In addition, fly ash itself has a certain degree of hydrophobicity, which makes it easy to agglomerate and precipitate in grout. The prepared grouting slurry is prone to sedimentation and stratification, which seriously affects the suspension stability and grouting effect of the slurry. Studies have shown that the fluidity and water separation rate of grouting slurry change significantly with the amount of fly ash added. Fly ash-based grout is prone to bleeding water under the action of formation pressure, which leads to a decrease in filling efficiency.

[0003] (2) Coal gangue has a complex composition, high carbon content, and high hardness. When used as a grouting material for overburden separation, it needs to undergo processing steps such as crushing and grinding. Currently, coal gangue slurry preparation mostly adopts wet grinding technology, which involves large equipment investment and high energy consumption, resulting in poor economic efficiency when used for coal mine overburden separation grouting. At the same time, coal gangue often contains harmful components such as pyrite, which may generate acidic wastewater after grouting and filling, posing a risk of secondary pollution.

[0004] (3) Coal slime, as a by-product of coal washing, has a moisture content of over 30%, making transportation and storage extremely inconvenient. It is also prone to freezing in winter, which seriously affects the continuity and stability of grouting construction. Even after dewatering, coal slime has low activity and insufficient cementing properties, making it difficult to use as a grouting material on its own.

[0005] (4) Loess is a non-metallic mineral resource. Its mining is subject to multiple legal constraints such as the Mineral Resources Law and the Land Management Law. Mining enterprises face increasing policy and cost pressures in the legal acquisition of loess. The route of relying on loess as grouting material is gradually becoming unfeasible.

[0006] In addition, as a byproduct of the dry desulfurization process, the dry desulfurization byproduct has the characteristics of fine particle size, alkalinity and calcium sulfite content. However, its composition is greatly affected by the source of flue gas, operating conditions and lime quality. When used directly as grouting material, it has problems such as obvious retardation effect of calcium sulfite and unstable activity, which greatly limits its large-scale utilization in the grouting field.

[0007] In summary, existing grouting materials for overburden separation generally suffer from problems such as limited raw material sources, unstable performance, easy slurry separation and bleeding, and high cost. There is an urgent need to develop a new type of grouting material with widely available raw materials, excellent grout performance, convenient construction, and environmental friendliness. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a new type of grouting material for mining overburden separation and its preparation method.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a novel overburden separation grouting material for mining includes the following preparation steps: S1. Preparation of modified dry desulfurization byproducts: S11. By weight, mix 90-100 parts of dry desulfurization byproduct (a mixture of sodium sulfite, sodium sulfate and sodium carbonate) with 1-3 parts of triethanolamine, 0.5-1 parts of citric acid and 140-150 parts of water until a paste is formed. S12. Slowly add 5-8 parts of hydrogen peroxide to the paste obtained in step S11, and stir the mixture at 300-400 r / min at 50-60℃ for 60-90 min. S13. Add 3-5 parts of sodium silicate and 2-4 parts of aluminum sulfate to the product after the reaction in step S12, continue stirring at a speed of 300-400 r / min for 25-30 min, dry at 100-105℃ to constant weight, pulverize and pass through a 200-mesh sieve to obtain the modified dry desulfurization byproduct. S2. Take 70-90 parts of the modified dry desulfurization byproduct obtained in step S1, 10-15 parts of fly ash, and 1-5 parts of modified high-efficiency additives and put them into an open-circuit ultrafine ball mill and ball mill for 30-90 minutes to obtain modified powder. S3. Mix the modified powder obtained in step S2 with 80-120 parts of performance modifier and stir at 800-1000 r / min for 3-5 min to finally obtain a new type of mining overburden separation grouting material.

[0010] Preferably, the preparation of the modified high-efficiency admixture includes the following steps: S21. By weight, add 8-10 parts of hydroxypropyl methylcellulose, 3-5 parts of xanthan gum, and 15-20 parts of magnesium aluminum silicate to 35-40 parts of water, and stir at 40-50°C until completely dissolved; S22. Add 25-30 parts of polycarboxylate superplasticizer, 5-8 parts of sodium tripolyphosphate, 2-4 parts of polyacrylamide, 1-3 parts of sodium dodecyl sulfate, and 6-8 parts of redispersible latex powder to the solution obtained in step S21, and continue stirring for 15-20 minutes. S23. Spray dry the mixture obtained in step S22 to finally obtain the modified high-efficiency admixture.

[0011] Preferably, the preparation of the performance modifier includes the following steps: S31. By weight, mix 180-200 parts water with 6-10 parts polyvinyl alcohol and stir at 400-500 r / min at 80-90℃ until completely dissolved; S32. Add 16-20 parts sodium silicate, 3-5 parts triethanolamine, 6-10 parts aluminum sulfate, and 1-3 parts citric acid to the solution obtained in step S31, cool to 40-50℃ and continue stirring for 10-15 minutes; S33. Add 0.6-1 part of polydimethylsiloxane to the solution obtained in step S32, stir at 100-150 r / min for 5-8 min, and then pass through a 200 mesh sieve to finally obtain the performance modifier.

[0012] Preferably, the mass concentration of hydrogen peroxide in step S12 is 30-35%.

[0013] Preferably, in step S2, the grinding media of the ultrafine ball mill are zirconia balls or steel balls, the ball-to-material ratio is 4:1, and the rotation speed is 35-40 r / min.

[0014] Preferably, the stirring speed in step S21 is 800-1000 r / min.

[0015] Preferably, in step S23, the inlet air temperature of the spray drying is 180-190°C and the outlet air temperature is 70-80°C.

[0016] A novel grouting material for mining overburden separation is prepared by the above-mentioned method.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes the synergistic effect of modified dry desulfurization byproducts, modified high-efficiency additives, and performance modifiers to produce a novel mining overburden separation grouting material with advantages such as good thixotropic properties, strong suspension stability, high fluidity, and low water separation rate. This is more conducive to grouting construction. With the support of ultrafine grinding technology, it ensures that the grout does not clog pipes or segregate during high-pressure injection, thus achieving efficient grouting.

[0018] 2. Due to its ultrafine properties, the specific surface area of ​​the material in this invention reaches 500m². 2 At / kg, under the same conditions, it can penetrate finer fissures compared to fly ash, thus resulting in better injectability of the grout. Simultaneously, this invention achieves comprehensive utilization of industrial solid waste, and closed transportation and storage reduce fugitive dust emissions. Because the product is factory-produced, the homogenization effect is better, and the product performance is more stable and reliable, providing convenience for on-site grouting. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation process of the novel overburden separation grouting material for mining according to the present invention. Figure 2 This is a flow chart of the preparation process of the modified high-efficiency admixture of the present invention; Figure 3 This is a process flow diagram for preparing the performance modifier of the present invention; Figure 4 The X-ray diffraction spectrum of the novel mining overburden separation grouting material obtained in Example 1 of this invention; Figure 5 The X-ray diffraction spectrum of the novel mining overburden separation grouting material obtained in Example 2 of this invention is shown. Detailed Implementation

[0020] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-5 The present invention provides a technical solution: Example 1 Preparation method of novel overburden separation grouting material for mining: Before preparing the new type of mining overburden delamination grouting material, the following steps are taken: Preparation of modified high-efficiency admixtures and performance modifiers is performed: The preparation of modified high-efficiency admixtures includes the following steps: S21. Add 8g hydroxypropyl methylcellulose, 3g xanthan gum, and 15g magnesium aluminum silicate to 35g water, and stir at 800r / min at 40℃ until completely dissolved; S22. Add 25g of polycarboxylate superplasticizer, 5g of sodium tripolyphosphate, 2g of polyacrylamide, 1g of sodium dodecyl sulfate, and 6g of redispersible latex powder to the solution obtained in step S21, and continue stirring for 15 minutes; S23. Spray dry the mixture obtained in step S22 (inlet air temperature 180℃, outlet air temperature 70℃) to finally obtain the modified high-efficiency admixture.

[0022] The preparation of performance modifiers includes the following steps: S31. Mix 180g of water with 6g of polyvinyl alcohol and stir at 400r / min at 80℃ until completely dissolved; S32. Add 16g sodium silicate, 3g triethanolamine, 6g aluminum sulfate and 1g citric acid to the solution obtained in step S31, cool to 40℃ and continue stirring for 10min; S33. Add 0.6g of polydimethylsiloxane to the solution obtained in step S32, stir at 100r / min for 5min, and then pass through a 200-mesh sieve to finally obtain the performance modifier.

[0023] S1. Preparation of modified dry desulfurization byproducts: S11. Mix 90g of dry desulfurization byproduct with 1g of triethanolamine, 0.5g of citric acid and 140g of water until a paste is formed; S12. Slowly add 5g of 30% hydrogen peroxide to the paste obtained in step S11, and stir the mixture at 300r / min at 50℃ for 60min. S13. Add 3g of sodium silicate and 2g of aluminum sulfate to the product after the reaction in step S12, continue stirring at 300r / min for 25min, dry at 100℃ to constant weight, pulverize and pass through a 200-mesh sieve to obtain the modified dry desulfurization byproduct. S2. Take 70g of the modified dry desulfurization byproduct obtained in step S1, 10g of fly ash, and 1g of modified high-efficiency additive and feed them into an open-circuit ultrafine ball mill (the grinding media is zirconia balls or steel balls, the ball-to-material ratio is 4:1, and the rotation speed is 35r / min) and ball mill for 30min to obtain modified powder. S3. Mix the modified powder obtained in step S2 with 80g of performance modifier and stir at 800r / min for 3min to finally obtain a new type of mining overburden separation grouting material.

[0024] Example 2 Preparation method of novel overburden separation grouting material for mining: Before preparing the new type of mining overburden delamination grouting material, the following steps are taken: Preparation of modified high-efficiency admixtures and performance modifiers is performed: The preparation of modified high-efficiency admixtures includes the following steps: S21. Add 10g hydroxypropyl methylcellulose, 5g xanthan gum, and 20g magnesium aluminum silicate to 40g water, and stir at 1000r / min at 50℃ until completely dissolved; S22. Add 30g of polycarboxylate superplasticizer, 8g of sodium tripolyphosphate, 4g of polyacrylamide, 3g of sodium dodecyl sulfate, and 8g of redispersible latex powder to the solution obtained in step S21, and continue stirring for 20 minutes; S23. The mixture obtained in step S22 is spray-dried (inlet air temperature 190℃, outlet air temperature 80℃) to finally obtain the modified high-efficiency admixture.

[0025] The preparation of performance modifiers includes the following steps: S31. Mix 200g of water with 10g of polyvinyl alcohol and stir at 500r / min at 90℃ until completely dissolved; S32. Add 20g sodium silicate, 5g triethanolamine, 10g aluminum sulfate and 3g citric acid to the solution obtained in step S31, cool to 50℃ and continue stirring for 15min; S33. Add 1g of polydimethylsiloxane to the solution obtained in step S32, stir at 150r / min for 8min, and then pass through a 200-mesh sieve to finally obtain the performance modifier.

[0026] S1. Preparation of modified dry desulfurization byproducts: S11. Mix 100g of dry desulfurization byproduct with 3g of triethanolamine, 1g of citric acid and 150g of water until a paste is formed. S12. Slowly add 8g of 35% hydrogen peroxide dropwise to the paste obtained in step S11, and stir the mixture at 400r / min at 60℃ for 90min. S13. Add 5g of sodium silicate and 4g of aluminum sulfate to the product after the reaction in step S12, continue stirring at 400r / min for 30min, dry at 105℃ to constant weight, pulverize and pass through a 200-mesh sieve to obtain the modified dry desulfurization byproduct. S2. Take 90g of the modified dry desulfurization byproduct obtained in step S1, 15g of fly ash, and 5g of modified high-efficiency additives and put them into an open-circuit ultrafine ball mill (the grinding media is zirconia balls or steel balls, the ball-to-material ratio is 4:1, and the rotation speed is 40r / min) and ball mill for 90min to obtain modified powder. S3. Mix the modified powder obtained in step S2 with 120g of performance modifier and stir at 1000r / min for 5min to finally obtain a new type of mining overburden separation grouting material.

[0027] Example 3 Preparation method of novel overburden separation grouting material for mining: Before preparing the new type of mining overburden delamination grouting material, the following steps are taken: Preparation of modified high-efficiency admixtures and performance modifiers is performed: The preparation of modified high-efficiency admixtures includes the following steps: S21. Add 9g hydroxypropyl methylcellulose, 4g xanthan gum, and 17g magnesium aluminum silicate to 37g water, and stir at 900r / min at 45℃ until completely dissolved; S22. Add 27g of polycarboxylate superplasticizer, 6g of sodium tripolyphosphate, 3g of polyacrylamide, 2g of sodium dodecyl sulfate, and 7g of redispersible latex powder to the solution obtained in step S21, and continue stirring for 17 minutes; S23. The mixture obtained in step S22 is spray-dried (inlet air temperature 185℃, outlet air temperature 75℃) to finally obtain the modified high-efficiency admixture.

[0028] The preparation of performance modifiers includes the following steps: S31. Mix 185g of water with 7g of polyvinyl alcohol and stir at 450r / min at 83℃ until completely dissolved; S32. Add 18g sodium silicate, 4g triethanolamine, 8g aluminum sulfate and 2g citric acid to the solution obtained in step S31, cool to 45℃ and continue stirring for 12min; S33. Add 0.8g of polydimethylsiloxane to the solution obtained in step S32, stir at 120r / min for 6min, and then pass through a 200-mesh sieve to finally obtain the performance modifier.

[0029] S1. Preparation of modified dry desulfurization byproducts: S11. Mix 95g of dry desulfurization byproduct with 2g of triethanolamine, 0.7g of citric acid and 145g of water until a paste is formed; S12. Slowly add 6g of 32% hydrogen peroxide dropwise to the paste obtained in step S11, and stir the mixture at 350r / min at 55℃ for 70min. S13. Add 4g of sodium silicate and 3g of aluminum sulfate to the product after the reaction in step S12, continue stirring at 320r / min for 27min, dry at 103℃ to constant weight, pulverize and pass through a 200-mesh sieve to obtain the modified dry desulfurization byproduct. S2. Take 80g of the modified dry desulfurization byproduct obtained in step S1, 12g of fly ash, and 2g of modified high-efficiency additives and feed them into an open-circuit ultrafine ball mill (the grinding media is zirconia balls or steel balls, the ball-to-material ratio is 4:1, and the rotation speed is 37r / min) and ball mill for 50min to obtain modified powder. S3. Mix the modified powder obtained in step S2 with 100g of performance modifier and stir at 900r / min for 4min to finally obtain a new type of mining overburden separation grouting material.

[0030] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the modified dry desulfurization byproduct is replaced with the ordinary dry desulfurization byproduct in this comparative example. The remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0031] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the performance modifier is replaced with water in this comparative example, while the other steps are exactly the same in Comparative Example 2 and Example 1.

[0032] Performance testing: Appendix Figure 4 and attached Figure 5 The X-ray diffraction spectra of the novel mining overburden delamination grouting materials obtained in Examples 1 and 2 of this invention are shown below. The vertical axis, Intensity (Counts), represents the diffraction peak count, indicating the intensity of the crystal diffraction signal. Higher peaks correspond to higher crystalline phase content / crystallinity. The horizontal axis, 2θ, ranges from 10° to 90°. The figures show a continuous low baseline at the bottom of the spectrum, indicating the presence of amorphous components in the sample. The strong peaks around 28.5-29.6° are the core feature of this spectrum, indicating the highest intensity in this region and the largest contribution of the corresponding crystalline phase. For the novel mining overburden delamination grouting materials obtained in Examples 1 and 2, this region is likely composed of modified dry desulfurization byproducts. The peak combinations near 18.3°, 34.3°, 47.0°, and 51.0° indicate the possible presence of Ca(OH)₂ in the sample. Ca(OH)₂ provides an alkaline environment, promoting the dissolution of active Si and Al components in the ash and creating conditions for the subsequent formation of CSH, CASH, or ettringite-like products. However, the Ca(OH)₂ peak intensity is not particularly dominant, suggesting it may not be the only main phase. Furthermore, if the sample comes into contact with CO₂ during storage, sample preparation, or curing, some Ca(OH)₂ may have carbonized into CaCO₃. Therefore, the figure shows that the crystal phase composition of the novel mining overburden delamination grouting materials obtained in Examples 1 and 2 should be dominated by calcium-based desulfurization products.

[0033] The flowability of the novel mining overburden separation grouting materials obtained in Examples 1-3 and Comparative Examples 1-2 was tested according to GB / T 50448-2015 "Technical Specification for Application of Cement-Based Grouting Materials". Using the truncated cone mold method, the mixed grout was injected into the center of the truncated cone mold, the top was leveled, and the mold was quickly lifted vertically upwards. The grout flowed freely under gravity until it stopped. The maximum diffusion diameter in two mutually perpendicular directions was measured, and the arithmetic mean was taken. The initial flowability (tested immediately after mixing) and the flowability after 30 minutes were tested respectively.

[0034] According to NB / T 10738-2021 "Test Method for Compaction and Bleeding Characteristics of Grouting Filling for Overburden Separation in Mining", the water separation rate of the novel overburden separation grouting materials obtained in Examples 1-3 and Comparative Examples 1-2 was tested. Using the graduated cylinder static method, the uniformly stirred grout was poured into a 100mL graduated cylinder, and the total volume and mass m0 of the grout were accurately recorded. After standing for 2 hours, the water that had separated from the top was sucked up with a pipette, and the mass of the separated water m1 was weighed. The water separation rate R was calculated as R = (m1 / m0) × 100%.

[0035] The water separation rate of the novel mining overburden separation grouting materials obtained in Examples 1-3 and Comparative Examples 1-2 was tested using the sedimentation method (a general method for evaluating grout stability). The density difference method was employed. The uniformly stirred grout was injected into a 250 mL graduated cylinder and allowed to stand for 24 hours. Samples were taken from 2 cm below the liquid surface and 2 cm above the bottom using a pipette. The densities of the upper and lower grout layers were determined using the hydrostatic bottle method, and the density difference was calculated.

[0036] The setting time of the novel mining overburden separation grouting materials obtained in Examples 1-3 and Comparative Examples 1-2 was tested according to GB / T 1346-2011 "Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement". The mixed grout was poured into a circular mold, the surface was leveled, and the mold was placed in a curing chamber for curing. The initial setting time was recorded when the test needle sank 4 mm from the bottom plate; the final setting time was recorded when the test needle sank 0.5 mm into the grout. The final results are shown in Table 1 below. Table 1 Performance Test Results As shown in Table 1, the novel overburden delamination grouting materials obtained in Examples 1-3 are superior to the comparative examples in all performance aspects. The fluidity data indicates that the synergistic effect of modified dry desulfurization byproducts, modified high-efficiency additives, and performance modifiers effectively reduces the surface tension of the slurry, improves its dispersibility, and further optimizes its rheological properties. The synergistic effect of these three agents enhances the water retention capacity of the slurry, improves the surface charge and hydrophilicity of particles, reduces agglomeration and sedimentation, significantly reduces the water separation rate, and ensures that the slurry remains uniform and stable within 24 hours. The appropriate setting time ensures sufficient construction operation time (initial setting ≥ 60 min) while avoiding excessive slow setting that could affect project progress. This invention successfully prepared a novel overburden delamination grouting material with high fluidity, low water separation rate, and excellent suspension stability. All three examples meet the performance requirements of overburden delamination grouting projects. This material effectively solves the problems of easy stratification and water leakage, and unstable performance of existing grouting materials, providing reliable engineering material support for overburden delamination grouting sedimentation reduction technology.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a novel overburden separation grouting material for mining, characterized in that, The preparation steps include the following: S1. Preparation of modified dry desulfurization byproducts: S11. By weight, mix 90-100 parts of dry desulfurization byproduct with 1-3 parts of triethanolamine, 0.5-1 parts of citric acid and 140-150 parts of water until a paste is formed; S12. Slowly add 5-8 parts of hydrogen peroxide to the paste obtained in step S11, and stir the mixture at 300-400 r / min at 50-60℃ for 60-90 min. S13. Add 3-5 parts of sodium silicate and 2-4 parts of aluminum sulfate to the product after the reaction in step S12, continue stirring at a speed of 300-400 r / min for 25-30 min, dry at 100-105℃ to constant weight, pulverize and pass through a 200-mesh sieve to obtain the modified dry desulfurization byproduct. S2. Take 70-90 parts of the modified dry desulfurization byproduct obtained in step S1, 10-15 parts of fly ash, and 1-5 parts of modified high-efficiency additives and put them into an open-circuit ultrafine ball mill and ball mill for 30-90 minutes to obtain modified powder. S3. Mix the modified powder obtained in step S2 with 80-120 parts of performance modifier and stir at 800-1000 r / min for 3-5 min to finally obtain a new type of mining overburden separation grouting material.

2. The preparation method of the novel mining overburden separation grouting material according to claim 1, characterized in that, The preparation of the modified high-efficiency admixture includes the following steps: S21. By weight, add 8-10 parts of hydroxypropyl methylcellulose, 3-5 parts of xanthan gum, and 15-20 parts of magnesium aluminum silicate to 35-40 parts of water, and stir at 40-50°C until completely dissolved; S22. Add 25-30 parts of polycarboxylate superplasticizer, 5-8 parts of sodium tripolyphosphate, 2-4 parts of polyacrylamide, 1-3 parts of sodium dodecyl sulfate, and 6-8 parts of redispersible latex powder to the solution obtained in step S21, and continue stirring for 15-20 minutes. S23. Spray dry the mixture obtained in step S22 to finally obtain the modified high-efficiency admixture.

3. The preparation method of the novel mining overburden separation grouting material according to claim 1, characterized in that, The preparation of the performance modifier includes the following steps: S31. By weight, mix 180-200 parts water with 6-10 parts polyvinyl alcohol and stir at 400-500 r / min at 80-90℃ until completely dissolved; S32. Add 16-20 parts sodium silicate, 3-5 parts triethanolamine, 6-10 parts aluminum sulfate, and 1-3 parts citric acid to the solution obtained in step S31, cool to 40-50℃ and continue stirring for 10-15 minutes; S33. Add 0.6-1 part of polydimethylsiloxane to the solution obtained in step S32, stir at 100-150 r / min for 5-8 min, and then pass through a 200 mesh sieve to finally obtain the performance modifier.

4. The preparation method of the novel mining overburden separation grouting material according to claim 1, characterized in that, The mass concentration of hydrogen peroxide in step S12 is 30-35%.

5. The preparation method of the novel mining overburden separation grouting material according to claim 1, characterized in that, In step S2, the grinding media of the ultrafine ball mill are zirconia balls or steel balls, the ball-to-material ratio is 4:1, and the rotation speed is 35-40 r / min.

6. The preparation method of the novel mining overburden separation grouting material according to claim 2, characterized in that, The stirring speed in step S21 is 800-1000 r / min.

7. The preparation method of the novel mining overburden separation grouting material according to claim 1, characterized in that, In step S23, the inlet air temperature of the spray dryer is 180-190℃ and the outlet air temperature is 70-80℃.

8. A novel grouting material for exfoliating overburden in mining, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

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