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

Abstract

The present application relates to the field of filling material, in particular to a kind of mine filling material based on fly ash solid waste and its preparation method, for solving the problems that the strength and durability of existing filling material are not good, it is difficult to meet the special requirements of mine goaf filling;The preparation method makes full use of fly ash, an industrial solid waste, as the main raw material, reduces the impact of large amounts of fly ash stockpiling on the environment and the damage of toxic heavy metals in fly ash to the soil, saves land resources, while significantly reducing the cost of mine filling material, realizes large-scale resource utilization of waste, has significant environmental and economic benefits, by adding epoxy long-chain modified whisker and polyfluoro coupling agent, the mechanical properties and waterproof performance of the mine filling material can be greatly improved, which can effectively fill the mine goaf, ensure the safe production of mine, meet the requirements of mine filling, and provide strong support for the sustainable development of mining industry.

Description

TECHNICAL FIELD

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

[0002] With the continuous warming of global mining activities, the task of goaf backfilling is becoming more and more difficult. The existing mine filling materials are mainly natural materials such as soil, stone and sand, which have single properties and are difficult to meet the special requirements of different mine filling. In addition, the resources of natural materials are limited, and the cost of mining and transportation is high. Therefore, it is of great significance to explore low-cost and environmentally friendly mine filling materials. Fly ash is a large amount of solid waste generated in the power generation industry, with an annual emission of hundreds of millions of tons. For a long time, it has occupied vast land and caused serious threats to soil and water ecology due to the heavy metals and harmful substances it contains. Although there have been some explorations of using fly ash to prepare mine filling materials, the existing fly ash mine filling material products still have significant shortcomings in mechanical property strengthening and erosion resistance improvement, resulting in poor strength and durability of the filling material, which is difficult to meet the special requirements of mine goaf filling. SUMMARY

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

[0004] The purpose of the present application can be achieved by the following technical solutions:

[0005] A mine filling material based on fly ash solid waste, comprising the following components by weight:

[0006] cement 30-40 parts, fly ash 70-80 parts, kaolin 15-21 parts, water glass 7-11 parts, sodium hydroxide 2-6 parts, water reducing agent 1-3 parts, epoxy long-chain modified whisker 1.3-6.1 parts, multi-fluorine coupling agent 0.8-3.6 parts and water 40-50 parts;

[0007] The epoxy long-chain modified whisker is obtained by modifying silicon carbide whisker with double-alkenyl fatty acid and then epoxidizing;

[0008] The multi-fluorine coupling agent is obtained by reacting hydroxyl multi-fluorine intermediate and epichlorohydrin.

[0009] The epoxy long-chain modified whisker is prepared by the following steps:

[0010] Step a1: glyceryl monostearate, maleic anhydride and anhydrous toluene are added to a three-necked flask equipped with a stirrer, a thermometer, stirred at a temperature of 25-30℃ and a stirring rate of 300-400 r / min for 15-20 min, then p-toluenesulfonic acid is added and the temperature is raised to 90-95℃ and the stirring is continued for 9-10 h, the reaction is completed, the reaction product is cooled to room temperature, then added to distilled water, then placed to separate layers, the organic phase is dried with anhydrous magnesium sulfate, then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and a diene-based fatty acid is obtained;

[0011] Step a2: silicon carbide whiskers and anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer, stirred at a temperature of 25-30℃ and a stirring rate of 300-400 r / min for 30-50 min, then the diene-based fatty acid is added and the temperature is raised to 80-85℃ and the stirring is continued for 3-4 h, the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtered, the filter cake is washed with distilled water for 3-5 times, then placed in a vacuum drying oven and dried at a temperature of 50-55℃ for 2-3 h, and an alkenyl long-chain modified whisker is obtained.

[0012] Step a3: the alkenyl long-chain modified whisker, formic acid and hydrogen peroxide are added to a three-necked flask equipped with a stirrer, a thermometer, stirred at a temperature of 10-15℃ and a stirring rate of 300-400 r / min for 20-30 min, then the temperature is raised to 50-55℃ and the stirring is continued for 3-4 h, the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtered, the filter cake is washed with distilled water for 3-5 times, then placed in a vacuum drying oven and dried at a temperature of 50-55℃ for 4-5 h, and an epoxy long-chain modified whisker is obtained.

[0013] As a further scheme of the present application: the amount 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.

[0014] As a further scheme of the present application: the amount ratio of the silicon carbide whisker, anhydrous ethanol and diene-based fatty acid in step a2 is 5 g: 50-60 mL: 2-7 g.

[0015] As a further scheme of the present application: 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.

[0016] As a further scheme of the present application: the amount ratio of the alkenyl long-chain modified whisker, formic acid and hydrogen peroxide in step a3 is 5 g: 8-10 g: 30-35 mL.

[0017] As a further scheme of the present application: the mass fraction of the hydrogen peroxide in step a3 is 30-35%.

[0018] As a further scheme of the present application: the diameter of the epoxy long-chain modified whisker in step a3 is 2.6-5.9μm, and the length is 62-117μm.

[0019] As a further scheme of the present application: the polyfluorinated coupling agent is prepared by the following steps:

[0020] Step b1: 2,2-dimethylol propionic acid, octafluoropentanol, p-toluenesulfonic acid and anhydrous toluene are added into a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser, and protected by nitrogen, stirred at a temperature of 15-20℃ and a stirring rate of 300-400r / min for 10-15min, then heated to reflux and stirred for 3-4h, after the reaction, the reaction product is cooled to room temperature, then added into a sodium hydroxide solution, and then separated by layering, the organic phase is dried with anhydrous magnesium sulfate, then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and a hydroxyl polyfluorinated intermediate is obtained;

[0021] Step b2: the hydroxyl polyfluorinated intermediate, epichlorohydrin, tetrabutylammonium bromide and cyclohexane are added into a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser, and protected by nitrogen, stirred at a temperature of 25-30℃ and a stirring rate of 300-400r / min for 10-15min, then heated to reflux and stirred for 2-3h, then added with a sodium hydroxide solution and cooled to 50-55℃ and stirred for 5-6h, after the reaction, the reaction product is cooled to room temperature, then washed with distilled water for 3-5 times, then dried with anhydrous magnesium sulfate, then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and a polyfluorinated coupling agent is obtained.

[0022] As a further scheme of the present application: the amount of the 2,2-dimethylol propionic acid, octafluoropentanol, p-toluenesulfonic acid and anhydrous toluene in step b1 is 10mmol: 10mmol: 0.01-0.03g: 40-50mL.

[0023] As a further scheme of the present application: the mass fraction of the sodium hydroxide solution in step b1 is 3-5%.

[0024] As a further scheme of the present application: the amount ratio of the hydroxyl polyfluorinated intermediate, epichlorohydrin, tetrabutylammonium bromide, cyclohexane and sodium hydroxide solution in step b2 is 10mmol: 100-120mmol: 0.05-0.15g: 50-60mL: 25-30mL.

[0025] As a further scheme of the present application: the mass fraction of the sodium hydroxide solution in step b2 is 40-45%.

[0026] As a further scheme of the present application: a preparation method of a mine filling material based on fly ash solid waste, comprising the following steps:

[0027] Step one: according to weight parts, cement 30-40 parts, fly ash 70-80 parts, kaolin 15-21 parts, water glass 7-11 parts, sodium hydroxide 2-6 parts, water reducing agent 1-3 parts, epoxy long chain modified whisker 1.3-6.1 parts, polyfluorinated coupling agent 0.8-3.6 parts and water 40-50 parts are weighed and prepared;

[0028] Step two: the cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long chain modified whisker, polyfluorinated coupling agent and water are added into a blender and stirred uniformly to obtain a mine filling material based on fly ash solid waste.

[0029] As a further scheme of the present application: the cement is P.0 42.5 ordinary portland cement; the water reducing agent is polycarboxylic acid water reducing agent MT 3800.

[0030] The present application has the following advantages:

[0031] The present application discloses a mine filling material based on fly ash solid waste and a preparation method thereof, which comprises the following steps: adding cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long chain modified whisker, polyfluorinated coupling agent and water into a blender and stirring uniformly to obtain a mine filling material based on fly ash solid waste.

[0032] The process for preparing the mine filling material based on fly ash solid waste adds epoxy long-chain modified whiskers. First, glycerol monostearate and maleic anhydride are reacted, the hydroxyl groups on the glycerol monostearate react with the anhydride groups on the maleic anhydride, and olefin groups and carboxyl groups are introduced at the same time to obtain a double-olefin fatty acid. Then, the double-olefin fatty acid is used to modify the silicon carbide whisker. The double-olefin fatty acid reacts with the hydroxyl groups on the silicon carbide whisker through the carboxyl groups to graft an olefin long carbon chain to the silicon carbide whisker to obtain an olefin long-chain modified whisker. Then, the Prilezhaev method is used to epoxidize the olefin groups on the olefin long-chain modified whisker into epoxy groups to obtain an epoxy long-chain modified whisker. The silicon carbide whisker has the characteristics of high strength, high modulus and excellent heat resistance, can greatly enhance the mechanical properties of the mine filling material, and when the filling material is subjected to external force, the silicon carbide whisker can form a bridge between the cracks to hinder the further development of the cracks, thereby improving the toughness of the material. After the modification of the silicon carbide whisker, the surface properties of the silicon carbide whisker are improved, so that the silicon carbide whisker is uniformly dispersed in the filling material system to avoid agglomeration, so that it can better combine with the matrix material and fully exert its high strength and high modulus characteristics to provide excellent mechanical enhancement effect for the material. And the introduced epoxy groups can chemically bond with other components to improve the interfacial adhesion strength, strengthen the interfacial bonding force, and improve the overall strength of the filling material.

[0033] The process for preparing the mine filling material based on fly ash solid waste also adds a polyfluoro coupling agent. First, 2,2-dihydroxymethyl propionic acid and octafluoropentanol are reacted. The carboxyl groups on the 2,2-dihydroxymethyl propionic acid react with the hydroxyl groups on the octafluoropentanol to form an esterification reaction to obtain a hydroxyl polyfluoro intermediate. Then, the hydroxyl polyfluoro intermediate and epichlorohydrin are reacted. The epichlorohydrin can introduce an epoxy group to the hydroxyl polyfluoro intermediate after ring opening-closing to obtain a polyfluoro coupling agent. The polyfluoro coupling agent can crosslink with the surface active sites of each component of the fly ash of the mine filling material through the epoxy groups on its molecular structure to form a three-dimensional network structure. When the material is stressed, it can work together to improve the overall strength and stability of the material, and play an excellent buffering and toughening role. Moreover, a large number of fluorine atoms can form a dense fluoride protective layer on the surface of the material due to their super-strong electronegativity, effectively blocking water, acid, alkali and other erosion media in the mine environment, making it difficult for corrosive media to infiltrate and penetrate into the interior of the filling material, significantly enhancing the chemical stability and durability of the filling material, effectively protecting the matrix structure of the filling material, and prolonging the service life of the filling material. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0035] Embodiment 1

[0036] The embodiment is a preparation method of a mine filling material based on fly ash solid waste, comprising the following steps:

[0037] Step S1: 10 mmol of glycerol monostearate, 22 mmol of maleic anhydride and 40 mL of anhydrous toluene are added to a three-necked flask provided with a stirrer and a thermometer, and stirred at a temperature of 25℃ and a stirring rate of 300 r / min for 15 min, then 0.04 g of p-toluenesulfonic acid is added and the reaction is continued to be stirred at a temperature of 90℃ for 9 h, after the reaction is completed, the reaction product is cooled to room temperature, then added to distilled water, and then left to separate into layers, the organic phase is dried with anhydrous magnesium sulfate, then vacuum filtration is performed, the filtrate is rotary evaporated to remove the solvent, and a double-alkenyl fatty acid is obtained; wherein the CAS number of the glycerol monostearate is 123-94-4; the CAS number of the maleic anhydride is 108-31-6; and the CAS number of the p-toluenesulfonic acid is 104-15-4;

[0038] Step S2: 5 g of silicon carbide whiskers and 50 mL of anhydrous ethanol are added to a three-necked flask provided with a stirrer and a thermometer, and stirred at a temperature of 25℃ and a stirring rate of 300 r / min for 30 min, then 2 g of the double-alkenyl fatty acid is added and the reaction is continued to be stirred at a temperature of 80℃ for 3 h, after the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtration is performed, 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℃ for 2 h, and an alkenyl long-chain modified whisker is obtained; wherein the diameter of the silicon carbide whisker is 2-5 μm, and the length is 50-100 μm;

[0039] Step S3: 5 g of the alkenyl long-chain modified whisker, 8 g of formic acid and 30 mL of 30% hydrogen peroxide are added to a three-necked flask provided with a stirrer and a thermometer, and stirred at a temperature of 10℃ and a stirring rate of 300 r / min for 20 min, then the temperature is increased to 50℃ and the reaction is continued to be stirred for 3 h, after the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtration is performed, 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℃ for 4 h, and an epoxy long-chain modified whisker is obtained; wherein the CAS number of the formic acid is 64-18-6;

[0040] Step S4: 10 mmol 2,2-dimethylolpropionic acid, 10 mmol octafluoropentanol, 0.01 g p-toluenesulfonic acid and 40 mL anhydrous toluene were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 15° C. and a stirring rate of 300 r / min for 10 minutes, and then the temperature was raised to reflux and the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to a 3% sodium hydroxide solution. The mixture was allowed to stand for stratification, and the organic phase was dried over anhydrous magnesium sulfate. The organic phase was then vacuum filtered and the filtrate was rotary evaporated to remove the solvent to obtain a hydroxy polyfluoro intermediate; wherein the CAS number of 2,2-dimethylolpropionic 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;

[0041] Step S5: 10 mmol of the hydroxy polyfluoro intermediate, 100 mmol of epichlorohydrin, 0.05 g of tetrabutylammonium bromide, and 50 mL of cyclohexane were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, and a reflux condenser. Nitrogen protection was introduced, and the mixture was stirred at 25° C. and a stirring rate of 300 r / min for 10 minutes. The mixture was then heated to reflux and stirred for 2 hours. 25 mL of a 40% sodium hydroxide solution was then added and the mixture was cooled to 50° C. and stirred for 5 hours. After the reaction, the reaction product was cooled to room temperature, washed with distilled water three times, dried over anhydrous magnesium sulfate, and vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a polyfluoro coupling agent. The CAS number of epichlorohydrin is 106-89-8; the CAS number of tetrabutylammonium bromide is 1643-19-2.

[0042] Step S6: Weigh 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 polyfluorinated coupling agent, and 40 kg of water, and set aside; the epoxy long-chain modified whiskers used have a diameter range of 2.6-5.9 μm and a length range of 62-117 μm;

[0043] Step S7: adding cement, fly ash, kaolin, water glass, sodium hydroxide, water reducer, epoxy long-chain modified whisker, polyfluorinated linker and water into a mixer and stirring evenly to obtain a mine filling material based on fly ash solid waste.

[0044] Example 2:

[0045] This embodiment is a method for preparing a mine filling material based on fly ash solid waste, comprising the following steps:

[0046] Step S1: 10 mmol of glycerol monostearate, 24 mmol of maleic anhydride, and 45 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, a thermometer, and stirred at a temperature of 28℃ and a stirring rate of 350 r / min for 18 min, then 0.06 g of p-toluenesulfonic acid was added and the reaction was continued to be stirred at a temperature of 92℃ for 9.5 h, after the reaction was completed, the reaction product was cooled to room temperature, then added to distilled water, then separated by standing, the organic phase was dried with anhydrous magnesium sulfate, then vacuum filtration, the filtrate was rotary evaporated to remove the solvent, to obtain a diene-based fatty acid; wherein the CAS number of glycerol monostearate is 123-94-4; the CAS number of maleic anhydride is 108-31-6; the CAS number of p-toluenesulfonic acid is 104-15-4;

[0047] Step S2: 5 g of silicon carbide whiskers and 55 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 28℃ and a stirring rate of 350 r / min for 40 min, then 4.5 g of diene-based fatty acid was added and the reaction was continued to be stirred at a temperature of 82℃ for 3.5 h, after the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtration, the filter cake was washed with distilled water for 4 times, then placed in a vacuum drying oven and dried at a temperature of 52℃ for 2.5 h, to obtain an alkenyl long-chain modified whisker; wherein the diameter of the silicon carbide whisker is 2-5 μm and the length is 50-100 μm;

[0048] Step S3: 5 g of alkenyl long-chain modified whisker, 9 g of formic acid, and 32 mL of 32% mass fraction of hydrogen peroxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 12℃ and a stirring rate of 350 r / min for 25 min, then the temperature was raised to 52℃ and the reaction was continued to be stirred for 3.5 h, after the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtration, the filter cake was washed with distilled water for 4 times, then placed in a vacuum drying oven and dried at a temperature of 52℃ for 4.5 h, to obtain an epoxy long-chain modified whisker; wherein the CAS number of formic acid is 64-18-6;

[0049] Step S4: 10 mmol of 2,2-dimethylol propionic acid, 10 mmol of octafluoropentanol, 0.02 g of p-toluenesulfonic acid and 45 mL of anhydrous toluene were added into a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser, and protected by nitrogen, and stirred at a temperature of 18℃ and a stirring rate of 350 r / min for 12 min, and then stirred at a reflux temperature for 3.5 h, and then the reaction product was cooled to room temperature, and then added into a 4% sodium hydroxide solution, and then separated by standing, and the organic phase was dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent, to obtain a hydroxyl polyfluoro intermediate; the CAS number of 2,2-dimethylol propionic acid is 4767-03-7; the CAS number of octafluoropentanol is 355-80-6; the CAS number of p-toluenesulfonic acid is 104-15-4;

[0050] Step S5: 10 mmol of the hydroxyl polyfluoro intermediate, 110 mmol of epichlorohydrin, 0.1 g of tetrabutylammonium bromide and 55 mL of cyclohexane were added into a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser, and protected by nitrogen, and stirred at a temperature of 28℃ and a stirring rate of 350 r / min for 12 min, and then stirred at a reflux temperature for 2.5 h, and then 28 mL of a 42% sodium hydroxide solution was added and stirred at a temperature of 52℃ for 5.5 h, and then the reaction product was cooled to room temperature, and then washed with distilled water for 4 times, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent, to obtain a polyfluoro coupling agent; the CAS number of epichlorohydrin is 106-89-8; the CAS number of tetrabutylammonium bromide is 1643-19-2;

[0051] Step S6: 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 reducing agent, 3.7 kg of epoxy long-chain modified whiskers, 2.2 kg of polyfluoro coupling agent and 45 kg of water were weighed and prepared; the diameter of the epoxy long-chain modified whiskers was 2.6-5.9 μm, and the length was 62-117 μm;

[0052] Step S7: the cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whiskers, polyfluoro coupling agent and water were added into a mixer and stirred uniformly, to obtain a fly ash solid waste-based mine filling material.

[0053] Example 3:

[0054] The embodiment is a preparation method of a fly ash solid waste-based mine filling material, which comprises the following steps:

[0055] Step S1: 10 mmol of glycerol monostearate, 25 mmol of maleic anhydride, and 50 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 30°C and a stirring rate of 400 r / min for 20 min, then 0.08 g of p-toluenesulfonic acid was added and the reaction was continued at a temperature of 95°C for 10 h. After the reaction was completed, the reaction product was cooled to room temperature, then added to distilled water, and then separated by standing. The organic phase was dried with anhydrous magnesium sulfate, then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent to obtain a diene-based fatty acid. The CAS number of glycerol 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;

[0056] Step S2: 5 g of silicon carbide whiskers and 60 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 30°C and a stirring rate of 400 r / min for 50 min, then 7 g of diene-based fatty acid was added and the reaction was continued at a temperature of 85°C for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, and the filter cake was washed with distilled water for 5 times, then placed in a vacuum drying oven and dried at a temperature of 55°C for 3 h to obtain an alkenyl long-chain modified whisker. The diameter of the silicon carbide whisker ranges from 2 to 5 μm, and the length ranges from 50 to 100 μm;

[0057] Step S3: 5 g of alkenyl long-chain modified whisker, 10 g of formic acid, and 35 mL of 35% mass fraction of hydrogen peroxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 15°C and a stirring rate of 400 r / min for 30 min, then heated to a temperature of 55°C and continued to stir for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, and the filter cake was washed with distilled water for 5 times, then placed in a vacuum drying oven and dried at a temperature of 55°C for 5 h to obtain an epoxy long-chain modified whisker. The CAS number of formic acid is 64-18-6;

[0058] Step S4: 10 mmol of 2,2-dimethylol propionic acid, 10 mmol of octafluoropentanol, 0.03 g of p-toluenesulfonic acid and 50 mL of anhydrous toluene were added into a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser, and protected by nitrogen, and stirred at a temperature of 20 DEG C and a stirring speed of 400 r / min for 15 min, and then stirred at reflux for 4 h, and then the reaction product was cooled to room temperature, and then added into a 5% sodium hydroxide solution, and then separated by standing, and the organic phase was dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent, to obtain a hydroxyl polyfluoro intermediate; the CAS number of 2,2-dimethylol propionic acid is 4767-03-7; the CAS number of octafluoropentanol is 355-80-6; the CAS number of p-toluenesulfonic acid is 104-15-4;

[0059] Step S5: 10 mmol of the hydroxyl polyfluoro intermediate, 120 mmol of epichlorohydrin, 0.15 g of tetrabutylammonium bromide and 60 mL of cyclohexane were added into a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser, and protected by nitrogen, and stirred at a temperature of 30 DEG C and a stirring speed of 400 r / min for 15 min, and then stirred at reflux for 3 h, and then 30 mL of a 45% sodium hydroxide solution was added and stirred at a temperature of 55 DEG C for 6 h, and then the reaction product was cooled to room temperature, and then washed with distilled water for 5 times, and then dried over anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent, to obtain a polyfluoro coupling agent; the CAS number of epichlorohydrin is 106-89-8; the CAS number of tetrabutylammonium bromide is 1643-19-2;

[0060] Step S6: cement 40 kg, fly ash 80 kg, kaolin 21 kg, water glass 11 kg, sodium hydroxide 6 kg, water reducing agent 3 kg, epoxy long-chain modified whisker 6.1 kg, polyfluoro coupling agent 3.6 kg and water 50 kg were weighed and prepared; the diameter of the epoxy long-chain modified whisker was 2.6-5.9 μm, and the length was 62-117 μm;

[0061] Step S7: the cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, epoxy long-chain modified whisker, polyfluoro coupling agent and water were added into a mixer and stirred uniformly, to obtain a mine filling material based on fly ash solid waste.

[0062] Example 4:

[0063] The 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.

[0064] Example 5:

[0065] The present comparative example differs from Example 3 in that the diameter of the epoxy long-chain modified whisker is 0.5-1.5 μm and the length is 10-30 μm.

[0066] Comparative Example 1:

[0067] The present comparative example differs from Example 3 in that no epoxy long-chain modified whisker and polyfluoro coupling agent are added, and the remaining steps are the same.

[0068] Comparative Example 2:

[0069] The present comparative example differs from Example 3 in that no polyfluoro coupling agent is added, and the remaining steps are the same.

[0070] Comparative Example 3:

[0071] The present comparative example differs from Example 3 in that no epoxy long-chain modified whisker is added, and the remaining steps are the same.

[0072] Comparative Example 4:

[0073] The present comparative example is a preparation method of a mine filling material based on fly ash solid waste, comprising the following steps:

[0074] Step S1: 10 mmol of 2,2-dimethylol propionic acid, 10 mmol of octafluoropentanol, 0.03 g of p-toluenesulfonic acid, and 50 mL of anhydrous toluene are added to a three-necked flask equipped with a stirrer, a thermometer, a gas inlet tube, and a reflux condenser, nitrogen is introduced for protection, stirring is carried out at a temperature of 20°C and a stirring rate of 400 r / min for 15 min, then the temperature is raised to reflux and the stirring is continued for 4 h, after the reaction is completed, the reaction product is cooled to room temperature, then added to a 5% sodium hydroxide solution, then left to separate into layers, the organic phase is dried with anhydrous magnesium sulfate, then vacuum filtration is carried out, the filtrate is rotary evaporated to remove the solvent, and a hydroxyl polyfluoro intermediate is obtained;

[0075] Step S2: 40 kg of cement, 80 kg of fly ash, 21 kg of kaolin, 11 kg of water glass, 6 kg of sodium hydroxide, 3 kg of water reducing agent, 6.1 kg of silicon carbide whisker, 3.6 kg of hydroxyl polyfluoro intermediate, and 50 kg of water are weighed and prepared; the cement is P.0 42.5 ordinary portland cement; the water reducing agent is polycarboxylic acid water reducing agent MT 3800; wherein the diameter of the silicon carbide whisker is 2-5 μm and the length is 50-100 μm;

[0076] Step S3: cement, fly ash, kaolin, water glass, sodium hydroxide, water reducing agent, silicon carbide whisker, hydroxyl polyfluoro intermediate and water were added into a blender and stirred uniformly to obtain a mine filling material based on fly ash solid waste.

[0077] That is, the mine filling material of Comparative Example 4 is different from that of Example 3 in that the alkenyl long-chain modified whisker is replaced with an equal amount of silicon carbide whisker, and the polyfluoro coupling agent is replaced with an equal amount of hydroxyl polyfluoro intermediate.

[0078] In the examples 1-5 and comparative examples 1-4, the cement is P.0 42.5 ordinary portland cement.

[0079] The main chemical components of fly ash are as follows:

[0080]

[0081] The CAS number of kaolin is 1332-58-7.

[0082] The CAS number of water glass is 1344-09-8.

[0083] The CAS number of sodium hydroxide is 1310-73-2.

[0084] The water reducing agent is polycarboxylic acid water reducing agent MT 3800.

[0085] The mine filling material based on fly ash solid waste in examples 1-5 and comparative examples 1-4 was prepared into a test piece with a molding size of 40mm×40mm×160mm according to GB / T 17671-2021 “Cement mortar strength test method (ISO method)”, demolded after 24h, and placed in a standard curing room for natural curing in an environment with a temperature of 20℃ and a relative humidity of 95%, and the test piece was tested, and the test results are shown in the following table:

[0086]

[0087] Referring to the data in the above table, according to 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 performance.

[0088] In the description of the present specification, the description of the terms “one embodiment”, “example”, “specific example” and the like 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 application. In the present specification, the illustrative description 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.

[0089] The above merely provides the illustration and description of the present application. Those skilled in the art can make various modifications or supplement to the described specific embodiments or adopt similar ways to replace, as long as it does not deviate from the present application or beyond the scope defined in the present application.

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 whiskers, 0.8-3.6 parts of polyfluorinated coupling agent 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 epoxy long-chain modified whiskers are prepared by the following steps: Step a1: stirring glyceryl monostearate, maleic anhydride, and anhydrous toluene to react, then adding p-toluenesulfonic acid and continuing stirring the reaction. After the reaction is completed, the reaction product is cooled and then added to distilled water. The mixture is allowed to stand for stratification, and the organic phase is dried. The mixture is then vacuum filtered and the filtrate is rotary evaporated to obtain a diene fatty acid. Step a2: Stirring silicon carbide whiskers and anhydrous ethanol for reaction, then adding diene fatty acid and continuing to stir and react. After the reaction is completed, the reaction product is cooled, then vacuum filtered, and the filter cake is washed and dried to obtain diene long-chain modified whiskers; Step a3: stirring the alkenyl long-chain modified whiskers, formic acid, and hydrogen peroxide to react. After the reaction is completed, the reaction product is cooled, and then vacuum filtered. The filter cake is washed and dried to obtain epoxy long-chain modified whiskers; The polyfluoro linker is obtained by reacting a hydroxy polyfluoro intermediate with epichlorohydrin, and the polyfluoro linker is prepared by the following steps: Step b1: stirring 2,2-dihydroxymethylpropionic acid, octafluoropentanol, p-toluenesulfonic acid and anhydrous toluene to react. After the reaction, the reaction product is cooled and then added to a sodium hydroxide solution. The mixture is allowed to stand for stratification, and the organic phase is dried. The organic phase is then vacuum filtered and the filtrate is rotary evaporated to obtain a hydroxy polyfluoro intermediate. Step b2: Stirring the hydroxy polyfluoro intermediate, epichlorohydrin, tetrabutylammonium bromide and cyclohexane, then adding sodium hydroxide solution and continuing to stir the reaction. After the reaction is completed, the reaction product is cooled, washed, dried, and then vacuum filtered. The filtrate is rotary evaporated to obtain a polyfluoro linker.

2. The mine filling material based on fly ash solid waste according to claim 1, characterized in that: The molar ratio of the glyceryl monostearate to maleic anhydride in step a1 is 10:(22-25).

3. The mine filling material based on fly ash solid waste according to claim 1, characterized in that: The mass ratio of the silicon carbide whiskers to the diene fatty acid in step a2 is 5:(2-7).

4. The mine filling material based on fly ash solid waste according to claim 1, 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.

5. The mine filling material based on fly ash solid waste according to claim 1, 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%.

6. The mine filling material based on fly ash solid waste according to claim 1, 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%.

7. A method for preparing a mine filling material based on fly ash solid waste according to any one of claims 1 to 6, 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 whiskers, 0.8-3.6 parts of polyfluorinated coupling agent 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 reducer, epoxy long-chain modified whisker, polyfluorinated linker and water into a mixer and mix them evenly to obtain a mine filling material based on fly ash solid waste.

8. The method for preparing a mine filling material based on fly ash solid waste according to claim 7, characterized in that: The cement is P.0 42.5 ordinary Portland cement; the water reducer is polycarboxylate water reducer MT 3800.

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