Mine filling solidified material prepared from domestic waste incineration fly ash and preparation method thereof

Abstract

The application discloses a mine filling solidified material prepared from domestic waste incineration fly ash and a preparation method thereof, and relates to the technical field of waste recycling and reuse, and comprises the following raw materials in mass fractions: 25-35 parts of filling solidified 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. On the basis of fly ash harmless treatment, the performance and strength of the filling slurry are improved by adding the fly ash modifier, so that the fly ash can be effectively applied in mine filling, the fly ash landfill and secondary pollution problems are reduced, and under the complex solubilization effect, more calcium silicate hydrate is formed in the hydration process of the fly ash modifier in the filling solidified agent, and the hydration reaction of the mineral powder and the harmless fly ash is promoted. Through the volcanic ash activity excitation effect of nano silica ash and the micro aggregate filling effect of the floating beads, the compressive strength of the filling body is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste recycling, in particular to a mine filling solidified material prepared from municipal solid waste incineration fly ash and a preparation method thereof. BACKGROUND

[0002] Fly ash is a substance collected by heat recovery and flue gas purification system after waste incineration. The amount of fly ash generated by incineration of waste is related to the type of waste, incineration equipment and treatment process. Generally, it is 3%-5% of the total amount of incinerated waste. The main substances and heavy metals have high content. This part of heavy metals and organic compounds has very high leaching toxicity, which increases the difficulty of disposing of pollutants generated by fly ash. If it is discharged into the environment without treatment, it is easy to cause secondary pollution to the atmosphere and water body;

[0003] The current fly ash treatment method is mainly landfill treatment. This treatment method easily occupies a large amount of land resources and needs to increase a large amount of infrastructure cost. Long-term landfill treatment will cause groundwater pollution. At the same time, due to the increase of fly ash production, the site for landfill is becoming less and less. The existing fly ash treatment technology has the problems of low practicability and functionality.

[0004] In view of the problems in the related art, no effective solution has been proposed so far. SUMMARY

[0005] In view of the problems in the related art, the present application proposes a mine filling solidified material prepared from municipal solid waste incineration fly ash and a preparation method thereof to overcome the above technical problems.

[0006] To this end, the specific technical solutions adopted by the present application are as follows:

[0007] The mine filling solidified material prepared from municipal solid waste incineration fly ash comprises the following raw materials in mass fraction: 25-35 parts of filling solidified 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. The filling solidified agent is composed of harmless fly ash, S95 mineral powder, building gypsum powder and quicklime.

[0008] The fly ash modifier is prepared by the following steps:

[0009] Step 1, deionized water is added into a stirring reaction kettle, and then N-hydroxymethyl acrylamide, methyl alkylene butyl hydroxyethyl polyoxyethylene ether, methyl alkylene alcohol, ammonium persulfate and ferrous sulfate solution are added in sequence. Stir at room temperature for 30 minutes to obtain premix A;

[0010] Step 2, the premix A is heated to 60℃, and the mixed preparation is added at a constant speed, wherein the raw materials of the mixed preparation are acrylic acid and hydroxybutyl acrylate, at 30 minutes of adding the mixed preparation, stannous chloride is added, and the remaining mixed preparation is added to complete the reaction, to obtain premix B;

[0011] Step 3, after the preparation of premix B is completed, the reaction is maintained at 60℃ for 30 minutes, then pentanediol is added, and the reaction is continued for 60 minutes, then it is transferred to a spray dryer, the inlet temperature is set to 180℃, and the outlet temperature is set to 80℃, the concrete stabilizer is dried to obtain a concrete stabilizer, the concrete stabilizer, the complexing agent, the defoaming agent, and the penetrating agent are added to a high-speed mixer, and the mixture is mixed to obtain an activator.

[0012] Step 4, the nano-silica, the floating bead, and the activator are added to a three-dimensional mixer, and the mixture is mixed to obtain a fly ash modifier, which improves the strength and impermeability and effectively solidifies heavy metals.

[0013] As a preferred embodiment, the mass ratio of acrylic acid to hydroxybutyl acrylate used in step 2 is 13:27, the total time for adding the mixed preparation at a constant speed is 60 minutes, the temperature is set to 60±2℃, and the stirring speed is 400 rpm.

[0014] As a preferred embodiment, the mass ratio of deionized water, N-hydroxymethyl acrylamide, methyl alkyl butyl hydroxyethyl polyoxyethylene ether, methyl alkyl 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.

[0015] As a preferred embodiment, the concentration of ferrous sulfate used in step 1 is 0.1%, and the stirring speed at room temperature is 300 rpm.

[0016] As a preferred embodiment, the mass ratio of nano-silica, floating bead, and activator used in step 4 is 1:1:2, the mixing time is 30 minutes, the stirring speed is set to 500 rpm, the silicon dioxide content of the nano-silica is >90%, the specific surface area of the nano-silica is >200m 2 / g, the silicon dioxide content of the floating bead is >60%, the aluminum oxide content of the floating bead is >30%, and the density of the floating bead is <0.7cm 2 / g.

[0017] As a preferred embodiment, the mass ratio of the concrete stabilizer, the complexing agent, the defoaming agent and the penetrating agent in step 3 is 5.5:1.5:1.5:2, wherein the complexing agent is one or both of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is one or both of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylamine ether or polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is one or both of isooctyl triethoxysilane, sodium alkyl sulfate and sodium a-alkenyl sulfonate.

[0018] The application discloses a preparation method of a mine filling solidified material.

[0019] S1, the collected household garbage incineration fly ash is screened through a vibrating screen, and the household garbage incineration fly ash after the vibrating screen is placed in a desorption device and heated to 350-400 DEG C for 60 minutes to remove dioxin and obtain harmless fly ash;

[0020] S2, the building gypsum powder and the quicklime are premixed for 5 minutes, then the harmless fly ash and the S95 mineral powder are continuously mixed for 20 minutes to obtain a filling solidified agent;

[0021] S3, the following raw materials are weighed according to mass fractions: 25-35 parts of the filling solidified 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;

[0022] S4, the coarse tailings, the fine tailings, the filling solidified agent and the fly ash modifier are sequentially added into a forced stirrer, deionized water is slowly added after dry mixing for 3 minutes, and continuous stirring is carried out to obtain the mine filling solidified material.

[0023] As a preferred embodiment, the mass ratio of the harmless fly ash, the S95 mineral powder, the building gypsum powder and the quicklime in S2 is 9:9:1:1, and the stirring speed is 35 rpm.

[0024] As a preferred embodiment, the sieve hole of the vibrating screen in S1 is 2-5 mm, and the continuous stirring time in S4 is 8-10 minutes, and the stirring speed is 200 rpm.

[0025] The application has the following beneficial effects:

[0026] 1. This invention adds a fly ash modifier to the filler curing agent prepared from harmless fly ash. Under the complexation and solubilization effect, the fly ash modifier forms more hydrated calcium silicate during the hydration process of the filler curing agent, promotes the hydration reaction of mineral powder and harmless fly ash, and solidifies the difficult-to-treat chloride ions in fly ash. The active silicon ions and aluminum ions provided by nano silica fume and cenospheres can form a gel in the capillary pores of the filling slurry, reduce capillary porosity, and prevent long-term soaking of mine groundwater into the hardened slurry, thereby enhancing the practicality of the curing material.

[0027] 2. This invention improves the flowability of the filling slurry by using branched chains formed by methyl allyl hydroxyethyl polyoxyethylene ether, inhibits cracking of the hardened slurry by using hydroxybutyl acrylate branched chains, and breaks the silicon-oxygen and aluminum-oxygen bonds in the cementitious material through the polymer structure formed by polymerization, releasing freely moving Si and Al ion monomers to form new silicon-aluminum-oxygen bonds or silicon-aluminum chloride, thereby solidifying harmful ions in the mine and preventing their leaching, thus enhancing the functionality of the solidified material. The use of defoamers further reduces capillary porosity, thereby improving the density and strength of the filling slurry. Combined with penetrants, it can reduce the internal stress of the capillaries in the filling slurry, allowing more gel to form inside the capillary pores and preventing cracking of the hardened slurry.

[0028] 3. By using fly ash that has been rendered harmless, this invention can solve the problem of fly ash being difficult to apply and occupying a large amount of land. At the same time, by adding fly ash modifier, the performance and strength of the mine filling and solidification material prepared by fly ash can meet the requirements of mine filling, reduce the permeability of the filling and solidification material when applied in the mine, avoid water penetration and internal water seepage, and solidify harmful ions inside the mine.

[0029] 4. This invention utilizes the volcanic ash activation effect of nano-silica fume in the modifier, which synergistically enhances the micro-aggregate filling effect of cenospheres, thereby significantly improving the compressive strength of the filling body. Furthermore, the nano-silica fume fills the gradation pores of the tailings sand, while the cenospheres simultaneously improve the rheological properties of the slurry, achieving a coexistence of "high density" and "high fluidity," thus overcoming the contradictions in the performance of traditional materials. The nano-silica fume in the modifier generates a dense CSH gel layer within the capillary pores, which, combined with the polyoxypropylene polyoxyethylene glycerol ether of the defoamer, reduces the bubble rate and effectively prevents groundwater from seeping into the interior of the filling body.

[0030] 5. This invention inhibits shrinkage cracking through the polymer network of the stabilizer, namely the branched chain of hydroxybutyl acrylate, and releases active Si / Al ions through the breaking of silicon-oxygen bonds to generate a gel-bonded structure, ensuring that the filling material has a high strength retention rate after wet-dry cycles. Attached Figure Description

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0032] Figure 1 is a flow chart of a preparation method of a mine filling solidified material prepared from domestic waste incineration fly ash according to the embodiment of the present application. DETAILED DESCRIPTION

[0033] According to the embodiment of the present application, a mine filling solidified material prepared from domestic waste incineration fly ash and a preparation method are provided.

[0034] The present application will be further described in conjunction with the drawings and specific embodiments:

[0035] Embodiment 1:

[0036] The mine filling solidified material prepared from domestic waste incineration fly ash according to the embodiment of the present application comprises the following raw materials in mass fraction: 25-35 parts of filling solidified 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, wherein the filling solidified agent is composed of harmless fly ash, S95 mineral powder, building gypsum powder, and quicklime.

[0037] The fly ash modifier is prepared by the following steps:

[0038] Step 1, 300g of deionized water is added to a stirring reaction kettle, and then 10g of N-methylol acrylamide, 200g of methyl alkenyl butyl hydroxyethyl polyoxyethylene ether, 25g of methyl alkenyl alcohol, 5g of ammonium persulfate, and 5g of ferrous sulfate solution are sequentially added, and stirred at 300rpm at room temperature for 30 minutes to obtain premix A;

[0039] It should be noted that the combined ammonium persulfate and ferrous sulfate form an oxidation-reduction initiation system at this time, which ensures the smooth start of the free radical polymerization reaction and can avoid chain scission or uneven crosslinking caused by local overheating;

[0040] Step 2, the premix A is heated to 60℃, and the mixed preparation is added at a uniform speed, the uniform speed dropping time is 60 minutes, the temperature is set to 60±2℃, and the stirring speed is 400rpm, wherein the raw materials of the mixed preparation are 13g of acrylic acid and 27g of hydroxybutyl acrylate, 2g of stannous chloride is added when the mixed preparation is dropped for 30 minutes, and the remaining mixed preparation is continuously added to obtain premix B;

[0041] It should be noted that the acrylic acid and hydroxybutyl acrylate are mixed and dropped into the stirrer, the dropping time is 60 minutes, the acrylic acid and hydroxybutyl acrylate mixture is dropped at a uniform speed within 60 minutes, the monomer concentration gradient is controlled, the polymerization reaction rate is uniform, and the hydroxyl group in the hydroxybutyl acrylate forms a coordination bond with Ca 2+ 、Al 3+ Form a coordination bond to improve the adsorption capacity of the stabilizer on the surface of the cement particles, inhibit particle agglomeration, and improve the flowability of the filling material slurry;

[0042] Step 3, after the preparation of premix B is completed, maintain 60℃ reaction for 30 minutes, then add 35g pentanediol, and continue to react for 60 minutes, then transfer to a spray dryer, set the inlet temperature to 180℃, and the outlet temperature to 80℃, dry to obtain a concrete stabilizer, mix the concrete stabilizer, complexing agent, defoaming agent, and penetrating agent in a high-speed mixer according to the mass ratio of 5.5:1.5:1.5:2, and mix to obtain an activator;

[0043] It should be noted that pentanediol is added at the end of the reaction, and the hydroxyl group reacts with the terminal free radical of the polymer to achieve active chain termination, preventing continued polymerization during storage and causing viscosity to rise.

[0044] Step 4, add nano-silica ash, floating beads, and activator to a three-dimensional mixer according to the mass ratio of 1:1:2, mix at a speed of 500 rpm for 30 minutes to obtain a fly ash modifier;

[0045] The preparation method of the mine filling solidification material comprises the following preparation steps:

[0046] S1, screen the collected household waste incineration fly ash through a vibrating screen with a screen hole of 2-5mm, place the household waste incineration fly ash after the vibrating screen in a desorption device, heat to 350-400℃, and maintain for 60 minutes to remove dioxins, and obtain harmless fly ash;

[0047] It should be noted that according to the "Household Waste Incineration Pollution Control Standard" (GB18485-2014), the average value of dioxins in waste incineration flue gas needs to be controlled at 0.1 ngTEQ / m 3 ,

[0048] S2, premix the building gypsum powder and quicklime according to the mass ratio of 1:1 for 5 minutes, then add the harmless fly ash and S95 mineral powder and continue to mix at 35 rpm for 20 minutes to obtain a filling solidification agent, wherein the mass ratio of harmless fly ash, S95 mineral powder, building gypsum powder, and quicklime is 9:9:1:1;

[0049] S3, the following raw materials are taken by mass fraction: 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;

[0050] S4, the coarse tailings, fine tailings, filling curing agent and fly ash modifier are sequentially added to a forced mixer, dry mixing for 3 minutes, then slowly adding deionized water, continuously stirring at 200 rpm for 10 minutes to obtain the mine filling and curing material.

[0051] It should be noted that the particle size of the coarse particle size tailings is 2.36 mm, and the particle size of the fine particle size tailings is less than 0.075 mm, and in the embodiment of the present application, the particle size of the fine particle size tailings is 0.05 mm, and by matching the coarse particle size tailings and the fine particle size tailings, for example, in the embodiment of the present application, the ratio is 3:2, a close-packed structure can be formed, the inter-particle gap can be effectively filled, and the material density can be significantly improved.

[0052] Example 2:

[0053] The preparation method of the mine filling and curing material comprises the following preparation steps:

[0054] S1, the collected municipal solid waste incineration fly ash is screened through a vibrating screen with a mesh size of 2 mm, and the municipal solid waste incineration fly ash after the vibrating screen is placed in a desorption device, heated to 400 DEG C, and maintained for 60 minutes to obtain harmless fly ash;

[0055] S2, the building gypsum powder and quicklime are premixed at a mass ratio of 1:1 for 5 minutes, then the harmless fly ash and S95 mineral powder are added and mixed at 35 rpm for 20 minutes to obtain the filling curing agent, wherein the mass ratio of the harmless fly ash, S95 mineral powder, building gypsum powder and quicklime is 9:9:1:1;

[0056] S3, the following raw materials are taken by mass fraction: 25 parts of 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;

[0057] S4, the coarse tailings, fine tailings, filling curing agent and fly ash modifier are sequentially added to a forced mixer, dry mixing for 3 minutes, then slowly adding deionized water, continuously stirring at 200 rpm for 10 minutes to obtain the mine filling and curing material.

[0058] The fly ash modifier is prepared from deionized water, N-hydroxymethyl acrylamide, methyl alkylene butyl hydroxyethyl polyoxyethylene ether, methyl alkylene alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrating agent, nano silica fume and floating bead, wherein the complexing agent is a combination of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is a-sodium alkene sulfonate.

[0059] Example 3:

[0060] The preparation method of the mine filling solidified material comprises the following preparation steps:

[0061] S1, the collected household garbage incineration fly ash is screened through a vibrating screen with a mesh size of 2mm, and the household garbage incineration fly ash after the vibrating screen is placed in a desorption device and heated to 400℃ for 60 minutes to obtain harmless fly ash;

[0062] S2, the building gypsum powder and the quicklime are premixed at a mass ratio of 1:1 for 5 minutes, then the harmless fly ash and the S95 mineral powder are continuously mixed at 35 rpm for 20 minutes to obtain a filling solidified agent, wherein the mass ratio of the harmless fly ash, the S95 mineral powder, the building gypsum powder and the quicklime is 9:9:1:1;

[0063] S3, the following raw materials are weighed according to the mass fraction: 35 parts of the filling solidified agent, 24 parts of the coarse tailings, 16 parts of the fine tailings, 9 parts of the deionized water and 0.6 parts of the fly ash modifier;

[0064] S4, the coarse tailings, the fine tailings, the filling solidified agent and the fly ash modifier are sequentially added to a forced mixer, dry-mixed for 3 minutes, then the deionized water is slowly added, and stirring is continuously carried out at 200 rpm for 10 minutes to obtain a mine filling solidified material;

[0065] The fly ash modifier is prepared from deionized water, N-hydroxymethyl acrylamide, methyl alkene butyl hydroxyethyl polyoxyethylene ether, methyl alkene propyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, a complexing agent, a defoaming agent, a penetrating agent, nano silica fume and floating beads, wherein the complexing agent is a combination of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is a-sodium alkene sulfonate;

[0066] Example 4:

[0067] The preparation method of the mine filling solidified material comprises the following preparation steps:

[0068] S1, the collected household garbage incineration fly ash is screened through a vibrating screen with a mesh size of 2mm, and the household garbage incineration fly ash after the vibrating screen is placed in a desorption device and heated to 400℃ for 60 minutes to obtain harmless fly ash;

[0069] S2, the building gypsum powder and the quicklime are premixed at a mass ratio of 1:1 for 5 minutes, then the harmless fly ash and the S95 mineral powder are continuously mixed at 35 rpm for 20 minutes to obtain a filling solidified agent, wherein the mass ratio of the harmless fly ash, the S95 mineral powder, the building gypsum powder and the quicklime is 9:9:1:1;

[0070] S3, the following raw materials are taken by mass fraction: 2500 kg / m 3 filling curing agent, 1800 kg / m 3 coarse tailings, 1200 kg / m 3 fine tailings, 700 kg / m 3 deionized water, 30 kg / m 3 fly ash modifier;

[0071] S4, the coarse tailings, fine tailings, filling curing agent, fly ash modifier are sequentially added to the forced mixer, dry mixing for 3 minutes, then slowly adding deionized water, continuously stirring at 200 rpm for 10 minutes to obtain mine filling curing material;

[0072] The fly ash modifier is prepared from deionized water, N-hydroxymethyl acrylamide, methyl alkyl butyl hydroxyethyl polyoxyethylene ether, methyl allyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrating agent, nano silica fume and floating bead, wherein the complexing agent is a combination of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is a-sodium alkyl sulfonate.

[0073] Comparative Example 1:

[0074] The preparation method of mine filling curing material comprises the following preparation steps:

[0075] S1, the collected household garbage incineration fly ash is screened through a vibrating screen with a mesh size of 2 mm, and the household garbage incineration fly ash after the vibrating screen is placed in a desorption device and heated to 400℃ for 60 minutes to obtain harmless fly ash;

[0076] S2, the building gypsum powder and quicklime are premixed at a mass ratio of 1:1 for 5 minutes, then the harmless fly ash and S95 mineral powder are added and mixed at 35 rpm for 20 minutes to obtain a filling curing agent, wherein the mass ratio of harmless fly ash, S95 mineral powder, building gypsum powder and quicklime is 9:9:1:1;

[0077] S3, the following raw materials are taken by mass fraction: 2500 kg / m 3 filling curing agent, 1800 kg / m 3 coarse tailings, 1200 kg / m 3 fine tailings, 700 kg / m 3 deionized water;

[0078] S4, the coarse tailings, fine tailings, filling curing agent are sequentially added to the forced mixer, dry mixing for 3 minutes, then slowly adding deionized water, continuously stirring at 200 rpm for 10 minutes to obtain mine filling curing material;

[0079] Comparative Example 2:

[0080] The preparation method of the mine filling solidified material comprises the following preparation steps:

[0081] S1, the collected household garbage incineration fly ash is screened through a vibrating screen with a mesh size of 2 mm, and the household garbage incineration fly ash after the vibrating screen is placed in a desorption device and heated to 400 DEG C for 60 minutes to obtain a harmless fly ash;

[0082] S2, the building gypsum powder and the quicklime are premixed at a mass ratio of 1:1 for 5 minutes, then the harmless fly ash and the S95 mineral powder are continuously mixed at 35 rpm for 20 minutes to obtain a filling solidified agent, wherein the mass ratio of the harmless fly ash, the S95 mineral powder, the building gypsum powder and the quicklime is 9:9:1:1;

[0083] S3, the following raw materials are weighed according to the mass fraction: 2500 kg / m 3 filling solidified agent, 3000 kg / m 3 coarse tailings, 700 kg / m 3 deionized water, 30 kg / m 3 fly ash modifier;

[0084] S4, the coarse tailings, the filling solidified agent and the fly ash modifier are sequentially added to a forced mixer, dry mixed for 3 minutes, then the deionized water is slowly added, and stirred at 200 rpm for 10 minutes to obtain a mine filling solidified material;

[0085] The fly ash modifier is prepared from deionized water, N-hydroxymethyl acrylamide, methyl alkyl butyl hydroxyethyl polyoxyethylene ether, methyl alkyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrating agent, nano silica fume and floating bead, wherein the complexing agent is a combination of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is a-sodium alkyl sulfonate;

[0086] Comparative Example 3:

[0087] The preparation method of the mine filling solidified material comprises the following preparation steps:

[0088] S1, the building gypsum powder and the quicklime are premixed at a mass ratio of 1:1 for 5 minutes, then the harmless fly ash and the S95 mineral powder are continuously mixed at 35 rpm for 20 minutes to obtain a filling solidified agent, wherein the mass ratio of the harmless fly ash, the S95 mineral powder, the building gypsum powder and the quicklime is 9:9:1:1;

[0089] S2, the following raw materials are weighed according to the mass fraction: 2500 kg / m 3Filling solidifying agent, 1800kg / m 3 Coarse tailings, 1200kg / m 3 Fine tailings, 700kg / m 3 Deionized water, 30kg / m 3 Fly ash modifier;

[0090] S3, the coarse tailings, fine tailings, filling solidifying agent, fly ash modifier are sequentially added into the forced mixer, dry mixing for 3 minutes, then slowly adding deionized water, continuously stirring at 200rpm for 10 minutes to obtain the mine filling solidifying material;

[0091] The fly ash modifier is prepared from deionized water, N-hydroxymethyl acrylamide, methyl alkyl butyl hydroxyethyl polyoxyethylene ether, methyl allyl alcohol, ammonium persulfate, ferrous sulfate solution, acrylic acid, hydroxybutyl acrylate, stannous chloride, pentanediol, complexing agent, defoaming agent, penetrating agent, nano silica ash and floating bead, wherein the complexing agent is a combination of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is a-sodium alkyl sulfonate.

[0092] Experimental example 1:

[0093] The mine filling solidifying materials obtained in example 4 and comparative example 1 are respectively subjected to flowability test, compressive strength test, Pb leaching concentration test and impermeability test, and the test results are shown in Table 1:

[0094] Table 1: Index test table of mine filling sand mortar before and after adding fly ash modifier

[0095]

[0096] From Table 1, it can be seen that comparative example 1 lacks the "micro ball bearing" effect of the floating bead in the modifier, the internal friction increases to reduce the flowability, the nano silica ash does not activate the pozzolanic activity to delay the early hydration reaction, and the C-S-H gel dense structure is not formed, the strength improvement is limited, the water permeation channel is not filled, and the complexing agent does not solidify the heavy metals, resulting in excessive leaching. Before adding the modifier, the filling slurry has a 28d strength of 1.02Mpa, which is lower than 1.5Mpa, and the flowability is low, which is difficult to apply in the mine filling. After using the fly ash modifier, the flowability, strength at different ages and impermeability of the mine filling sand mortar are obviously improved, indicating that the application of fly ash modifier in mine filling can improve the filling efficiency and reduce the water seepage of mine filling.

[0097] The mine filling solidifying materials obtained in example 4 and comparative example 2 are respectively subjected to flowability test, compressive strength test and impermeability test, and the test results are shown in Table 2:

[0098] Table II: Index test table of mine filling mortar before and after adding fine tailings

[0099]

[0100] From Table II, it can be concluded that the viscosity of the slurry in Comparative Example 2 increases due to the lack of fine tailings, the gap between coarse sand is not filled with fine sand, and the pore connectivity is high, and the impermeability decreases;

[0101] The mine filling solidified materials obtained in Example 4 and Comparative Example 3 were respectively subjected to dioxin residual amount test, fluidity test, compressive strength test, and Pb leaching concentration test, and the test results are shown in Table III:

[0102] Table III: Index test table of mine filling mortar before and after fly ash treatment

[0103]

[0104] From Table III, it can be concluded that the toxicity residue in Comparative Example 2 is caused by the untreated fly ash, the chloride ion in the untreated fly ash inhibits the hydration reaction, which makes the compressive strength increase, the untreated fly ash particles agglomerate, which leads to the decrease of fluidity, and the heavy metals in the untreated fly ash are not stabilized.

[0105] The fluidity test refers to GB / T 2419-2005, "Method for Determining the Fluidity of Cement Mortar", and the mixed slurry is filled into a truncated cone test mold, the upper diameter of which is 70 mm, the lower diameter is 100 mm, the height is 60 mm, the test mold is vertically lifted to make the slurry freely flow and spread, the diameter after spreading is measured, and the vertical average value is taken, which is mm;

[0106] The compressive strength test refers to GB / T 17671-1999, "Method for Testing the Strength of Cement Mortar", the slurry is injected into a 40mm×40mm×160mm triple test mold and vibrated to compact, the strength at 3d, 7d and 28d is tested at a temperature of 20±1℃ and a humidity of ≥95%, a press machine is used to load at a rate of 2400±200N / s, and the failure load is recorded to calculate the compressive strength;

[0107] The impermeability test refers to GB / T 23440-2009, "Inorganic Waterproof and Leak-Stop Material", a cylindrical test piece with a diameter of 80mm and a height of 30mm is prepared, and the test piece is cured for 28d, then the test piece is loaded into an impermeability instrument, the water pressure starts from 0.1MPa and increases by 0.1MPa every 1 hour, and the pressure value when the test piece permeates water is recorded as the impermeability strength;

[0108] In the Pb leaching concentration test, according to HJ / T 299-2007 Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid Nitric Acid Method, the test block is crushed to a particle size of <9.5 mm, the leaching agent pH = 3.20 ± 0.05 is added at a liquid-solid ratio of 10:1, and after 18 hours of oscillation, filtration is performed, and the Pb concentration is determined by inductively coupled plasma mass spectrometry;

[0109] In the dioxin residue detection test, 1g of test block powder is Soxhlet extracted, purified by a multi-layer silica gel column, and then analyzed by high-resolution gas chromatography (HRGC) combined with high-resolution mass spectrometry (HRMS);

[0110] As can be seen from Tables 1 to 3, Comparative Example 1 shows that the modifier improves the strength by 190% and the impermeability by 167% through nano-silica activity activation and float bead grading optimization, and effectively solidifies heavy metals. Before adding the modifier, the filling slurry 28 has a strength of 1.02 MPa, which is lower than 1.5 MPa, and a low flow performance of 130 mm. Such low flowability makes the slurry difficult to transport and fill in the mine, and cannot achieve uniform and efficient filling effect, greatly limiting its practical application in filling mines.

[0111] After the mine filling slurry is applied with the filling solidifying agent and the modifier, the flowability of the slurry is greatly improved, which can flow and diffuse more smoothly in the mine roadway, ensuring that every space that needs to be filled can be uniformly covered, effectively improving the speed and quality of the filling operation. Comparative Example 2 proves that the combination of coarse particle size tailings and fine particle size tailings is the key to dense packing. Single particle size tailings lead to increased porosity and decreased strength. Comparative Example 3 shows that although the non-toxic fly ash can partially replace the cementitious material, the dioxin residue exceeds the standard by 8 times, and the heavy metal leaching concentration exceeds the national standard limit by 4 times, which has significant environmental risks.

[0112] In summary, by adding the fly ash modifier to the filling solidifying agent prepared from the harmless fly ash, the fly ash modifier forms more hydrated calcium silicate in the hydration process of the filling solidifying agent under the complexing and solubilizing effects, promotes the hydration reaction of the mine powder and the harmless fly ash, and solidifies the difficult-to-treat chloride ions in the fly ash. The active silicon ions and aluminum ions provided by the nano-silica and the float beads can form a gel in the capillary pores of the filling slurry, reduce the capillary pores, prevent the long-term immersion of the mine groundwater into the hardened slurry, and enhance the practicability of the solidifying material.

[0113] The branched chain formed by methyl alkylene butyl hydroxyethyl polyoxyethylene ether improves the flow performance of the filling slurry, the branched chain of hydroxybutyl acrylate inhibits the cracking of the hardened slurry, and the high molecular structure formed by polymerization causes the silicon-oxygen bond and aluminum-oxygen bond in the cementing material to break, release free-moving Si and Al ion monomers, form new silicon-aluminum-oxygen bonds or silicon-aluminum-chlorine, solidify harmful ions in the mine, avoid the leaching of harmful ions, and enhance the functionality of the solidified material. The use of a defoaming agent further reduces capillary voids to improve the compactness and strength of the filling slurry, and the use of a penetrating agent can reduce the internal stress of capillary tubes in the filling material slurry, form more gels inside capillary pores, and avoid the cracking of the hardened slurry.

[0114] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A mine filling solidification material prepared using municipal solid waste incineration fly ash, characterized by, The raw materials include the following mass fractions: 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, and 0.3-0.6 parts of fly ash modifier, wherein the filling curing agent is composed of harmless fly ash, S95 mineral powder, building gypsum powder, and quicklime; The fly ash modifier is prepared by the following steps: Step 1: Add deionized water to a stirring reaction kettle, then add N-hydroxymethyl acrylamide, methyl alkylene butyl hydroxyethyl polyoxyethylene ether, methyl alkylene allyl alcohol, ammonium persulfate, and ferrous sulfate solution in sequence, stir at room temperature for 30 minutes, and obtain premix A; Step 2: Heat premix A to 60°C, and uniformly drop mixed preparation, wherein the raw materials of the mixed preparation are acrylic acid and hydroxybutyl acrylate, add stannous chloride when dropping the mixed preparation for 30 minutes, and continue to drop the remaining mixed preparation, obtain premix B; Step 3: After the preparation of premix B is completed, maintain 60°C reaction for 30 minutes, then add pentanediol, and continue to react for 60 minutes, then transfer to a spray dryer, set the inlet temperature to 180°C and the outlet temperature to 80°C, dry to obtain a concrete stabilizer, add the concrete stabilizer, complexing agent, defoaming agent, and penetrating agent to a high-speed mixer, mix to obtain an activator; Step 4: Add nano-silica ash, floating beads, and the activator to a three-dimensional mixer, mix to obtain a fly ash modifier, improve the strength and impermeability, and effectively solidify heavy metals; The mass ratio of nano-silica fume, floating bead and activator used in step 4 is 1:1:2, the mixing time is 30 minutes, the rotation speed is set to 500 rpm, the silica content of nano-silica fume is >90%, the specific surface area of nano-silica fume is >200m 2 / g, the silica content of floating bead is >60%, the alumina content of floating bead is >30%, the density of floating bead is <0.7cm 2 / g; The preparation method of the mine filling curing material includes the following preparation steps: S1: Screen the collected household garbage incineration fly ash through a vibrating screen, place the household garbage incineration fly ash screened by the vibrating screen in a desorption device, heat to 350-400°C, and maintain for 60 minutes to remove dioxins, and obtain harmless fly ash; S2: Premix the building gypsum powder and quicklime for 5 minutes, then mix the harmless fly ash and S95 mineral powder for 20 minutes to obtain a filling curing agent; S3: Take the following raw materials according to the mass fraction: 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, and 0.3-0.6 parts of fly ash modifier; S4: Add the coarse tailings, fine tailings, filling curing agent, and fly ash modifier to a forced mixer in sequence, dry mix for 3 minutes, then slowly add deionized water, and continuously stir to obtain a mine filling curing material.

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

3. The mine filling solidified material prepared by using household waste incineration fly ash according to claim 1, characterized in that, The mass ratio of deionized water, N-hydroxymethyl acrylamide, methyl alkylene butyl hydroxyethyl polyoxyethylene ether, methyl alkylene allyl 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.

4. The mine filling solidified material prepared by using household waste incineration fly ash according to claim 1, characterized in that, The concentration of ferrous sulfate used in step 1 is 0.1%, and the stirring speed at room temperature is 300 rpm.

5. The mine filling solidified material prepared by using household waste incineration fly ash according to claim 1, characterized in that, The mass ratio of the concrete stabilizer, complexing agent, defoaming agent, and penetrating agent in step 3 is 5.5:1.5:1.5:2, wherein the complexing agent is one or both of diethylene triamine pentaacetic acid and sodium nitrilotriacetate, the defoaming agent is one or both of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylamine ether, or polyoxypropylene polyoxyethylene glycerol ether, and the penetrating agent is one or both of isooctyl triethoxysilane, sodium secondary alkyl sulfate, or sodium a-alkenyl sulfonate.

6. The mine filling solidified material prepared by using household waste incineration fly ash according to claim 1, characterized in that, The mass ratio of the fly ash, S95 mineral powder, building gypsum powder, and quicklime in S2 is 9:9:1:1, and the stirring speed is 35 rpm.

7. The mine filling solidified material prepared by using household waste incineration fly ash according to claim 1, characterized in that, The mesh size of the vibrating screen in S1 is 2-5 mm, and the duration of continuous stirring in S4 is 8-10 minutes, and the stirring speed is 200 rpm.

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