Coal mine filling paste material based on anti-sulfur curing agent and preparation method thereof

Abstract

The present application relates to the technical field of paste material, and particularly relates to a coal mine filling paste material based on anti-sulfur curing agent and a preparation method thereof, which is prepared by using industrial waste residues such as steel slag, red mud, mineral powder, carbide slag and desulfurization gypsum to partially replace cement as a curing agent, using crushed and screened coal gangue as aggregate, using composite coconut shell fiber as a modifier, introducing phosphorus-containing polycarboxylic water reducing agent and non-alkali quick-acting accelerator; the coconut shell fiber is mercapto-functionalized by using 3-mercaptopropyl trimethoxysilane, then a double-bond branched phosphoramide is grafted on the surface of the coconut shell fiber by using a thiol-double bond photoreaction; the double-bond branched phosphoramide is used as a phosphorus-containing group provider, and a phosphorus-containing polycarboxylic water reducing agent is prepared by free radical copolymerization, so that the filling paste material is significantly improved in anti-sulfate performance under the premise of maintaining good workability and mechanical properties, thereby greatly improving the durability of the filling paste material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paste material, and particularly relates to a coal mine filling paste material based on a sulfur-resistant curing agent and a preparation method thereof. BACKGROUND

[0002] The development of filling coal mining technology is beneficial to the protection of the ecological environment, and the coal mine filling paste material refers to the filling material transported to the coal mine goaf during the mining process in order to control the surface subsidence, protect the mining area environment and improve the resource utilization rate, which is usually made of coal gangue, waste rock and the like as aggregate, cement, blast furnace slag, fly ash and the like, and water.

[0003] The coal mine filling paste material is the core of the filling mining technology and is closely related to the quality of the filling body and the economic benefits of mining, and the accumulation of high-concentration sulfate ions in the mine water has a significant impact on the normal hydration reaction of cement, blast furnace slag and the like in the general paste material, and the filling body after condensation and hardening will also be seriously eroded and damaged under the action of the sulfate, thereby causing the instability and cracking of the filling body. SUMMARY

[0004] The present application aims to provide a coal mine filling paste material based on a sulfur-resistant curing agent and a preparation method thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme:

[0006] A preparation method of a coal mine filling paste material based on a sulfur-resistant curing agent, comprising the following steps:

[0007] S1: mixing coal gangue, industrial waste slag, cement and activator to obtain a mixture A;

[0008] S2: mixing a phosphorus-containing polycarboxylate superplasticizer, composite coconut shell fiber, accelerator and water to obtain a mixture B;

[0009] S3: mixing the mixture A and the mixture B to obtain a coal mine filling paste material based on a sulfur-resistant curing agent.

[0010] Further, the industrial waste slag mixture is obtained by compounding steel slag, red mud, mineral powder, calcium carbide slag and desulfurization gypsum at a mass ratio of 3:3:2:1:1, the particle size of the steel slag and the red mud is 2-4 mu, and the particle size of the mineral powder, the calcium carbide slag and the desulfurization gypsum is 1-2 mu.

[0011] Further, the water is one of deionized water, ultrapure water and tap water.

[0012] Further, the accelerator is aluminum sulfate octadecahydrate, diethanolamine, 4-methylphenol, water, and lysine, compounded in a mass ratio of 58:6:0.1:35:0.1.

[0013] Further, the activator is one or several of sodium silicate, sodium carbonate, and sodium hydroxide.

[0014] Further, the raw material composition of the filling paste material is, in parts by weight: coal gangue 53-73 parts, industrial waste residue mixture 24-32 parts, cement 5-10 parts, activator 1-3 parts, phosphorus-containing polycarboxylic acid water reducer 1-2 parts, composite coconut shell fiber 3-6 parts, accelerator 0.5-1 part, and water 58-68 parts.

[0015] Further, the preparation of the composite coconut shell fiber comprises the following steps:

[0016] 1) Mix the coconut shell fiber and sodium hydroxide solution, stir for 1-2 hours, wash and dry to obtain pretreated coconut shell fiber;

[0017] 2) Under a nitrogen atmosphere, mix anhydrous ethanol, deionized water, 3-mercaptopropyl trimethoxysilane, and ammonia water, heat to 60-70°C in a water bath for 2-3 hours, stir for 20-30 minutes, add the pretreated coconut shell fiber, stir at 18-25°C for 5-6 hours, wash with ethanol and deionized water 3-5 times in sequence, and dry to obtain mercapto-modified coconut shell fiber;

[0018] 3) Mix the mercapto-modified coconut shell fiber, N,N-dimethylformamide, and photoinitiator, add the branched phosphoramide containing double bonds and N,N-dimethylformamide mixture, heat to 50-60°C, and treat with ultraviolet light, wash, and dry to obtain the composite coconut shell fiber.

[0019] Further, the working conditions for ultraviolet light treatment are: irradiation under 278 nm ultraviolet light for 5-6 hours.

[0020] Further, the preparation of the phosphorus-containing polycarboxylic acid water reducer comprises the following steps:

[0021] Under a nitrogen atmosphere, mix methyl allyl polyoxyethylene ether and deionized water, heat to 58-62°C, add ammonium persulfate, add the mixture of acrylic acid, branched phosphoramide containing double bonds, and deionized water, stir for 2-3 hours, add the mixture of ascorbic acid, 3-mercaptopropionic acid, and deionized water, stir for 3-4 hours, cool, and adjust the pH to neutral to obtain the phosphorus-containing polycarboxylic acid water reducer.

[0022] Further, the mass ratio of methyl allyl polyoxyethylene ether, acrylic acid, and branched phosphoramide containing double bonds is 24:2.9:3.2.

[0023] Further, the preparation of the branched phosphoramide containing double bonds comprises the following steps:

[0024] (1) under the nitrogen atmosphere, diethanolamine, dioxane are mixed, a mixed solution of phosphorus oxychloride, dioxane is added at 0-5 DEG C, and is warmed to 38-42 DEG C for 22-24h, a mixed solution of triethylamine, dioxane is added, and is warmed to 78-82 DEG C for 22-24h, is distilled under reduced pressure, deionized water is added, sodium hydroxide is added, stirring, suction filtration, distillation under reduced pressure, methanol is added, suction filtration, distillation under reduced pressure, drying, to obtain a multi-hydroxyl branched phosphoramide;

[0025] (2) under the nitrogen atmosphere, multi-hydroxyl branched phosphoramide, N,N-dimethylformamide is mixed, anhydrous potassium carbonate is added, a mixed solution of acryloyl chloride, N,N-dimethylformamide is added in an ice bath, ice bath stirring 1-2h, is preserved in the dark for 22-23h, suction filtration, rotary evaporation, to obtain a double bond branched phosphoramide.

[0026] Compared with the prior art, the beneficial effects of the present application are:

[0027] The present application provides a kind of coal mine filling paste material based on anti-sulfur curing agent and preparation method thereof, utilize steel slag, red mud, mineral powder, calcium carbide slag, desulfurization gypsum etc.Industrial waste residue partially replaces cement as curing agent, to crush screened coal gangue as aggregate, with composite coconut shell fiber as modifier, introduce phosphorus-containing polycarboxylic acid water reducing agent and non-alkali accelerator, to prepare the coal mine filling paste material with high strength, strong resistance to sulfate, high stability, realize waste to treasure.

[0028] Common coal mine filling paste material is easy to cause internal crack propagation and pore increase under the erosion of sulfate solution, in the present application, steel slag, red mud, mineral powder, calcium carbide slag, desulfurization gypsum etc.Industrial waste residue is selected, by controlling the ratio and particle size, the advantages of volcanic ash effect, micro aggregate filling effect, alkali activation effect etc.In the composition, complementary, make it increase the compactness of paste material, slow down the speed of sulfate solution invasion, play the role of sulfate resistant curing agent, improve the durability of paste material.

[0029] In the filling paste material, introduce easily accessible, green and environmentally friendly, excellent mechanical properties coconut shell fiber as modifier to improve the mechanical strength of filling paste material, to improve the uniformity of coconut shell fiber dispersion in filling paste material, first use 3-mercapto propyl trimethoxysilane to mercapto group coconut shell fiber, then use the thiol-double bond photoreaction, grafting double bond branched phosphoramide on its surface, improve the bonding strength of coconut shell fiber and filling paste material, wherein double bond branched phosphoramide is first synthesized with phosphorus oxychloride and diethanolamine as raw material, then prepared by introducing carbon-carbon double bond through acryloyl chloride, wherein the introduction of multiple phosphorus groups can greatly improve the sulfate resistance of filling paste material, further improve the durability and stability of filling paste material.

[0030] In order to adjust the viscosity of the filling paste material and further improve the sulfate resistance of the filling paste material, the branched phosphamide containing double bonds is used as a phosphorus-containing group to provide a body, a phosphorus-containing polycarboxylic acid water reducer is prepared by free radical copolymerization, the sulfate resistance of the filling paste material is significantly improved under the premise of maintaining good workability and mechanical properties, and the durability of the filling paste material is greatly improved. DETAILED DESCRIPTION

[0031] The technical solutions in the present application will be described clearly and completely below in combination with 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. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0032] It should be noted that if the embodiments of the present application involve directional indications such as up, down, left, right, front, back, the directional indications are only used to explain the relative position relationship, movement condition and the like between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that the technical solutions can be realized by those skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0033] The technical solutions of the present application will be described in further detail below in combination with specific embodiments. It should be understood that the following embodiments are only used to explain the present application, and are not used to limit the present application.

[0034] Embodiment 1: A preparation method of a coal mine filling paste material based on a sulfate-resistant curing agent, comprising the following steps:

[0035] S1: mixing coal gangue, industrial waste residue, cement, and an activator to obtain a mixture A;

[0036] S2: mixing a phosphorus-containing polycarboxylic acid water reducer, a composite coconut fiber, a quick-setting agent, and deionized water to obtain a mixture B;

[0037] The industrial waste residue mixture is obtained by compounding steel slag, red mud, mineral powder, calcium carbide slag, and desulfurization gypsum at a mass ratio of 3:3:2:1:1, the particle size of the steel slag and the red mud is 2 μm, and the particle size of the mineral powder, the calcium carbide slag, and the desulfurization gypsum is 1 μm;

[0038] The accelerator is sodium silicate, and the setting accelerator is aluminum sulfate octadecahydrate, diethanolamine, 4-methylphenol, deionized water, and lysine, which are compounded in a mass ratio of 58:6:0.1:35:0.1;

[0039] The raw material composition of the filling paste material is 53 parts of coal gangue, 24 parts of industrial waste residue mixture, 5 parts of cement, 1 part of the accelerator, 1 part of the phosphorus-containing polycarboxylic acid water reducer, 3 parts of the composite coconut shell fiber, 0.5 parts of the setting accelerator, and 58 parts of deionized water, by weight;

[0040] The preparation of the composite coconut shell fiber comprises the following steps:

[0041] 1) 10 g of coconut shell fiber is mixed with 400 mL of a 15% by mass sodium hydroxide solution, stirred for 1 h, washed, and dried to obtain pretreated coconut shell fiber;

[0042] 2) 60 mL of anhydrous ethanol, 10.5 mL of deionized water, 0.42 g of 3-mercaptopropyltrimethoxysilane, and 0.6 mL of ammonia water are mixed under a nitrogen atmosphere, heated to 60°C in a water bath for 3 h, stirred for 20 min, 1 g of pretreated coconut shell fiber is added, stirred at 18°C for 6 h, washed with ethanol and deionized water for 3-5 times, and dried to obtain mercapto-modified coconut shell fiber;

[0043] 3) 3.2 g of mercapto-modified coconut shell fiber, 60 mL of N,N-dimethylformamide, and 46 mg of photoinitiator 1173 are mixed, 1.4 g of branched phosphoramide containing double bonds is added, 25 mL of N,N-dimethylformamide is added, heated to 50°C, and irradiated with ultraviolet light at 278 nm for 5 h, washed, and dried to obtain the composite coconut shell fiber;

[0044] The preparation of the phosphorus-containing polycarboxylic acid water reducer comprises the following steps:

[0045] 24 g of methyl allyl polyoxyethylene ether and 200 mL of deionized water are mixed under a nitrogen atmosphere, heated to 58°C, 480 mg of ammonium persulfate is added, a mixture of 2.9 g of acrylic acid, 3.2 g of branched phosphoramide containing double bonds, and 50 mL of deionized water is added, stirred for 2 h, a mixture of 160 mg of ascorbic acid, 160 mg of 3-mercaptopropionic acid, and 10 mL of deionized water is added, stirred for 3 h, cooled, and the pH is adjusted to neutral to obtain the phosphorus-containing polycarboxylic acid water reducer;

[0046] The preparation of the branched phosphoramide containing double bonds comprises the following steps:

[0047] (1) Under the atmosphere of nitrogen, 21 g of diethanolamine, 100 mL of dioxane were mixed, and a mixture of 15.4 g of phosphorus oxychloride, 25 mL of dioxane was added at 0°C, and the temperature was raised to 38°C for 24 h, and a mixture of 20 g of triethylamine, 25 mL of dioxane was added, and the temperature was raised to 78°C for 24 h, and distilled under reduced pressure, and 10 mL of deionized water was added, and 8 g of sodium hydroxide was added, and stirred, filtered, distilled under reduced pressure, and 25 mL of methanol was added, and filtered, distilled under reduced pressure, and dried to obtain a polyhydroxy branched phosphoramide;

[0048] (2) Under the atmosphere of nitrogen, 2.4 g of polyhydroxy branched phosphoramide, 80 mL of N,N-dimethylformamide were mixed, and 0.3 g of anhydrous potassium carbonate was added, and a mixture of 0.3 g of acryloyl chloride, 20 mL of N,N-dimethylformamide was added in an ice bath, and stirred for 1 h, and incubated in the dark for 22 h, and filtered, and rotary evaporated to obtain a double bond branched phosphoramide;

[0049] S3: mixing the mixture A and the mixture B to obtain a coal mine filling paste material based on the sulfur-resistant curing agent.

[0050] Example 2: A preparation method of a coal mine filling paste material based on a sulfur-resistant curing agent, comprising the following steps:

[0051] S1: mixing coal gangue, industrial waste residue, cement, and activator to obtain mixture A;

[0052] S2: mixing phosphorus-containing polycarboxylic acid water reducer, composite coconut shell fiber, accelerator, and deionized water to obtain mixture B;

[0053] The industrial waste residue mixture is obtained by compounding steel slag, red mud, mineral powder, calcium carbide slag, and desulfurization gypsum in a mass ratio of 3:3:2:1:1, and the particle size of the steel slag and the red mud is 2 μm, and the particle size of the mineral powder, the calcium carbide slag, and the desulfurization gypsum is 1 μm;

[0054] The accelerator is obtained by compounding aluminum sulfate octadecahydrate, diethanolamine, 4-methylphenol, deionized water, and lysine in a mass ratio of 58:6:0.1:35:0.1; and the activator is sodium silicate;

[0055] In terms of weight fraction, the raw material composition of the filling paste material is: coal gangue 63 parts, industrial waste residue mixture 28 parts, cement 7 parts, activator 2 parts, phosphorus-containing polycarboxylic acid water reducer 1.5 parts, composite coconut shell fiber 5 parts, accelerator 0.8 parts, and deionized water 60 parts;

[0056] The preparation of the composite coconut shell fiber comprises the following steps:

[0057] 1) 10 g of coconut shell fiber was mixed with 400 mL of 15% sodium hydroxide solution, stirred for 1.5 h, washed and dried to obtain pretreated coconut shell fiber;

[0058] 2) Under the atmosphere of nitrogen, 60 mL of anhydrous ethanol, 10.5 mL of deionized water, 0.42 g of 3-mercaptopropyl trimethoxysilane, and 0.6 mL of ammonia water were mixed, and heated to 65°C water bath for 2.5 h, stirred for 25 min, 1 g of pretreated coconut shell fiber was added, stirred at 20°C for 5.5 h, washed with ethanol and deionized water for 4 times, and dried to obtain mercapto coconut shell fiber;

[0059] 3) 3.2 g of mercapto coconut shell fiber, 60 mL of N,N-dimethylformamide, and 46 mg of photoinitiator 1173 were mixed, 1.4 g of branched phosphonamide containing double bond was added, and 25 mL of N,N-dimethylformamide was mixed, heated to 55°C, and irradiated with ultraviolet light at 278 nm for 5-6 h, washed and dried to obtain composite coconut shell fiber;

[0060] The preparation of the phosphorus-containing polycarboxylic acid water reducer comprises the following steps:

[0061] Under the atmosphere of nitrogen, 24 g of methyl allyl polyoxyethylene ether and 200 mL of deionized water were mixed, heated to 60°C, 480 mg of ammonium persulfate was added, a mixture of 2.9 g of acrylic acid, 3.2 g of branched phosphonamide containing double bond, and 50 mL of deionized water was added, stirred for 2.5 h, a mixture of 160 mg of ascorbic acid, 160 mg of 3-mercaptopropionic acid, and 10 mL of deionized water was added, stirred for 3.5 h, cooled, and the pH was adjusted to neutral to obtain a phosphorus-containing polycarboxylic acid water reducer;

[0062] The preparation of the branched phosphonamide containing double bond comprises the following steps:

[0063] (1) Under the atmosphere of nitrogen, 21 g of diethanolamine and 100 mL of dioxane were mixed, a mixture of 15.4 g of phosphorus oxychloride and 25 mL of dioxane was added at 3°C, heated to 40°C for 23 h, a mixture of 20 g of triethylamine and 25 mL of dioxane was added, heated to 80°C for 23 h, distilled under reduced pressure, 10 mL of deionized water was added, 8 g of sodium hydroxide was added, stirred, suction filtered, distilled under reduced pressure, 25 mL of methanol was added, suction filtered, distilled under reduced pressure, and dried to obtain a polyhydroxy branched phosphonamide;

[0064] (2) Under the atmosphere of nitrogen, 2.4 g of the polyhydroxy branched phosphonamide and 80 mL of N,N-dimethylformamide were mixed, 0.3 g of anhydrous potassium carbonate was added, a mixture of 0.3 g of acryloyl chloride and 20 mL of N,N-dimethylformamide was added in an ice bath, stirred in the ice bath for 1.5 h, and incubated in the dark for 22.5 h, suction filtered, and rotary evaporated to obtain a branched phosphonamide containing double bond;

[0065] S3: The mixture A and the mixture B were mixed to obtain a coal mine filling paste material based on the anti-sulfur curing agent.

[0066] Embodiment 3: A preparation method of a coal mine filling paste material based on an anti-sulfur curing agent, comprising the following steps:

[0067] S1: mixing coal gangue, industrial waste residue mixture, cement, activator to obtain a mixture A;

[0068] S2: mixing phosphorus-containing polycarboxylate superplasticizer, composite coconut shell fiber, accelerator, deionized water to obtain a mixture B;

[0069] The industrial waste residue mixture is compounded by steel slag, red mud, mineral powder, calcium carbide slag and desulfurization gypsum in a mass ratio of 3:3:2:1:1, and the particle size of the steel slag and the red mud is 2 μm, and the particle size of the mineral powder, the calcium carbide slag and the desulfurization gypsum is 1 μm;

[0070] The accelerator is compounded by aluminum sulfate octadecahydrate, diethanolamine, 4-methylphenol, deionized water and lysine in a mass ratio of 58:6:0.1:35:0.1, and the activator is sodium silicate;

[0071] The raw material composition of the filling paste material is: coal gangue 73 parts, industrial waste residue mixture 32 parts, cement 10 parts, activator 3 parts, phosphorus-containing polycarboxylate superplasticizer 2 parts, composite coconut shell fiber 6 parts, accelerator 1 part, and deionized water 68 parts, by weight;

[0072] The preparation of the composite coconut shell fiber comprises the following steps:

[0073] 1) 10 g of coconut shell fiber is mixed with 400 mL of a 15% mass fraction sodium hydroxide solution, stirred for 1-2 h, washed and dried to obtain pretreated coconut shell fiber;

[0074] 2) Under a nitrogen atmosphere, 60 mL of anhydrous ethanol, 10.5 mL of deionized water, 0.42 g of 3-mercaptopropyltrimethoxysilane and 0.6 mL of ammonia water are mixed, heated to 70°C in a water bath for 2 h, stirred for 30 min, 1 g of pretreated coconut shell fiber is added, stirred at 25°C for 5 h, washed with ethanol and deionized water for 3-5 times, and dried to obtain mercapto coconut shell fiber;

[0075] 3) 3.2 g of mercapto coconut shell fiber, 60 mL of N,N-dimethylformamide and 46 mg of photoinitiator 1173 are mixed, 1.4 g of double-bond-containing branched phosphoramide and 25 mL of N,N-dimethylformamide are added, heated to 60°C, and irradiated with ultraviolet light at 278 nm for 5 h, washed and dried to obtain composite coconut shell fiber;

[0076] The preparation of the phosphorus-containing polycarboxylate superplasticizer comprises the following steps:

[0077] Mixing 24 g of methyl allyl polyoxyethylene ether, 200 mL of deionized water under a nitrogen atmosphere, heating to 62℃, adding 480 mg of ammonium persulfate, adding a mixture of 2.9 g of acrylic acid, 3.2 g of double bond containing branched phosphoramide, 50 mL of deionized water, stirring for 3 h, adding a mixture of 160 mg of ascorbic acid, 160 mg of 3-mercaptopropionic acid, 10 mL of deionized water, stirring for 4 h, cooling, and adjusting the pH to neutral to obtain a phosphorus-containing polycarboxylic acid water reducer;

[0078] The preparation of the double bond containing branched phosphoramide comprises the following steps:

[0079] (1) Mixing 21 g of diethanolamine, 100 mL of dioxane under a nitrogen atmosphere, adding a mixture of 15.4 g of phosphorus oxychloride, 25 mL of dioxane at 5℃, heating to 42℃ for 22 h, adding a mixture of 20 g of triethylamine, 25 mL of dioxane, heating to 82℃ for 22 h, distilling under reduced pressure, adding 10 mL of deionized water, adding 8 g of sodium hydroxide, stirring, suction filtering, distilling under reduced pressure, adding 25 mL of methanol, suction filtering, distilling under reduced pressure, and drying to obtain a polyhydroxy branched phosphoramide;

[0080] (2) Mixing 2.4 g of the polyhydroxy branched phosphoramide, 80 mL of N,N-dimethylformamide under a nitrogen atmosphere, adding 0.3 g of anhydrous potassium carbonate, adding a mixture of 0.3 g of acryloyl chloride, 20 mL of N,N-dimethylformamide in an ice bath, stirring in an ice bath for 2 h, incubating in the dark for 23 h, suction filtering, and rotary evaporating to obtain a double bond containing branched phosphoramide;

[0081] S3: Mixing the mixture A and the mixture B to obtain a coal mine filling paste material based on the anti-sulfur curing agent.

[0082] Comparative Example 1: Taking Example 3 as a control group, using coconut fiber to replace the composite coconut fiber, and other procedures being normal.

[0083] Comparative Example 2: Taking Example 3 as a control group, without preparing a double bond containing branched phosphoramide, and other procedures being normal.

[0084] The sources of the raw materials used (only as an exemplary example) are as follows:

[0085] The main chemical composition of the coal gangue (particle size of 20 μm) is as follows: 60.2% of silicon dioxide, 2.6% of calcium oxide, 18.3% of aluminum oxide, 4.6% of iron oxide, 1.5% of magnesium oxide, 0.6% of potassium oxide, 0.2% of sulfur trioxide, and 0.7% of sodium oxide, which are commercially available;

[0086] The main chemical composition of red mud: 11.5% of silicon dioxide, 20.2% of calcium oxide, 32.2% of aluminum oxide, 6.9% of iron oxide, 1.1% of magnesium oxide, 0.5% of potassium oxide, 3.3% of titanium oxide, 3.8% of sodium oxide, commercially available;

[0087] The main chemical composition of steel slag: 17.9% of silicon dioxide, 19.7% of calcium oxide, 8.8% of aluminum oxide, 23.1% of iron oxide, 13.9% of magnesium oxide, 0.2% of potassium oxide, 0.6% of sulfur trioxide, 0.7% of phosphorus pentoxide, commercially available;

[0088] The main chemical composition of mineral powder: 31.1% of silicon dioxide, 36.8% of calcium oxide, 13.6% of aluminum oxide, 4.2% of iron oxide, 7.0% of magnesium oxide, 0.2% of potassium oxide, 0.1% of sodium oxide, 0.5% of sulfur trioxide, 0.7% of titanium oxide, commercially available;

[0089] The main chemical composition of carbide slag: 65.8% of calcium oxide, 3.2% of silicon oxide, 1% of aluminum oxide, 0.2% of sodium oxide, commercially available;

[0090] The main chemical composition of desulfurization gypsum: 4.1% of silicon dioxide, 33.8% of calcium oxide, 0.7% of aluminum oxide, 0.6% of iron oxide, 0.9% of magnesium oxide, 0.1% of potassium oxide, 0.4% of sodium oxide, 45.1% of sulfur trioxide, commercially available;

[0091] Coconut shell fiber (2 μm, Hainan), commercially available; cement (PO42.5 ordinary Portland cement): Hailuo cement; aluminum sulfate octadecahydrate A489714, diethanolamine D112360, 4-methylphenol C108249, lysine L163872, 3-mercaptopropyltrimethoxysilane M100619, photoinitiator 1173 H110280, methylallyl polyoxyethylene ether A303301, acrylic acid A103526, diethanolamine D112360, phosphorus oxychloride P475214, acryloyl chloride A104614: aladdin reagent; sodium hydroxide, ethanol, ammonia, dioxane, ammonium persulfate, ascorbic acid, 3-mercaptopropionic acid, methanol, N,N-dimethylformamide, potassium carbonate, sodium silicate, analytically pure, commercially available.

[0092] Performance test:

[0093] The samples prepared in the examples and comparative examples were tested;

[0094] Compressive strength: the size of the test piece was 40 mm × 40 mm × 40 mm, and the compressive strength was tested by an electronic universal testing machine after 28 d curing;

[0095] Durability: 3% anhydrous sodium sulfate aqueous solution is configured, a 40mm cube is immersed therein, and the compressive strength is tested again after being incubated at 25℃ for 7d, and compared with the compressive strength without being immersed in the sodium sulfate aqueous solution, and the compressive strength change rate is 0-1% (including 1%) for excellent, otherwise for unqualified; the obtained results are shown in Table 1;

[0096] Table 1

[0097]

[0098] The application provides a coal mine filling paste material based on a sulfur-resistant curing agent and a preparation method thereof, industrial waste residues such as steel slag, red mud, mineral powder, calcium carbide slag and desulfurization gypsum are used to partially replace cement as a curing agent, crushed and screened coal gangue is used as an aggregate, and a composite coconut shell fiber is used as a modifier, a phosphorus-containing polycarboxylic acid water reducing agent and an alkali-free accelerator are introduced, a coal mine filling paste material with high strength, strong resistance to sulfates and high stability is prepared, and waste is turned into treasure.

[0099] Comparing Example 3 with Comparative Example 1 shows that the coconut shell fiber which is easy to obtain, green and environmentally friendly and has excellent mechanical properties is introduced into the filling paste material as a modifier to improve the mechanical strength of the filling paste material, in order to improve the uniformity of the dispersion of the coconut shell fiber in the filling paste material, the coconut shell fiber is mercaptanized by using 3-mercaptopropyl trimethoxysilane, then a double-bond-containing branched phosphoramide is grafted on the surface of the coconut shell fiber through a thiol-double bond photoreaction, and the bonding strength of the coconut shell fiber and the filling paste material is improved, wherein the double-bond-containing branched phosphoramide is prepared by first synthesizing a polyhydroxy branched phosphoramide from phosphorus oxychloride and diethanolamine, and then introducing a carbon-carbon double bond through acryloyl chloride, and the introduction of the polyphosphorus group can greatly improve the sulfate resistance of the filling paste material and further improve the durability and stability of the filling paste material.

[0100] Comparing Example 3 with Comparative Example 2 shows that, in order to adjust the viscosity of the filling paste material and further improve the sulfate resistance of the filling paste material, the double-bond-containing branched phosphoramide is used as a phosphorus-containing group provider in the application, a phosphorus-containing polycarboxylic acid water reducing agent is prepared through free radical copolymerization, the clay resistance and sulfate resistance of the filling paste material are significantly improved on the premise that the filling paste material maintains good workability and mechanical properties, and thus the durability of the filling paste material is greatly improved.

[0101] The above description is only an embodiment of the application, and does not limit the patent range of the application, and any equivalent structural transformation made according to the application concept or direct / indirect application in other related technical fields is included in the patent protection range of the application.

Claims

1. A method for the preparation of a sulphur resistant binder based paste material for coal mine backfilling, characterised in that, The preparation method comprises the following steps: S1: mixing coal gangue, industrial waste residue, cement, and activator to obtain mixture A; S2: mixing phosphorus-containing polycarboxylic acid water reducer, composite coconut shell fiber, accelerator, and water to obtain mixture B; S3: mixing mixture A and mixture B to obtain a coal mine filling paste material based on the sulfur-resistant curing agent; The preparation of the composite coconut shell fiber comprises the following steps: 1) mixing coconut shell fiber and sodium hydroxide solution, stirring for 1-2 h, washing, and drying to obtain pretreated coconut shell fiber; 2) mixing anhydrous ethanol, deionized water, 3-mercaptopropyl trimethoxysilane, and ammonia water under a nitrogen atmosphere, heating to 60-70°C in a water bath for 2-3 h, stirring for 20-30 min, adding the pretreated coconut shell fiber, stirring at 18-25°C for 5-6 h, washing with ethanol and deionized water for 3-5 times, and drying to obtain mercapto-modified coconut shell fiber; 3) mixing the mercapto-modified coconut shell fiber, N,N-dimethylformamide, and photoinitiator, adding double-bond branched phosphoramide and N,N-dimethylformamide, heating to 50-60°C, and treating under ultraviolet light, and washing and drying to obtain the composite coconut shell fiber.

2. A method of preparing a paste material for coal mine backfilling based on anti-sulfur curing agent according to claim 1, characterized in that, The industrial waste residue mixture is prepared by compounding steel slag, red mud, mineral powder, calcium carbide slag, and desulfurization gypsum at a mass ratio of 3:3:2:1:1, wherein the particle size of the steel slag and the red mud is 2-4 µm, and the particle size of the mineral powder, the calcium carbide slag, and the desulfurization gypsum is 1-2 µm.

3. A method of preparing a paste material for coal mine filling based on anti-sulfur curing agent according to claim 1, characterized in that, The accelerator is prepared by compounding aluminum sulfate octadecahydrate, diethanolamine, 4-methylphenol, water, and lysine at a mass ratio of 58:6:0.1:35:0.

1.

4. A method of preparing a paste material for coal mine filling based on anti-sulfur curing agent according to claim 1, characterized in that, The activator is one or more of sodium silicate, sodium carbonate, and sodium hydroxide.

5. The preparation method of the coal mine filling paste material based on the sulfur-resistant curing agent according to claim 1, wherein the raw material composition of the filling paste material comprises, in parts by weight, coal gangue 53-73 parts, industrial waste residue mixture 24-32 parts, cement 5-10 parts, activator 1-3 parts, phosphorus-containing polycarboxylic acid water reducer 1-2 parts, composite coconut shell fiber 3-6 parts, accelerator 0.5-1 part, and water 58-68 parts.

6. A method of preparing a paste material for coal mine filling based on anti-sulfur curing agent according to claim 1, characterized in that, The preparation of the phosphorus-containing polycarboxylic acid water reducer comprises the following steps: Under a nitrogen atmosphere, methyl allyl polyoxyethylene ether and deionized water are mixed, heated to 58-62°C, ammonium persulfate is added, a mixed solution of acrylic acid, double-bond branched phosphoramide, and deionized water is added, stirred for 2-3 h, a mixed solution of ascorbic acid, 3-mercaptopropionic acid, and deionized water is added, stirred for 3-4 h, cooled, and the pH is adjusted to neutral to obtain the phosphorus-containing polycarboxylic acid water reducer.

7. A method of preparing a paste material for coal mine backfilling based on anti-sulfur curing agent according to claim 6, characterized in that, The mass ratio of methyl allyl polyoxyethylene ether, acrylic acid, and double-bond branched phosphoramide is 24:2.9:3.

2.

8. A method of preparing a paste material for coal mine filling based on anti-sulfur curing agent according to claim 1, characterized in that, The preparation of the double-bond branched phosphoramide comprises the following steps: (1) under nitrogen atmosphere, diethanolamine, dioxane were mixed, a mixed solution of phosphorus oxychloride, dioxane was added at 0-5℃, warmed to 38-42℃ for 22-24h, a mixed solution of triethylamine, dioxane was added, warmed to 78-82℃ for 22-24h, distilled under reduced pressure, deionized water was added, sodium hydroxide was added, stirred, suction filtered, distilled under reduced pressure, methanol was added, suction filtered, distilled under reduced pressure, dried to obtain a polyhydroxyl branched phosphoramide; (2) under nitrogen atmosphere, the polyhydroxyl branched phosphoramide, N,N-dimethylformamide were mixed, anhydrous potassium carbonate was added, a mixed solution of acryloyl chloride, N,N-dimethylformamide was added in an ice bath, stirred in an ice bath for 1-2h, incubated in the dark for 22-23h, suction filtered, rotary evaporated to obtain a double bond branched phosphoramide.

9. A coal mine backfill paste material based on anti-sulfur curing agents, characterized in that, Prepared according to the preparation method of any one of claims 1-8.

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