Mine filling material based on fly ash solid waste and preparation method thereof

Abstract

The invention relates to the field of filling materials, in particular to a mine filling material based on fly ash solid waste and a preparation method of the mine filling material, and aims at solving the problems that an existing filling material is poor in strength and durability and difficult to meet the special requirements of mine goaf filling. According to the preparation method, the industrial solid waste fly ash is fully utilized as a main raw material, so that the influence of large-amount stacking of fly ash on the environment and the damage of toxic heavy metals in fly ash on soil are reduced, land resources are saved, meanwhile, the cost of the mine filling material is greatly reduced, large-scale resource utilization of waste is realized, and the economic benefit is increased. The mechanical property and the waterproof property of the mine filling material can be greatly improved by adding the epoxy long-chain modified whisker and the polyfluorine coupling agent, the mine goaf can be effectively filled, the safety production of the mine is guaranteed, and the mine filling requirement is met; and powerful support is provided for sustainable development of the mining industry.

Description

Technical Field

[0001] The invention relates to the field of filling materials, and in particular to a mine filling material based on fly ash solid waste and a preparation method thereof. Background Art

[0002] As global mining activities continue to heat up, the task of backfilling goafs has become increasingly arduous. Existing mine filling materials are mainly natural materials such as soil, stone, and sand, which have relatively simple properties and are difficult to meet the special requirements of different mine fillings. In addition, the resources of natural materials are limited, and the costs of mining and transportation are high. Therefore, it is of great significance to explore low-cost and environmentally friendly mine filling materials. Fly ash, as a solid waste generated in large quantities in industries such as thermal power generation, has an astonishing annual emission. For a long time, its stacking has occupied vast tracts of land, and the heavy metals and harmful substances it contains have posed a serious threat to the ecology of soil and water bodies. Although there have been some explorations on the use of fly ash to prepare mine filling materials, the existing fly ash mine filling material products still have significant shortcomings in terms of strengthening mechanical properties and improving anti-corrosion capabilities, resulting in poor strength and durability of the filling materials, which are difficult to meet the special requirements of mine goaf filling. Summary of the invention

[0003] In order to overcome the above technical problems, the purpose of the present invention is to provide a mine filling material based on fly ash solid waste and a preparation method thereof, which solves the problem that the existing filling materials have poor strength and durability and are difficult to meet the special requirements of mine goaf filling.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A mine filling material based on fly ash solid waste comprises the following components in parts by weight: 30-40 parts of cement, 70-80 parts of fly ash, 15-21 parts of kaolin, 7-11 parts of water glass, 2-6 parts of sodium hydroxide, 1-3 parts of water reducer, 1.3-6.1 parts of epoxy long chain modified whisker, 0.8-3.6 parts of polyfluoride linker and 40-50 parts of water; The epoxy long-chain modified whiskers are obtained by modifying silicon carbide whiskers with diene fatty acids and then epoxidizing them; The polyfluorinated linking agent is obtained by reacting a hydroxy polyfluorinated intermediate with epichlorohydrin.

[0005] The epoxy long-chain modified whisker is prepared by the following steps: Step a1: add glyceryl monostearate, maleic anhydride and anhydrous toluene to a three-necked flask equipped with a stirrer and a thermometer, stir and react for 15-20 minutes at a temperature of 25-30° C. and a stirring rate of 300-400 r / min, then add p-toluenesulfonic acid and continue stirring and reacting for 9-10 hours at a temperature of 90-95° C. After the reaction is completed, the reaction product is cooled to room temperature, then added to distilled water, then allowed to stand for stratification, the organic phase is dried over anhydrous magnesium sulfate, then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a diene fatty acid; Step a2: Add silicon carbide whiskers and anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer, stir and react for 30-50 minutes at a temperature of 25-30° C. and a stirring rate of 300-400 r / min, then add diene fatty acid and continue stirring and reacting for 3-4 hours at a temperature of 80-85° C. After the reaction is completed, cool the reaction product to room temperature, then vacuum filter, wash the filter cake with distilled water for 3-5 times, then place it in a vacuum drying oven, and dry it at a temperature of 50-55° C. for 2-3 hours to obtain diene long-chain modified whiskers; Step a3: Add the olefin long-chain modified whiskers, formic acid and hydrogen peroxide into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 20-30 minutes at a temperature of 10-15°C and a stirring rate of 300-400r / min, then heat to 50-55°C and continue stirring and reacting for 3-4 hours. After the reaction is completed, cool the reaction product to room temperature, then vacuum filter, wash the filter cake with distilled water for 3-5 times, then place it in a vacuum drying oven, and dry it at a temperature of 50-55°C for 4-5 hours to obtain epoxy long-chain modified whiskers.

[0006] As a further solution of the present invention: the usage ratio of the glyceryl monostearate, maleic anhydride, anhydrous toluene and p-toluenesulfonic acid in step a1 is 10 mmol: 22-25 mmol: 40-50 mL: 0.04-0.08 g.

[0007] As a further solution of the present invention: the usage ratio of the silicon carbide whisker, anhydrous ethanol and diene fatty acid in step a2 is 5g:50-60mL:2-7g.

[0008] As a further solution of the present invention: the silicon carbide whisker in step a2 is a silicon carbide whisker with a diameter of 2-5 μm and a length of 50-100 μm.

[0009] As a further solution of the present invention: the usage ratio of the alkenyl long-chain modified whisker, formic acid and hydrogen peroxide in step a3 is 5g:8-10g:30-35mL.

[0010] As a further solution of the present invention: the mass fraction of the hydrogen peroxide in step a3 is 30-35%.

[0011] As a further solution of the present invention: the diameter of the epoxy long-chain modified whiskers in step a3 is 2.6-5.9 μm and the length is 62-117 μm.

[0012] As a further solution of the present invention: the polyfluoro linker is prepared by the following steps: Step b1: Add 2,2-dihydroxymethylpropionic acid, octafluoropentanol, p-toluenesulfonic acid and anhydrous toluene into a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, introduce nitrogen protection, stir and react for 10-15 minutes at a temperature of 15-20° C. and a stirring rate of 300-400 r / min, then heat to reflux and continue stirring and reacting for 3-4 hours. After the reaction is completed, cool the reaction product to room temperature, then add it to a sodium hydroxide solution, then stand and stratify, dry the organic phase with anhydrous magnesium sulfate, then vacuum filter, and rotary evaporate the filtrate to remove the solvent to obtain a hydroxy polyfluoro intermediate; Step b2: Add the hydroxypolyfluoro intermediate, epichlorohydrin, tetrabutylammonium bromide and cyclohexane to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, introduce nitrogen protection, stir the reaction for 10-15 minutes at a temperature of 25-30°C and a stirring rate of 300-400r / min, then raise the temperature to reflux and continue to stir the reaction for 2-3 hours, then add sodium hydroxide solution and continue to stir the reaction for 5-6 hours under the condition of cooling to 50-55°C. After the reaction is completed, the reaction product is cooled to room temperature, then washed with distilled water 3-5 times, then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a polyfluoro coupling agent.

[0013] As a further solution of the present invention: the usage ratio of the 2,2-dihydroxymethylpropionic acid, octafluoropentanol, p-toluenesulfonic acid and anhydrous toluene in step b1 is 10 mmol: 10 mmol: 0.01-0.03 g: 40-50 mL.

[0014] As a further solution of the present invention: the mass fraction of the sodium hydroxide solution in step b1 is 3-5%.

[0015] As a further scheme of the present invention: the usage ratio of the hydroxypolyfluoro intermediate, epichlorohydrin, tetrabutylammonium bromide, cyclohexane and sodium hydroxide solution in step b2 is 10mmol:100-120mmol:0.05-0.15g:50-60mL:25-30mL.

[0016] As a further solution of the present invention: the mass fraction of the sodium hydroxide solution in step b2 is 40-45%.

[0017] As a further solution of the present invention: a method for preparing a mine filling material based on fly ash solid waste comprises the following steps: Step 1: Weigh 30-40 parts of cement, 70-80 parts of fly ash, 15-21 parts of kaolin, 7-11 parts of water glass, 2-6 parts of sodium hydroxide, 1-3 parts of water reducer, 1.3-6.1 parts of epoxy long-chain modified whisker, 0.8-3.6 parts of polyfluoride linker and 40-50 parts of water according to weight parts, and set aside; Step 2: Add cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whisker, polyfluorine linking agent and water into a mixer and mix them evenly to obtain a mine filling material based on fly ash solid waste.

[0018] As a further solution of the present invention: the cement is P.0 42.5 ordinary Portland cement; the water reducer is polycarboxylate water reducer MT 3800.

[0019] Beneficial effects of the present invention: The invention discloses a mine filling material based on fly ash solid waste and a preparation method thereof. The mine filling material based on fly ash solid waste is obtained by adding cement, fly ash, kaolin, water glass, sodium hydroxide, a water reducer, epoxy long-chain modified whiskers, a polyfluoro linker and water into a mixer and stirring evenly. The preparation method makes full use of fly ash, an industrial solid waste, as a main raw material, reduces the environmental impact caused by large-scale storage of fly ash and the damage to soil by toxic heavy metals in fly ash, saves land resources, and greatly reduces the cost of mine filling materials, realizes large-scale resource utilization of waste, has significant environmental and economic benefits, and can greatly improve the mechanical properties and waterproof properties of the mine filling material by adding epoxy long-chain modified whiskers and polyfluoro linkers thereto, can effectively fill mine goafs, ensure mine safety production, meet mine filling requirements, and provide strong support for the sustainable development of the mining industry.

[0020] In the process of preparing mine filling materials based on fly ash solid waste, epoxy long-chain modified whiskers are added. First, monostearate glyceryl and maleic anhydride are reacted. The hydroxyl group on the monostearate reacts with the anhydride group on the maleic anhydride, and alkenyl and carboxyl groups are introduced at the same time to obtain dienyl fatty acids. Then, the dienyl fatty acids are used to modify the silicon carbide whiskers. The dienyl fatty acids react with the hydroxyl groups on the silicon carbide whiskers using carboxyl groups, thereby grafting alkenyl long carbon chains onto the silicon carbide whiskers to obtain alkenyl long-chain modified whiskers. Then, the alkenyl groups on the alkenyl long-chain modified whiskers are epoxidized by the Prilezhaev method and converted into epoxy groups to obtain epoxy long-chain modified whiskers. The silicon carbide whiskers have high strength, high modulus and excellent heat resistance. The excellent properties can greatly enhance the mechanical properties of mine filling materials, and when the filling material is subjected to external force, the silicon carbide whiskers can form bridges between cracks to hinder the further development of the cracks, thereby improving the toughness of the material. After the silicon carbide whiskers are modified, the surface properties of the silicon carbide whiskers are improved, so that the silicon carbide whiskers are evenly dispersed in the filling material system to avoid agglomeration, so that they can better combine with the matrix material and give full play to their high strength and high modulus characteristics, providing excellent mechanical enhancement effects for the material, and the introduced epoxy groups can chemically bond with other components, thereby improving the interfacial bonding strength, strengthening the interfacial bonding force bridging and pull-out effects, thereby improving the overall strength of the filling material.

[0021] In the process of preparing the mine filling material based on fly ash solid waste, a polyfluorinated linker is also added. First, 2,2-dihydroxymethylpropionic acid and octafluoropentanol are reacted, and the carboxyl group on the 2,2-dihydroxymethylpropionic acid and the hydroxyl group on the octafluoropentanol undergo an esterification reaction to obtain a hydroxy polyfluorinated intermediate. Then, the hydroxy polyfluorinated intermediate and epichlorohydrin react. After the ring opening and closing, the epichlorohydrin can introduce an epoxy group to the hydroxy polyfluorinated intermediate to obtain a polyfluorinated linker. The polyfluorinated linker can use the epoxy group on its molecular structure to react with various components of the fly ash of the mine filling material. The surface active sites are cross-linked to construct a three-dimensional network structure, which enables the material to work synergistically when subjected to stress, thereby improving the overall strength and stability of the material and playing an excellent buffering and toughening role. In addition, a large number of fluorine atoms, with their super electronegativity, form a dense fluoride protective layer on the surface of the material, which effectively blocks water, acid, alkali and other corrosive media in the mining environment, making it difficult for corrosive media to infiltrate and penetrate into the filling material, significantly enhancing the chemical stability and durability of the filling material, effectively protecting the matrix structure of the filling material, and extending the service life of the filling material. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Embodiment 1: This embodiment is a method for preparing a mine filling material based on fly ash solid waste, comprising the following steps: Step S1: 10 mmol of monostearate glyceryl, 22 mmol of maleic anhydride and 40 mL of anhydrous toluene are added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture is stirred for reaction at 25°C and a stirring rate of 300 r / min for 15 min, and then 0.04 g of p-toluenesulfonic acid is added and the mixture is heated to 90°C and the stirring reaction is continued for 9 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to distilled water, and then allowed to stand for stratification, and the organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a diene fatty acid; wherein the CAS number of monostearate glyceryl is 123-94-4; the CAS number of maleic anhydride is 108-31-6; and the CAS number of p-toluenesulfonic acid is 104-15-4; Step S2: adding 5 g of silicon carbide whiskers and 50 mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer, stirring the reaction for 30 min at a temperature of 25° C. and a stirring rate of 300 r / min, then adding 2 g of diene fatty acid and heating the mixture to 80° C. and continuing to stir the reaction for 3 h. After the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtered, the filter cake is washed with distilled water for 3 times, then placed in a vacuum drying oven, and dried at a temperature of 50° C. for 2 h to obtain an olefin long-chain modified whisker; wherein the silicon carbide whisker has a diameter of 2-5 μm and a length of 50-100 μm; Step S3: 5 g of olefin long-chain modified whiskers, 8 g of formic acid and 30 mL of 30% hydrogen peroxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred for reaction at a temperature of 10° C. and a stirring rate of 300 r / min for 20 min, and then heated to 50° C. and continued to stir for 3 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water for 3 times, and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 4 h to obtain epoxy long-chain modified whiskers; wherein the CAS number of formic acid is 64-18-6; Step S4: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol octafluoropentanol, 0.01 g p-toluenesulfonic acid and 40 mL anhydrous toluene are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 15° C. and a stirring rate of 300 r / min for 10 min, and then the mixture is heated to reflux and stirred for reaction for 3 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a 3% sodium hydroxide solution, and then allowed to stand for stratification. The organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a hydroxy polyfluoro intermediate; wherein the CAS number of 2,2-dihydroxymethylpropionic acid is 4767-03-7; the CAS number of octafluoropentanol is 355-80-6; and the CAS number of p-toluenesulfonic acid is 104-15-4; Step S5: 10 mmol of hydroxy polyfluoro intermediate, 100 mmol of epichlorohydrin, 0.05 g of tetrabutylammonium bromide and 50 mL of cyclohexane are added to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25° C. and a stirring rate of 300 r / min for 10 min, and then the mixture is heated to reflux and stirred for reaction for 2 h. Then 25 mL of a 40% sodium hydroxide solution is added and the mixture is cooled to 50° C. and stirred for reaction for 5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then washed with distilled water for 3 times, and then dried with anhydrous magnesium sulfate, and then vacuum filtered. The filtrate is rotary evaporated to remove the solvent to obtain a polyfluoro coupling agent; wherein the CAS number of epichlorohydrin is 106-89-8; the CAS number of tetrabutylammonium bromide is 1643-19-2; Step S6: weighing 30 kg of cement, 70 kg of fly ash, 15 kg of kaolin, 7 kg of water glass, 2 kg of sodium hydroxide, 1 kg of water reducer, 1.3 kg of epoxy long-chain modified whiskers, 0.8 kg of polyfluorine coupling agent and 40 kg of water for standby use; the diameter range of the epoxy long-chain modified whiskers used is 2.6-5.9 μm, and the length range is 62-117 μm; Step S7: adding cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whisker, polyfluorine linking agent and water into a mixer and stirring evenly to obtain a mine filling material based on fly ash solid waste.

[0024] Embodiment 2: This embodiment is a method for preparing a mine filling material based on fly ash solid waste, comprising the following steps: Step S1: 10 mmol of glyceryl monostearate, 24 mmol of maleic anhydride and 45 mL of anhydrous toluene are added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture is stirred for reaction at 28° C. and a stirring rate of 350 r / min for 18 min, and then 0.06 g of p-toluenesulfonic acid is added and the mixture is heated to 92° C. and the stirring reaction is continued for 9.5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to distilled water, and then allowed to stand for stratification, and the organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a diene fatty acid; wherein the CAS number of glyceryl monostearate is 123-94-4; the CAS number of maleic anhydride is 108-31-6; and the CAS number of p-toluenesulfonic acid is 104-15-4; Step S2: adding 5 g of silicon carbide whiskers and 55 mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer, stirring the reaction for 40 min at a temperature of 28° C. and a stirring rate of 350 r / min, then adding 4.5 g of diene fatty acid and heating the temperature to 82° C. and continuing to stir the reaction for 3.5 h. After the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtered, the filter cake is washed with distilled water 4 times, and then placed in a vacuum drying oven, and dried at a temperature of 52° C. for 2.5 h to obtain an olefin long-chain modified whisker; wherein the diameter of the silicon carbide whisker is 2-5 μm and the length is 50-100 μm; Step S3: 5 g of olefin long-chain modified whiskers, 9 g of formic acid and 32 mL of 32% hydrogen peroxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred for reaction at a temperature of 12° C. and a stirring rate of 350 r / min for 25 min, and then heated to 52° C. and continued to stir for 3.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water for 4 times, and then placed in a vacuum drying oven and dried at a temperature of 52° C. for 4.5 h to obtain epoxy long-chain modified whiskers; wherein the CAS number of formic acid is 64-18-6; Step S4: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol octafluoropentanol, 0.02 g p-toluenesulfonic acid and 45 mL anhydrous toluene are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The reaction is stirred for 12 minutes at a temperature of 18° C. and a stirring rate of 350 r / min, and then the temperature is raised to reflux and the stirring reaction is continued for 3.5 hours. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a sodium hydroxide solution with a mass fraction of 4%, and then allowed to stand for stratification. The organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a hydroxy polyfluoro intermediate; wherein the CAS number of 2,2-dihydroxymethylpropionic acid is 4767-03-7; the CAS number of octafluoropentanol is 355-80-6; and the CAS number of p-toluenesulfonic acid is 104-15-4; Step S5: 10mmol of hydroxy polyfluoro intermediate, 110mmol of epichlorohydrin, 0.1g of tetrabutylammonium bromide and 55mL of cyclohexane are added to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 28°C and a stirring rate of 350r / min for 12min, and then the mixture is heated to reflux and stirred for reaction for 2.5h. Then 28mL of a 42% sodium hydroxide solution is added and the mixture is stirred for reaction for 5.5h under the condition of cooling to 52°C. After the reaction is completed, the reaction product is cooled to room temperature, washed with distilled water for 4 times, dried with anhydrous magnesium sulfate, and then vacuum filtered. The filtrate is rotary evaporated to remove the solvent to obtain a polyfluoro coupling agent; wherein the CAS number of epichlorohydrin is 106-89-8; the CAS number of tetrabutylammonium bromide is 1643-19-2; Step S6: weighing 35 kg of cement, 75 kg of fly ash, 18 kg of kaolin, 9 kg of water glass, 4 kg of sodium hydroxide, 2 kg of water reducer, 3.7 kg of epoxy long-chain modified whiskers, 2.2 kg of polyfluorine coupling agent and 45 kg of water for standby use; the diameter range of the epoxy long-chain modified whiskers used is 2.6-5.9 μm, and the length range is 62-117 μm; Step S7: adding cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whisker, polyfluorine linking agent and water into a mixer and stirring evenly to obtain a mine filling material based on fly ash solid waste.

[0025] Embodiment 3: This embodiment is a method for preparing a mine filling material based on fly ash solid waste, comprising the following steps: Step S1: 10 mmol of glyceryl monostearate, 25 mmol of maleic anhydride and 50 mL of anhydrous toluene are added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture is stirred at 30° C. and 400 r / min for 20 min, and then 0.08 g of p-toluenesulfonic acid is added and the mixture is heated to 95° C. and stirred for 10 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to distilled water, and then allowed to stand for stratification. The organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a diene fatty acid; wherein the CAS number of glyceryl monostearate is 123-94-4; the CAS number of maleic anhydride is 108-31-6; and the CAS number of p-toluenesulfonic acid is 104-15-4; Step S2: adding 5 g of silicon carbide whiskers and 60 mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer, stirring the reaction for 50 min at a temperature of 30° C. and a stirring rate of 400 r / min, then adding 7 g of diene fatty acid and heating the mixture to 85° C. and continuing to stir the reaction for 4 h. After the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtered, the filter cake is washed with distilled water 5 times, then placed in a vacuum drying oven, and dried at a temperature of 55° C. for 3 h to obtain an olefin long-chain modified whisker; wherein the diameter of the silicon carbide whisker is in the range of 2-5 μm and the length is in the range of 50-100 μm; Step S3: 5 g of olefin long-chain modified whiskers, 10 g of formic acid and 35 mL of 35% hydrogen peroxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred for reaction at a temperature of 15° C. and a stirring rate of 400 r / min for 30 min, and then heated to 55° C. and continued to stir for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water for 5 times, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 5 h to obtain epoxy long-chain modified whiskers; wherein the CAS number of formic acid is 64-18-6; Step S4: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol octafluoropentanol, 0.03 g p-toluenesulfonic acid and 50 mL anhydrous toluene are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 20° C. and a stirring rate of 400 r / min for 15 min, and then the mixture is heated to reflux and stirred for reaction for 4 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a 5% sodium hydroxide solution by mass, and then allowed to stand for stratification. The organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a hydroxy polyfluoro intermediate; wherein the CAS number of 2,2-dihydroxymethylpropionic acid is 4767-03-7; the CAS number of octafluoropentanol is 355-80-6; and the CAS number of p-toluenesulfonic acid is 104-15-4; Step S5: 10mmol of hydroxy polyfluoro intermediate, 120mmol of epichlorohydrin, 0.15g of tetrabutylammonium bromide and 60mL of cyclohexane are added to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30°C and a stirring rate of 400r / min for 15min, and then the mixture is heated to reflux and stirred for reaction for 3h. Then, 30mL of a 45% sodium hydroxide solution is added and the mixture is stirred for reaction for 6h under the condition of cooling to 55°C. After the reaction is completed, the reaction product is cooled to room temperature, washed with distilled water for 5 times, dried with anhydrous magnesium sulfate, and then vacuum filtered. The filtrate is rotary evaporated to remove the solvent to obtain a polyfluoro coupling agent; wherein the CAS number of epichlorohydrin is 106-89-8; the CAS number of tetrabutylammonium bromide is 1643-19-2; Step S6: weighing 40kg of cement, 80kg of fly ash, 21kg of kaolin, 11kg of water glass, 6kg of sodium hydroxide, 3kg of water reducer, 6.1kg of epoxy long-chain modified whiskers, 3.6kg of polyfluorine coupling agent and 50kg of water for standby use; the diameter of the epoxy long-chain modified whiskers is 2.6-5.9μm and the length is 62-117μm; Step S7: adding cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whisker, polyfluorine linking agent and water into a mixer and stirring evenly to obtain a mine filling material based on fly ash solid waste.

[0026] Embodiment 4: This comparative example is different from Example 3 in that the diameter of the epoxy long-chain modified whisker is 8-15 μm and the length is 150-200 μm.

[0027] Embodiment 5:

[0028] The difference between this comparative example and Example 3 is that the diameter of the epoxy long-chain modified whisker is 0.5-1.5 μm and the length is 10-30 μm.

[0029] Comparative Example 1: The difference between this comparative example and Example 3 is that epoxy long-chain modified whiskers and polyfluorinated linking agent are not added, and the remaining steps are the same.

[0030] Comparative Example 2: The difference between this comparative example and Example 3 is that no polyfluoro linking agent is added, and the remaining steps are the same.

[0031] Comparative Example 3: The difference between this comparative example and Example 3 is that no epoxy long-chain modified whiskers are added, and the remaining steps are the same.

[0032] Comparative Example 4: This comparative example is a method for preparing a mine filling material based on fly ash solid waste, comprising the following steps: Step S1: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol octafluoropentanol, 0.03 g p-toluenesulfonic acid and 50 mL anhydrous toluene are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 20° C. and a stirring rate of 400 r / min for 15 min, and then the temperature is raised to reflux and the stirring reaction is continued for 4 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a sodium hydroxide solution with a mass fraction of 5%, and then allowed to stand for stratification. The organic phase is dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a hydroxy polyfluoro intermediate; Step S2: weigh 40kg of cement, 80kg of fly ash, 21kg of kaolin, 11kg of water glass, 6kg of sodium hydroxide, 3kg of water reducer, 6.1kg of silicon carbide whisker, 3.6kg of hydroxyl polyfluoride intermediate and 50kg of water for later use; the cement is P.0 42.5 ordinary Portland cement; the water reducer is polycarboxylate water reducer MT 3800; wherein the diameter of the silicon carbide whisker is 2-5μm and the length is 50-100μm; Step S3: adding cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, silicon carbide whisker, hydroxyl polyfluoride intermediate and water into a mixer and stirring evenly to obtain a mine filling material based on fly ash solid waste.

[0033] That is, the mine filling material of Comparative Example 4 is different from that of Example 3 in that the alkenyl long-chain modified whiskers are replaced by an equal amount of silicon carbide whiskers, and the polyfluorinated linking agent is replaced by an equal amount of hydroxyl polyfluorinated intermediates.

[0034] Wherein, the cement in Examples 1-5 and Comparative Examples 1-4 is P.0 42.5 ordinary Portland cement; The main chemical components of fly ash are as follows:

[0035] The CAS number of kaolin is 1332-58-7; The CAS number of water glass is 1344-09-8; The CAS number of sodium hydroxide is 1310-73-2; The water reducer is polycarboxylate water reducer MT 3800.

[0036] The fly ash solid waste mine filling materials in Examples 1-5 and Comparative Examples 1-4 were prepared into test pieces with a molding size of 40 mm × 40 mm × 160 mm with reference to GB / T17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)", demolded after 24 hours, placed in a standard curing room, and naturally cured in an environment with a temperature of 20°C and a relative humidity of 95%. The test pieces were tested, and the test results are shown in the following table:

[0037] Referring to the data in the above table, based on the comparison between Examples 1-5 and Comparative Examples 1-4, it can be known that the mine filling material based on fly ash solid waste of the present application has excellent mechanical properties and waterproof properties.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0039] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined in this application, they shall all fall within the protection scope of the present invention.

Claims

1. A mine filling material based on fly ash solid waste, characterized in that: It comprises the following components in parts by weight: 30-40 parts of cement, 70-80 parts of fly ash, 15-21 parts of kaolin, 7-11 parts of water glass, 2-6 parts of sodium hydroxide, 1-3 parts of water reducer, 1.3-6.1 parts of epoxy long chain modified whisker, 0.8-3.6 parts of polyfluoride linker and 40-50 parts of water; The epoxy long-chain modified whiskers are obtained by modifying silicon carbide whiskers with diene fatty acids and then epoxidizing them; The polyfluorinated linking agent is obtained by reacting a hydroxy polyfluorinated intermediate with epichlorohydrin.

2. A mine filling material based on fly ash solid waste according to claim 1, characterized in that: The epoxy long-chain modified whisker is prepared by the following steps: Step a1: Stirring glyceryl monostearate, maleic anhydride and anhydrous toluene for reaction, then adding p-toluenesulfonic acid and continuing stirring for reaction, cooling the reaction product after the reaction is completed, then adding it into distilled water, then standing for stratification, drying the organic phase, then vacuum filtering, and rotary evaporating the filtrate to obtain a diene fatty acid; Step a2: Stirring the silicon carbide whiskers and anhydrous ethanol for reaction, then adding the diene fatty acid and continuing the stirring reaction, cooling the reaction product after the reaction is completed, then vacuum filtering, washing and drying the filter cake to obtain the diene long-chain modified whiskers; Step a3: stirring the olefin long-chain modified whiskers, formic acid and hydrogen peroxide to react, cooling the reaction product after the reaction is completed, and then vacuum filtering, washing and drying the filter cake to obtain epoxy long-chain modified whiskers.

3. The mine filling material based on fly ash solid waste according to claim 2, characterized in that: The molar ratio of glyceryl monostearate to maleic anhydride in step a1 is 10:(22-25).

4. The mine filling material based on fly ash solid waste according to claim 2, characterized in that: The mass ratio of the silicon carbide whisker to the diene fatty acid in step a2 is 5:(2-7).

5. The mine filling material based on fly ash solid waste according to claim 2, characterized in that: The mass ratio of the alkenyl long-chain modified whiskers to formic acid in step a3 is 5:(8-10); the mass fraction of the hydrogen peroxide is 30-35%; the diameter of the epoxy long-chain modified whiskers is 2.6-5.9 μm and the length is 62-117 μm.

6. The mine filling material based on fly ash solid waste according to claim 1, characterized in that: The polyfluorinated coupling agent is prepared by the following steps: Step b1: stirring 2,2-dihydroxymethylpropionic acid, octafluoropentanol, p-toluenesulfonic acid and anhydrous toluene to react, cooling the reaction product after the reaction, and then adding it to a sodium hydroxide solution, and then standing to separate the layers, drying the organic phase, and then vacuum filtering, and rotary evaporating the filtrate to obtain a hydroxy polyfluoro intermediate; Step b2: Stir the hydroxypolyfluoro intermediate, epichlorohydrin, tetrabutylammonium bromide and cyclohexane for reaction, then add sodium hydroxide solution and continue stirring the reaction. After the reaction is completed, cool the reaction product, wash and dry it, and then vacuum filter it, and rotary evaporate the filtrate to obtain a polyfluoro linker.

7. The mine filling material based on fly ash solid waste according to claim 6, characterized in that: The molar ratio of the 2,2-dihydroxymethylpropionic acid to octafluoropentanol in step b1 is 1:1; and the mass fraction of the sodium hydroxide solution is 3-5%.

8. The mine filling material based on fly ash solid waste according to claim 6, characterized in that: The molar ratio of the hydroxy polyfluoro intermediate to epichlorohydrin in step b2 is 10:100-120; the mass fraction of the sodium hydroxide solution is 40-45%.

9. A method for preparing mine filling materials based on fly ash solid waste, characterized in that: The following steps are involved: Step 1: Weigh 30-40 parts of cement, 70-80 parts of fly ash, 15-21 parts of kaolin, 7-11 parts of water glass, 2-6 parts of sodium hydroxide, 1-3 parts of water reducer, 1.3-6.1 parts of epoxy long-chain modified whisker, 0.8-3.6 parts of polyfluoride linker and 40-50 parts of water according to weight parts, and set aside; Step 2: Add cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whisker, polyfluorine linking agent and water into a mixer and mix them evenly to obtain a mine filling material based on fly ash solid waste.

10. The method for preparing a mine filling material based on fly ash solid waste according to claim 9, characterized in that: The cement is P.0 42.5 ordinary Portland cement; the water reducer is polycarboxylate water reducer MT 3800.

Images