Mine filling curing material prepared from household garbage incineration fly ash and preparation method of mine filling curing material

Abstract

The invention discloses a mine filling curing material prepared from household garbage incineration fly ash and a preparation method, and relates to the technical field of waste recycling, the mine filling curing material comprises the following raw materials by mass: 25-35 parts of a filling curing agent, 18-24 parts of coarse tailings, 12-16 parts of fine tailings, 7-9 parts of deionized water, and 0.3-0.6 part of a fly ash modifier. On the basis of harmless treatment of the fly ash, the fly ash modifier is added to improve the performance and strength of the filling slurry, so that the fly ash can be effectively applied to mine filling, the problems of fly ash landfill and secondary pollution are reduced, and under the complexing and solubilizing effects, the fly ash can be recycled, and the service life of the filling slurry is prolonged. The fly ash modifier forms more hydrated calcium silicate in the hydration process of the filler curing agent, the hydration reaction of mineral powder and harmless fly ash is promoted, and the compressive strength of the filler is improved through the cooperation of the volcanic ash activity excitation effect of the nano silica fume and the micro-aggregate filling effect of the floating beads.

Description

Technical Field

[0001] The present invention relates to the technical field of waste recycling and reuse. Specifically, it relates to a mine filling solidification material prepared from municipal solid waste incineration fly ash and a preparation method thereof. Background Art

[0002] Fly ash is the material collected after garbage incineration through heat recovery and flue gas purification systems. The amount of fly ash generated from garbage incineration is related to the type of garbage, incineration equipment, and treatment process. Usually, it is 3%-5% of the total amount of incinerated garbage. Its main substances and heavy metal contents are relatively high. These heavy metals and organic compounds have very high leaching toxicity, increasing the difficulty of disposing of the pollutants generated by fly ash. If it is discharged into the environment without treatment, it is likely to cause secondary pollution to the atmosphere, water bodies, etc. The common treatment method for existing fly ash is mainly landfill treatment. This treatment method is likely to occupy a large amount of land resources and requires a large increase in infrastructure costs. Long-term landfill treatment will cause groundwater pollution. At the same time, due to the increase in fly ash production, the sites available for landfill are becoming fewer and fewer. Existing fly ash treatment technologies have problems of low practicability and functionality.

[0003] Regarding the problems in the related technology, no effective solution has been proposed yet. Summary of the Invention

[0004] Regarding the problems in the related technology, the present invention proposes a mine filling solidification material prepared from municipal solid waste incineration fly ash and a preparation method thereof to overcome the above technical problems.

[0005] Therefore, the specific technical solutions adopted by the present invention are as follows: The mine filling solidification material prepared from municipal solid waste incineration fly ash includes the following raw materials in parts by mass: 25-35 parts of filling solidifying agent, 18-24 parts of coarse tailings, 12-16 parts of fine tailings, 7-9 parts of deionized water, 0.3-0.6 part of fly ash modifier. The filling solidifying agent is composed of harmless fly ash, S95 slag powder, building gypsum powder, and quicklime. Among them, the fly ash modifier is prepared by the following steps: Step 1: Add deionized water to a stirring reaction kettle, and then sequentially add N-methylolacrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, and ferrous sulfate solution and stir at room temperature for 30 minutes to obtain premix A. Step 2: Heat premix A to 60°C and uniformly dropwise add a mixed preparation. The raw materials of the mixed preparation are acrylic acid and hydroxybutyl acrylate. When adding the mixed preparation for 30 minutes, add stannous chloride and continue to complete the addition of the remaining mixed preparation to obtain premix B. Step 3: After the preparation of premix B is completed, maintain the reaction at 60°C for 30 minutes, then add pentanediol, and continue the reaction for 60 minutes. Subsequently, transfer it to a spray dryer, set the inlet temperature at 180°C and the outlet temperature at 80°C, and dry to obtain a concrete stabilizer. Add the concrete stabilizer, complexing agent, defoaming agent, and penetrant into a high-speed mixer and mix to obtain an activator; Step 4: Add nano-silica fume, cenospheres, and activator into a three-dimensional mixer and mix to obtain a fly ash modifier, which can enhance the strength and impermeability performance and effectively solidify heavy metals.

[0006] As a preferred embodiment, the mass ratio of acrylic acid to hydroxybutyl acrylate used in Step 2 is 13:27, the total duration of the uniform dropping of the mixed preparation is 60 minutes, the temperature is set at 60±2°C, and the stirring speed is 400 rpm.

[0007] As a preferred embodiment, the mass ratio of deionized water, N-methylol acrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, and pentanediol used in Steps 1, 2, and 3 is 300:10:200:25:5:5:13:27:2:35.

[0008] As a preferred embodiment, the concentration of ferrous sulfate used in Step 1 is 0.1%, and the normal temperature stirring speed is 300 rpm.

[0009] As a preferred embodiment, the mass ratio of nano-silica fume, cenospheres, and activator used in Step 4 is 1:1:2, the mixing time is 30 minutes, the rotation speed is set at 500 rpm, the silica content of nano-silica fume > 90%, the specific surface area of nano-silica fume > 200m 2 / g, the silica content of cenospheres > 60%, the alumina content > 30%, and the density of cenospheres < 0.7cm 2 / g.

[0010] As a preferred embodiment, the mass ratio of the concrete stabilizer, complexing agent, defoaming agent, and penetrant in Step 3 is 5.5:1.5:1.5:2, where the complexing agent is one or two of diethylenetriamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is one or two of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylene amine ether, or polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is one or two of isooctyltriethoxysilane, secondary alkyl sulfate ester sodium, or α-olefin sulfonate sodium.

[0011] A preparation method of a mine filling and solidifying material, characterized by including the following preparation steps: S1. Screen the collected municipal solid waste incineration fly ash through a vibrating screen, place the fly ash after screening in a desorption device, heat it to 350 - 400 °C for 60 minutes to remove dioxins and obtain harmless fly ash; S2. Premix building gypsum powder and quicklime for 5 minutes, then add the harmless fly ash and S95 mineral powder and continue to mix for 20 minutes to obtain a filling curing agent; S3. Weigh the following raw materials by mass parts: 25 - 35 parts of filling curing agent, 18 - 24 parts of coarse tailings, 12 - 16 parts of fine tailings, 7 - 9 parts of deionized water, 0.3 - 0.6 parts of fly ash modifier; S4. Add the coarse tailings, fine tailings, filling curing agent, and fly ash modifier into a forced mixer in sequence, dry - mix for 3 minutes, and then slowly add deionized water and continuously stir to obtain a mine filling curing material.

[0012] As a preferred embodiment, in S2, the mass ratio of the harmless fly ash, S95 mineral powder, building gypsum powder, and quicklime is 9:9:1:1, and the stirring speed is 35 rpm.

[0013] As a preferred embodiment, in S1, the screen holes of the vibrating screen are 2 - 5 mm, and in S4, the continuous stirring time is 8 - 10 minutes, and the stirring speed is 200 rpm.

[0014] The beneficial effects of the present invention are as follows: 1. By adding a fly ash modifier to the filler curing agent prepared from harmless fly ash, under the complexing and solubilization action, more hydrated calcium silicate is formed during the hydration process of the filler curing agent by the fly ash modifier, which promotes the hydration reaction of the mineral powder and the harmless fly ash, and solidifies the difficult - to - treat chloride ions in the fly ash. By providing active silicon ions and aluminum ions through nano - silica fume and cenospheres, gels can be formed in the capillary pores of the filling slurry, reducing the capillary pores to prevent the long - term immersion of mine groundwater into the hardened slurry interior, enhancing the practicality of the curing material; 2. The branched chains formed by methallyl hydroxyethyl polyoxyethylene ether are used to improve the fluidity of the filling slurry, the branched chains of hydroxybutyl acrylate are used to inhibit the cracking of the hardened slurry, and through the polymerized high - molecular structure, the silicon - oxygen bonds and aluminum - oxygen bonds in the cementitious material are broken, releasing free - moving Si and Al ion monomers to form new silicon - aluminum - oxygen bonds or silicon - aluminum - chlorine to solidify harmful ions in the mine and avoid the leaching of harmful ions, enhancing the functionality of the curing material. By using an antifoaming agent to further reduce the capillary voids to improve the density and strength of the filling slurry, and cooperating with a penetrant to reduce the internal stress in the capillaries of the filling slurry, more gels are formed inside the capillary pores to avoid the cracking of the hardened slurry; 3. By using the fly ash after harmless treatment, the present invention can solve the problems that fly ash is difficult to apply and fills a large amount of land, and at the same time, by adding a fly ash modifier, the performance and strength of the mine filling solidification material prepared from fly ash can meet the requirements of mine filling, reduce the permeability of the filling solidification material during mine application, avoid internal water seepage caused by water penetration, and solidify harmful ions inside the mine. 4. Through the volcanic ash activity excitation effect of nano-silica fume in the modifier and the synergistic effect of the micro-aggregate filling effect of cenospheres, the compressive strength of the filling body is greatly improved. Moreover, nano-silica fume fills the tailings grading pores, and cenospheres simultaneously improve the rheology of the slurry, realizing the coexistence of "high density" and "high fluidity", breaking through the performance contradiction of traditional materials. Nano-silica fume in the modifier generates a dense C-S-H gel layer in the capillary pores, and combined with the polyoxypropylene polyoxyethylene glycerol ether of the defoamer, the bubble rate decreases, effectively blocking the infiltration of groundwater into the filling body. 5. Through the polymerization network of the stabilizer, that is, the branched chain of hydroxybutyl acrylate inhibits shrinkage and cracking. At the same time, active Si / Al ions are released by the breaking of silicon-oxygen bonds to form a gel bonding structure, ensuring that the filling body has a high strength retention rate after wet-dry cycles. Brief Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a flowchart of a preparation method of a mine filling solidification material prepared from municipal solid waste incineration fly ash according to an embodiment of the present invention. Detailed Embodiments

[0017] According to an embodiment of the present invention, a mine filling solidification material prepared from municipal solid waste incineration fly ash and a preparation method thereof are provided.

[0018] Now, the present invention will be further described in conjunction with the drawings and specific embodiments: Example 1: The mine filling solidification material prepared from municipal solid waste incineration fly ash according to an embodiment of the present invention includes the following raw materials in parts by mass: 25 - 35 parts of filling solidifying agent, 18 - 24 parts of coarse tailings, 12 - 16 parts of fine tailings, 7 - 9 parts of deionized water, 0.3 - 0.6 parts of fly ash modifier, wherein the filling solidifying agent is composed of harmless fly ash, S95 slag powder, building gypsum powder, and quicklime; Among them, the fly ash modifier is prepared by the following steps: Step 1: Add 300 g of deionized water into a stirring reactor, and then successively add 10 g of N-methylolacrylamide, 200 g of methallyl hydroxyethyl polyoxyethylene ether, 25 g of methallyl alcohol, 5 g of ammonium persulfate, and 5 g of ferrous sulfate solution. Stir at 300 rpm at room temperature for 30 minutes to obtain premix A; It should be noted that at this time, the combined ammonium persulfate and ferrous sulfate form a redox initiation system to ensure the smooth start of the free radical polymerization reaction, and can avoid chain breakage or uneven crosslinking caused by local overheating; Step 2: Heat premix A to 60 °C, and uniformly add the mixed preparation at a constant speed. The uniform addition time is 60 minutes, the temperature is set at 60 ± 2 °C, and the stirring speed is 400 rpm. The raw materials of the mixed preparation are 13 g of acrylic acid and 27 g of hydroxybutyl acrylate. When adding the mixed preparation for 30 minutes, add 2 g of stannous chloride, and continue to complete the addition of the remaining mixed preparation to obtain premix B; It should be noted that acrylic acid and hydroxybutyl acrylate are mixed and dropped into the stirrer. The dropping time is 60 minutes to finish dropping. The mixed solution of acrylic acid and hydroxybutyl acrylate is uniformly added dropwise within 60 minutes to control the monomer concentration gradient, make the polymerization reaction rate uniform, and the hydroxyl group in hydroxybutyl acrylate and Ca 2+ 、Al 3+ in the gelling material (components of the curing agent, such as mineral powder, gypsum or lime) form coordination bonds, improve the adsorption capacity of the stabilizer on the surface of cement particles, inhibit particle agglomeration, and improve the fluidity of the filling slurry; Step 3: After premix B is prepared, maintain the reaction at 60 °C for 30 minutes, then add 35 g of pentanediol, and continue to react for 60 minutes. Then transfer it to a spray dryer, set the inlet temperature at 180 °C and the outlet temperature at 80 °C, and dry to obtain a concrete stabilizer. Add the concrete stabilizer, complexing agent, defoaming agent, and penetrant into a high-speed mixer according to the mass ratio of 5.5:1.5:1.5:2 to obtain an activator; It should be noted that pentanediol is added at the end of the reaction, and its hydroxyl group reacts with the terminal free radical of the polymer to achieve active chain capping, preventing the viscosity from increasing due to continued polymerization during storage.

[0019] Step 4: Add nano-silica fume, cenosphere, and activator into a three-dimensional mixer according to the mass ratio of 1:1:2, and mix at a speed of 500 rpm for 30 minutes to obtain a fly ash modifier; The preparation method of the mine filling and solidifying material includes the following preparation steps: S1: Screen the collected municipal solid waste incineration fly ash through a vibrating screen with a screen hole of 2 - 5 mm. Place the municipal solid waste incineration fly ash after vibrating screening in a desorption device, heat it to 350 - 400 °C, and keep it for 60 minutes to remove dioxin and obtain harmless fly ash; It should be noted that according to the "Pollution Control Standard for Municipal Solid Waste Incineration" (GB18485-2014), in the flue gas discharged from waste incineration, the measured average value of dioxins needs to be controlled within 0.1 ng TEQ / m 3 , S2. Premix the building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling curing agent, where the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S3. Weigh the following raw materials by mass parts: 25-35 parts of the filling curing agent, 18-24 parts of coarse tailings, 12-16 parts of fine tailings, 7-9 parts of deionized water, and 0.3-0.6 parts of fly ash modifier; S4. Add the coarse tailings, fine tailings, filling curing agent, and fly ash modifier into a forced mixer in sequence. After dry mixing for 3 minutes, slowly add deionized water and continuously stir at 200 rpm for 10 minutes to obtain a mine filling curing material.

[0020] It should be noted that the particle size of the coarse-grained tailings is 2.36 mm, and the particle size of the fine-grained tailings is less than 0.075 mm. In the embodiment of the present invention, the particle size of the fine-grained tailings is 0.05 mm. By mixing the coarse-grained tailings and the fine-grained tailings, for example, the mixing ratio is 3:2 in the embodiment of the present invention, a closely packed structure can be formed, effectively filling the particle gaps and significantly improving the material density.

[0021] Example 2: A preparation method of a mine filling curing material, comprising the following preparation steps: S1. Screen the collected municipal solid waste incineration fly ash through a vibrating screen with a sieve hole of 2 mm, place the municipal solid waste incineration fly ash after vibrating screening in a desorption device, heat it to 400 °C, and keep it for 60 minutes to obtain harmless fly ash; S2. Premix the building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling curing agent, where the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S3. Weigh the following raw materials by mass parts: 25 parts of the filling curing agent, 18 parts of coarse tailings, 12 parts of fine tailings, 7 parts of deionized water, and 0.3 parts of fly ash modifier; S4. Add the coarse tailings, fine tailings, filling curing agent, and fly ash modifier into a forced mixer in sequence. After dry mixing for 3 minutes, slowly add deionized water and continuously stir at 200 rpm for 10 minutes to obtain a mine filling curing material; Among them, the fly ash modifier is prepared from deionized water, N-methylolacrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrant, nano-silica fume, and cenospheres. The complexing agent is a combination of diethylenetriaminepentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is sodium α-olefin sulfonate.

[0022] Example 3: A preparation method of a mine filling and solidifying material, comprising the following preparation steps: S1. Screen the collected domestic waste incineration fly ash through a vibrating screen with a sieve hole of 2 mm, place the domestic waste incineration fly ash after vibrating screening in a desorption device, heat it to 400 °C, and keep it for 60 minutes to obtain harmless fly ash; S2. Premix the building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling and solidifying agent, where the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S3. Weigh the following raw materials by mass parts: 35 parts of the filling and solidifying agent, 24 parts of coarse tailings, 16 parts of fine tailings, 9 parts of deionized water, and 0.6 part of the fly ash modifier; S4. Add the coarse tailings, fine tailings, filling and solidifying agent, and fly ash modifier to a forced mixer in sequence, dry mix for 3 minutes, then slowly add deionized water, and continuously stir at 200 rpm for 10 minutes to obtain the mine filling and solidifying material; Among them, the fly ash modifier is prepared from deionized water, N-methylolacrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrant, nano-silica fume, and cenospheres. The complexing agent is a combination of diethylenetriaminepentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is sodium α-olefin sulfonate; Example 4: A preparation method of a mine filling and solidifying material, comprising the following preparation steps: S1. Screen the collected domestic waste incineration fly ash through a vibrating screen with a sieve hole of 2 mm, place the domestic waste incineration fly ash after vibrating screening in a desorption device, heat it to 400 °C, and keep it for 60 minutes to obtain harmless fly ash; S2. Premix the building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling curing agent, where the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S3. Weigh the following raw materials by mass: 2500 kg / m 3 filling curing agent, 1800 kg / m 3 coarse tailings, 1200 kg / m 3 portion of fine tailings, 700 kg / m 3 deionized water, 30 kg / m 3 fly ash modifier; S4. Add the coarse tailings, fine tailings, filling curing agent, and fly ash modifier to a forced mixer in sequence. After dry mixing for 3 minutes, slowly add deionized water and continuously stir at 200 rpm for 10 minutes to obtain a mine filling curing material; Among them, the fly ash modifier is prepared from deionized water, N-methylolacrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrant, nano-silica fume, and cenospheres. The complexing agent is a combination of diethylenetriamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is α-olefin sulfonate; Comparative Example 1: A preparation method of a mine filling curing material, including the following preparation steps: S1. Screen the collected domestic waste incineration fly ash through a vibrating screen with a screen hole of 2 mm. Place the domestic waste incineration fly ash after vibrating screening in a desorption device, heat it to 400 °C, and keep it for 60 minutes to obtain harmless fly ash; S2. Premix the building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling curing agent, where the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S3. Weigh the following raw materials by mass: 2500 kg / m 3 filling curing agent, 1800 kg / m 3 coarse tailings, 1200 kg / m 3 portion of fine tailings, 700 kg / m 3 deionized water; S4. Add the coarse tailings, fine tailings, and filling curing agent to a forced mixer in sequence. After dry mixing for 3 minutes, slowly add deionized water and continuously stir at 200 rpm for 10 minutes to obtain a mine filling curing material; Comparative Example 2: Preparation method of mine filling and solidifying material, comprising the following preparation steps: S1. Screen the collected domestic waste incineration fly ash through a vibrating screen with a sieve hole of 2 mm, place the domestic waste incineration fly ash after vibrating screening in a desorption device, heat it to 400 °C, and keep it for 60 minutes to obtain harmless fly ash; S2. Premix building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling and solidifying agent, wherein the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S3. Weigh the following raw materials by mass parts: 2500 kg / m 3 Filling and solidifying agent, 3000 kg / m 3 Coarse tailings, 700 kg / m 3 Deionized water, 30 kg / m 3 Fly ash modifier; S4. Add the coarse tailings, filling and solidifying agent, and fly ash modifier to a forced mixer in sequence, dry mix for 3 minutes, then slowly add deionized water, and continuously stir at 200 rpm for 10 minutes to obtain the mine filling and solidifying material; Among them, the fly ash modifier is prepared from deionized water, N-methylolacrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrant, nano-silica fume, and cenospheres. The complexing agent is a combination of diethylenetriamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is α-olefin sulfonate; Comparative Example 3: Preparation method of mine filling and solidifying material, comprising the following preparation steps: S1. Premix building gypsum powder and quicklime in a mass ratio of 1:1 for 5 minutes, then add the untreated domestic waste incineration fly ash and S95 slag powder and continue to mix at 35 rpm for 20 minutes to obtain a filling and solidifying agent, wherein the mass ratio of the untreated domestic waste incineration fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1; S2. Weigh the following raw materials by mass parts: 2500 kg / m 3 Filling and solidifying agent, 1800 kg / m 3 Coarse tailings, 1200 kg / m 3 parts of fine tailings, 700 kg / m 3 Deionized water, 30 kg / m 3 Fly ash modifier; S3. Add coarse tailings, fine tailings, filling curing agent, and fly ash modifier into a forced mixer in sequence. After dry mixing for 3 minutes, slowly add deionized water and continuously stir at 200 rpm for 10 minutes to obtain mine filling curing material; Among them, the fly ash modifier is prepared from deionized water, N-methylolacrylamide, methallyl hydroxyethyl polyoxyethylene ether, methallyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrant, nano-silica fume, and cenosphere. The complexing agent is a combination of diethylenetriamine pentaacetic acid and sodium nitrilotriacetate. The defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is α-olefin sulfonate; Experimental Example 1: Conduct fluidity test, compressive strength test, Pb leaching concentration test, and impermeability test on the mine filling curing materials obtained in Example 4 and Comparative Example 1 respectively. The test results are shown in Table 1: Table 1: Index test table of mine filling mortar before and after adding fly ash modifier

[0023] It can be seen from Table 1 that Comparative Example 1 lacks the "micro ball bearing" effect of cenosphere in the modifier, resulting in an increase in internal friction and a decrease in fluidity. The lack of nano-silica fume to stimulate pozzolanic activity leads to a delay in early hydration reaction, and the dense structure of C-S-H gel is not formed, resulting in limited strength improvement. The water seepage channels are not filled, and there is no complexing agent to solidify heavy metals, resulting in excessive leaching. Before adding the modifier, the 28-day strength of the filling slurry is 1.02 Mpa, which is lower than 1.5 Mpa, and the fluidity is low, making it difficult to be applied in the filling mine. After using the fly ash modifier in the mine filling mortar, the fluidity, strength at different ages, and impermeability of the mortar are significantly improved, indicating that the application of the fly ash modifier in mine filling can improve the filling efficiency and reduce the water seepage in mine filling; Conduct fluidity test, compressive strength test, and impermeability test on the mine filling curing materials obtained in Example 4 and Comparative Example 2 respectively. The test results are shown in Table 2: Table 2: Index test table of mine filling mortar before and after adding fine tailings

[0024] It can be seen from Table 2 that the lack of fine tailings in Comparative Example 2 leads to an increase in the viscosity of the slurry, the unfilled gaps between coarse sands by fine sands, and a high porosity connectivity and a decline in impermeability; Conduct dioxin residue test, fluidity test, compressive strength test, and Pb leaching concentration test on the mine filling curing materials obtained in Example 4 and Comparative Example 3 respectively. The test results are shown in Table 3: Table 3: Index test table of mine filling mortar before and after fly ash treatment

[0025] It can be seen from Table 3 that in Comparative Example 2, the fly ash was not detoxified, resulting in toxicity residue. Chloride ions in the untreated fly ash inhibited the hydration reaction, increasing the compressive strength. Agglomeration of the untreated fly ash particles led to a decrease in fluidity, and the heavy metals in the untreated fly ash were not stabilized.

[0026] Among them, for the fluidity test, referring to "GB / T 2419-2005 Test Method for Fluidity of Cement Mortar", the mixed slurry was filled into a truncated conical mold. The upper diameter of the truncated conical mold was 70 mm, the lower diameter was 100 mm, and the height was 60 mm. The mold was vertically lifted to allow the slurry to flow and spread freely, and the diameter after spreading was measured, and the average value in the vertical direction was taken, with the unit of mm. For the compressive strength test, referring to "GB / T 17671-1999 Test Method for Strength of Cement Mortar", the slurry was injected into a triple mold of 40 mm×40 mm×160 mm and vibrated densely. The strengths at 3 d, 7 d, and 28 d were respectively tested at a temperature of 20±1°C and a humidity of ≥95%. A press was used to load at a rate of 2400±200 N / s, and the failure load was recorded to calculate the compressive strength. For the impermeability test, referring to "GB / T 23440-2009 Inorganic Waterproof Plugging Materials", cylindrical specimens with a diameter of 80 mm and a height of 30 mm were prepared and cured under standard conditions for 28 d. The specimens were installed in an impermeability tester. The water pressure started from 0.1 MPa and increased by 0.1 MPa every 1 hour, and the pressure value when the specimen leaked water was recorded as the impermeability strength. For the Pb leaching concentration test, in accordance with "HJ / T299-2007 Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid-Nitric Acid Method", the test block was crushed to a particle size of <9.5 mm, and the leaching agent with a liquid-solid ratio of 10:1 and a pH of 3.20±0.05 was added. After turning and oscillating for 18 hours, it was filtered, and the Pb concentration was measured by an inductively coupled plasma mass spectrometer. In the test for dioxin residue detection, 1 g of the test block powder was taken, and after Soxhlet extraction and purification by a multi-layer silica gel column, it was analyzed by a combination of high-resolution gas chromatography (HRGC) and high-resolution mass spectrometry (HRMS). It can be seen from Tables 1 to 3 that Comparative Example 1 shows that through the activation of the activity of nano-silica fume and the optimization of the gradation of cenospheres, the modifier increased the strength by 190% and the impermeability by 167%, and effectively solidified heavy metals. Before adding the modifier, the 28-day strength of the filling slurry was 1.02 MPa, lower than 1.5 MPa, and the fluidity was relatively low at 130 mm. Such low fluidity made the transportation and filling process of the slurry in the mine extremely difficult, and it was impossible to achieve a uniform and efficient filling effect, greatly limiting its practical application in filling mines. After applying the filling curing agent and modifier to the mine filling mortar, the fluidity of the mortar is greatly improved, enabling it to flow and spread more smoothly in the mine roadway, ensuring that every space requiring filling can be evenly covered, effectively enhancing the speed and quality of the filling operation. Comparative example 2 proves that the combination of coarse-grained tailings and fine-grained tailings is the key to dense packing. Single-sized tailings lead to an increase in porosity and a decrease in strength. Comparative example 3 shows that although the detoxified fly ash can partially replace the cementitious material, the residual dioxin exceeds the standard by 8 times, and the heavy metal leaching concentration exceeds the national standard limit by 4 times, with significant environmental risks.

[0027] In summary, in the present invention, by adding a fly ash modifier to the filler curing agent prepared from harmless fly ash, under the complexation solubilization effect, more hydrated calcium silicate is formed during the hydration process of the fly ash modifier in the filler curing agent, promoting the hydration reaction of mineral powder and harmless fly ash, and curing the difficult-to-treat chloride ions in the fly ash. By providing active silicon ions and aluminum ions through nano-silica fume and cenospheres, gels can be formed in the capillary pores of the filling slurry, reducing the capillary pores to prevent the long-term immersion of mine groundwater into the hardened slurry interior, enhancing the practicality of the curing material; The branched chain formed by methallyl hydroxyethyl polyoxyethylene ether is used to improve the fluidity of the filling slurry, the branched chain of hydroxybutyl acrylate is used to inhibit the cracking of the hardened slurry, and through the polymerized polymer structure, the silicon-oxygen bond and aluminum-oxygen bond in the cementitious material are broken, releasing free-moving Si and AI ion monomers to form new silicon-aluminum-oxygen bonds or silicon-aluminum chloride to solidify harmful ions in the mine and avoid the leaching of harmful ions, enhancing the functionality of the curing material. By using an antifoaming agent to further reduce the capillary voids to improve the compactness and strength of the filling slurry, and cooperating with a penetrant, the internal stress in the capillary of the filling slurry can be reduced, forming more gels inside the capillary pores to avoid the cracking of the hardened slurry.

[0028] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. The mine filling and solidifying material prepared from municipal solid waste incineration fly ash is characterized in that It includes raw materials in the following parts by mass: 25 - 35 parts of filling curing agent, 18 - 24 parts of coarse tailings, 12 - 16 parts of fine tailings, 7 - 9 parts of deionized water, 0.3 - 0.6 part of fly ash modifier, wherein the filling curing agent is composed of harmless fly ash, S95 slag powder, building gypsum powder, and quicklime; Among them, the fly ash modifier is prepared by the following steps: Step 1: Add deionized water to a stirring reaction kettle, and then successively add N - hydroxymethyl acrylamide, methyl allyl hydroxyethyl polyoxyethylene ether, methyl allyl alcohol, ammonium persulfate, and ferrous sulfate solution, and stir at room temperature for 30 minutes to obtain premix A; Step 2: Heat premix A to 60 °C and uniformly dropwise add a mixed preparation, wherein the raw materials of the mixed preparation are acrylic acid and hydroxybutyl acrylate. When adding the mixed preparation for 30 minutes, add stannous chloride and continue to complete the dropping of the remaining mixed preparation to obtain premix B; Step 3: After premix B is prepared, maintain the reaction at 60 °C for 30 minutes, then add pentanediol and continue to react for 60 minutes, and then transfer it to a spray dryer. Set the inlet temperature at 180 °C and the outlet temperature at 80 °C to dry and obtain a concrete stabilizer. Add the concrete stabilizer, complexing agent, defoaming agent, and penetrant to a high - speed mixer and mix to obtain an activator; Step 4: Add nano - silica fume, cenosphere, and activator to a three - dimensional mixer and mix to obtain a fly ash modifier, which can improve strength and impermeability and effectively solidify heavy metals.

2. The mine filling and solidifying material prepared from municipal solid waste incineration fly ash according to claim 1, characterized in that, In Step 2, the mass ratio of acrylic acid to hydroxybutyl acrylate used is 13:27, the total dropping time of the mixed preparation is 60 minutes, the temperature is set at 60 ± 2 °C, and the stirring speed is 400 rpm.

3. The mine filling and solidifying material prepared from municipal solid waste incineration fly ash according to claim 1, wherein In Steps 1, 2, and 3, the mass ratio of deionized water, N - hydroxymethyl acrylamide, methyl allyl hydroxyethyl polyoxyethylene ether, methyl allyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, and pentanediol is 300:10:200:25:5:5:13:27:2:

35.

4. The mine filling and solidifying material prepared from municipal solid waste incineration fly ash according to claim 1, characterized in that, In Step 1, the concentration of ferrous sulfate used is 0.1%, and the stirring speed at room temperature is 300 rpm.

5. The mine filling and solidifying material prepared from municipal solid waste incineration fly ash according to claim 1, characterized in that, In step 4, the mass ratio of nano-silica fume, cenospheres, and activator used is 1:1:2, the mixing time is 30 minutes, the rotation speed is set at 500 rpm, the silica content of nano-silica fume > 90%, the specific surface area of nano-silica fume > 200 m 2 / g, the silica content of cenospheres > 60%, the alumina content > 30%, and the density of cenospheres < 0.7 cm 2 / g.

6. The mine filling and solidifying material prepared from municipal solid waste incineration fly ash according to claim 1, characterized in that, In Step 3, the mass ratio of the concrete stabilizer, complexing agent, defoaming agent, and penetrant is 5.5:1.5:1.5:2, wherein the complexing agent is one or two of diethylenetriamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is one or two of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylene amine ether, or polyoxypropylene polyoxyethylene glycerol ether, and the penetrant is one or two of isooctyltriethoxysilane, secondary alkyl sulfate ester sodium, or α - olefin sulfonate sodium.

7. A preparation method of a mine filling and solidifying material according to any one of claims 1-6, characterized in that, It includes the following preparation steps: S1: Screen the collected municipal solid waste incineration fly ash through a vibrating screen, place the municipal solid waste incineration fly ash after the vibrating screen in a desorption device, heat it to 350 - 400 °C for 60 minutes to remove dioxin and obtain harmless fly ash; S2: Premix building gypsum powder and quicklime for 5 minutes, then add harmless fly ash and S95 slag powder and continue to mix for 20 minutes to obtain a filling curing agent; S3: Weigh the following raw materials according to the parts by mass: 25 - 35 parts of filling and solidifying agent, 18 - 24 parts of coarse tailings, 12 - 16 parts of fine tailings, 7 - 9 parts of deionized water, 0.3 - 0.6 parts of fly ash modifier; S4. Add the coarse tailings, fine tailings, filling and solidifying agent, and fly ash modifier into a forced mixer in sequence. After dry - mixing for 3 minutes, slowly add deionized water and continuously stir to obtain the mine filling and solidifying material.

8. The preparation method of the mine filling and solidifying material according to claim 7, wherein In S2, the mass ratio of the harmless fly ash, S95 slag powder, building gypsum powder, and quicklime is 9:9:1:1, and the stirring speed is 35 rpm.

9. The preparation method of the mine filling and solidifying material according to claim 7, wherein In S1, the sieve holes of the vibrating screen are 2 - 5 mm, and the continuous stirring time in S4 is 8 - 10 minutes, and the stirring speed is 200 rpm.

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