A solid waste-based mine filling composite material and its preparation method

Abstract

This invention relates to the field of mine backfill materials technology, specifically to a solid waste-based mine backfill composite material and its preparation method. The raw materials for preparing the solid waste-based mine backfill composite material include the following components in parts by weight: 3-5 parts epoxy-eugenol-HCCP, 6-9 parts SH-polyurethane-SiO2, 30-40 parts coal gangue, 20-30 parts red mud, 20-30 parts 42.5 grade ordinary silicate cement, 40-50 parts water, and 0.3-0.5 parts polycarboxylate superplasticizer. This invention utilizes an organic-inorganic interpenetrating crosslinked network constructed from epoxy-eugenol-HCCP and SH-polyurethane-SiO2 to prepare a backfill composite material with high strength and excellent freeze-thaw resistance, while simultaneously absorbing solid waste such as coal gangue and red mud.

Description

Technical Field

[0001] This invention relates to the field of mine filling materials technology, specifically to a solid waste-based mine filling composite material and its preparation method. Background Technology

[0002] Coal gangue and red mud are solid wastes with large annual emissions and accumulating volumes. Long-term stockpiling of coal gangue easily causes soil, air, and water pollution. Red mud's high pH value, high heavy metal content, and radioactive elements easily lead to soil alkalization and groundwater pollution, seriously threatening the ecological environment and human health. Underground mining leaves behind large areas of mined-out areas; if the surface collapses, it endangers the safety of workers inside the mine, severely damages the ecological environment, and causes huge economic losses. Using coal gangue and red mud to make mine backfill materials can not only consume large quantities of solid waste such as coal gangue and red mud but also ensure the geological stability of mined-out areas, solving the environmental problems caused by solid waste stockpiling. However, how to design material components to give such solid waste-based backfill materials high strength, excellent freeze-thaw resistance, and flame retardant properties remains a pressing problem to be solved. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a solid waste-based mine filling composite material and its preparation method.

[0004] This invention is achieved through the following technical solution: A solid waste-based mine filling composite material, the raw materials for which are prepared include the following components in parts by weight: 3-5 parts of epoxy eugenol-HCCP, 6-9 parts of SH-polyurethane-SiO2, 30-40 parts of coal gangue, 20-30 parts of red mud, 20-30 parts of 42.5 grade ordinary silicate cement, 40-50 parts of water, and 0.3-0.5 parts of polycarboxylate superplasticizer.

[0005] Furthermore, the coal gangue has a particle size of 40-50 μm, and the red mud has a particle size of 40-60 μm.

[0006] Furthermore, the preparation method of the epoxy eugenol-HCCP includes the following steps: L1. Under a nitrogen atmosphere, eugenol was added to dioxane and stirred until dissolved. Then tetrabutylammonium bromide was added and stirred at room temperature for 30 min. NaOH was then added and the temperature was raised to 40℃ and maintained for 3 h to obtain a reaction solution. Hexachlorocyclotriphosphazene (HCCP) was dissolved in dioxane to obtain an HCCP solution. The HCCP solution was added dropwise to the reaction solution and stirred at 70℃ for 48 h. L2. After the reaction in step L1 is completed, cool to room temperature, filter, concentrate the filtrate by rotary evaporation to remove the solvent, dissolve the product in dichloromethane, wash with deionized water and saturated NaCl aqueous solution, dry the organic phase with anhydrous sodium sulfate, filter, remove dichloromethane by rotary evaporation, wash with ethanol, dry, and obtain eugenol-HCCP. ; L3. The eugenol-HCCP obtained in step L2 was dissolved in dichloromethane to obtain an eugenol-HCCP solution. m-chloroperoxybenzoic acid was added to dichloromethane and mixed to obtain a suspension. The eugenol-HCCP solution was added dropwise to the suspension at 0-4℃. After the addition was complete, the reaction was carried out at 40℃ for 12-14 h. After the reaction was completed, the mixture was filtered. The filtrate was washed with saturated Na2S2O3 solution, saturated NaHCO3 solution, saturated NaCl solution and deionized water. The organic phase was dried with anhydrous sodium sulfate. After filtration, the mixture was rotary evaporated and dried under vacuum at 60℃ to obtain epoxy eugenol-HCCP. .

[0007] Further, in step L1, the mass ratio of eugenol, tetrabutylammonium bromide, NaOH, and hexachlorocyclotriphosphazene is 180:1:44:60.

[0008] Further, in step L1, the mass concentration of eugenol in dioxane is 0.15-0.18 g / mL.

[0009] Furthermore, in step L1, the mass concentration of the hexachlorocyclotriphosphazene in dioxane is 0.15-0.2 g / mL.

[0010] Further, in step L3, the mass concentration of eugenol-HCCP in dichloromethane is 60-100 mg / mL.

[0011] Further, in step L3, the mass ratio of eugenol-HCCP to m-chloroperoxybenzoic acid is 1:1.2-1.4.

[0012] Furthermore, in step L3, the mass concentration of the m-chloroperoxybenzoic acid in dichloromethane is 0.1-0.15 g / mL.

[0013] Furthermore, the preparation method of the SH-polyurethane-SiO2 includes the following steps: V1. Under a N2 atmosphere, isophorone diisocyanate (IPDI) was added to toluene and mixed to obtain an IPDI solution. Polypropylene glycol (Mw=400) and dibutyltin dilaurate (DBTDL) were added to toluene and mixed to obtain a mixed solution. The mixed solution was added dropwise to the IPDI solution under an 80°C water bath. After the addition was complete, the reaction was continued for 5-6 h to obtain a polyurethane reaction solution. ; V2. Under N2 atmosphere, nano-SiO2 was added to the polyurethane reaction solution obtained in step V1 and dispersed evenly. The reaction was carried out at 80℃ for 5-6 h. Trimethylolpropane tris(2-mercaptoacetate) and triethylamine were added at room temperature and the reaction was carried out for 1-2 h. The mixture was centrifuged at 5000 rpm for 10-15 min, and the precipitate was washed with toluene and ethanol and dried under vacuum to obtain SH-polyurethane-SiO2. ; .

[0014] Further, in step V1, the molar ratio of isophorone diisocyanate to polypropylene glycol is 2:1.

[0015] Further, in step V1, the molar concentration of the isophorone diisocyanate in toluene is 0.4-0.6 mmol / mL.

[0016] Further, in step V1, the molar concentration of the polypropylene glycol in toluene is 0.6-1 mmol / mL.

[0017] Further, in step V1, the amount of dibutyltin dilaurate used is 0.6-0.8 wt% of the mass of isophorone diisocyanate.

[0018] Furthermore, in step V2, the particle size of the nano-SiO2 is preferably 40-60 nm.

[0019] Furthermore, in step V2, the mass ratio of nano-SiO2 to polypropylene glycol is 1.5-2:1.

[0020] Further, in step V2, the mass ratio of the nano-SiO2, trimethylolpropane tris(2-mercaptoacetate), and triethylamine is 1.5-2:1.2:0.01-0.015.

[0021] Furthermore, the present invention also provides a method for preparing the solid waste-based mine filling composite material, comprising the following steps: S1. Add SH-polyurethane-SiO2 to DMF and disperse evenly. Add triethylamine and epoxy eugenol-HCCP to it. Stir and react at 30-35℃ for 72 h. Filter, wash with DMF and ethanol, and dry. S2. The product obtained in step S1 is mixed with coal gangue, red mud and ordinary silicate cement to obtain a mixture. Polycarboxylate superplasticizer and water are mixed evenly and stirred with the mixture to obtain a solid waste-based mine filling composite material.

[0022] Further, in step S1, the mass concentration of the SH-polyurethane-SiO2 in DMF is 15-20 mg / mL.

[0023] Further, in step S1, the mass ratio of triethylamine to SH-polyurethane-SiO2 is 1:40.

[0024] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a solid waste-based mine backfill composite material and its preparation method. Epoxy-eugenol-HCCP and SH-polyurethane-SiO2 are introduced to construct an organic-inorganic crosslinking network, improving the mechanical properties, freeze-thaw resistance, and flame retardant properties of the backfill composite material, thus realizing the resource utilization of solid waste such as coal gangue and red mud. This invention prepares epoxy-eugenol-HCCP by reacting the phenolic hydroxyl groups in eugenol with the P-Cl groups on hexachlorocyclotriphosphazene to generate eugenol-HCCP containing a multi-arm eugenol structure. The carbon-carbon double bonds in the eugenol side chain are epoxidized using m-chloroperoxybenzoic acid, introducing multiple epoxy active groups to obtain epoxy-eugenol-HCCP with multifunctional crosslinking capabilities, providing reaction sites for subsequent construction of a three-dimensional crosslinking network. This invention prepares SH-polyurethane-SiO2. Isophorone diisocyanate undergoes a polyurethane condensation reaction with polypropylene glycol to form a polyurethane prepolymer. Nano-SiO2 is then introduced, with polyurethane segments grafted onto its surface. Thiol groups are introduced onto the polyurethane-SiO2 surface using trimethylolpropane tris(2-mercaptoacetate), resulting in SH-polyurethane-SiO2 that possesses flexibility, rigidity, and reactivity, providing active sites for subsequent ring-opening crosslinking with epoxy groups. This invention utilizes epoxy-eugenol-HCCP to undergo a thiol-epoxy ring-opening reaction with SH-polyurethane-SiO2, forming a stable chemically crosslinked structure. The epoxy groups in the epoxy-eugenol-HCCP molecule can undergo ring-opening addition with the thiol groups on the surface of SH-polyurethane-SiO2, enabling the organic phase to form a continuous crosslinked network. HCCP provides rigid multifunctional crosslinking nodes, polyurethane segments provide a flexible buffer structure, and nano-SiO2 provides inorganic rigidity reinforcement and nanofilling. The cross-linked reinforcing phase improves particle dispersion stability and reduces nano-SiO2 agglomeration. The rigid phosphazene rings of HCCP act as multifunctional cross-linking nodes, increasing cross-linking density and structural stability. This cross-linked network further intertwines with the gel formed by cement hydration, enhancing the strength, crack resistance, freeze-thaw resistance, and long-term service stability of the filling material. The polyurethane molecular chains possess flexibility and interfacial adhesion, forming a flexible transition layer between cement hydration products and coal gangue / red mud aggregate, effectively dispersing stress concentration under external forces, inhibiting microcrack propagation, and improving the flexural strength of the material. Uniformly dispersed nano-SiO2 in the cross-linked network provides a filling effect, filling capillary pores and structural defects within the matrix, densifying the overall matrix, and improving the mechanical strength of the filling material. The uniformly dispersed SiO2 nanoparticles in the polyurethane network form an interpenetrating structure with the organic network and form hydrogen bonds or interfacial bonds with cement hydration products, enhancing interfacial adhesion. Organic-inorganic interpenetrating networks can effectively bridge the interfaces between coal gangue, red mud and cement hydration products, improve the overall density and load transfer efficiency of the material, and significantly improve the flexural strength and mechanical properties of the filling material.This invention constructs an organic-inorganic crosslinked network. The flexible polyurethane segments possess a certain degree of elasticity, which can buffer the volumetric stress generated during freeze-thaw cycles. Nano-SiO2 can exert a nano-filling effect, making the structure more continuous and dense, reducing free water content and space for ice crystal formation during freeze-thaw cycles. Simultaneously, the crosslinked network can inhibit microcrack propagation, improve interfacial toughness, and enhance the freeze-thaw resistance of the filling material. The flexible polyurethane segments in the crosslinked network can undergo elastic deformation, buffering the expansion stress generated by ice crystal growth and inhibiting the initiation and extension of microcracks. This invention's epoxy-eugenol-HCCP uses hexachlorocyclotriphosphazene as its molecular core framework and is rich in phosphorus and nitrogen flame-retardant elements. During heating, the phosphazene ring can promote the formation of a stable char layer and release phosphorus-containing free radicals to inhibit the combustion chain reaction. SiO2 nanoparticles form a heat-insulating layer at high temperatures, synergistically improving the thermal stability and limiting oxygen index of the material with the flame-retardant effect of phosphazene. The material exhibits good flame-retardant properties, improving the safety of mine filling materials in underground filling projects. Attached Figure Description

[0025] Figure 1 The flexural strength of the composite materials described in Examples 1-3 and Comparative Examples 1-3 of this invention; Figure 2 This describes the freeze-thaw cycle resistance of the composite materials described in Examples 1-3 and Comparative Examples 1-3 of the present invention. Figure 3 The limiting oxygen index is the composite material described in Examples 1-3 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. However, this invention is not limited to the following embodiments. It should be noted that, unless otherwise specified, all chemical reagents involved in this invention are purchased through commercial channels.

[0027] Example 1: A solid waste-based mine filling composite material, the raw materials for which are prepared include the following components in parts by weight: 5 parts of epoxy eugenol-HCCP, 9 parts of SH-polyurethane-SiO2, 40 parts of coal gangue, 30 parts of red mud, 30 parts of 42.5 grade ordinary silicate cement, 50 parts of water, and 0.5 parts of polycarboxylate superplasticizer.

[0028] The particle size of coal gangue is 50 μm, and the particle size of red mud is 60 μm.

[0029] The preparation method of epoxy eugenol-HCCP includes the following steps: L1. Under a nitrogen atmosphere, eugenol was added to dioxane and stirred until dissolved. The mass concentration of eugenol in dioxane was 0.18 g / mL. Then, tetrabutylammonium bromide was added, and the mixture was stirred at room temperature for 30 min. NaOH was then added, and the temperature was raised to 40℃ and maintained for 3 h to obtain a reaction solution. Hexachlorocyclotriphosphazene (HCCP) was dissolved in dioxane. The mass concentration of hexachlorocyclotriphosphazene in dioxane was 0.2 g / mL to obtain an HCCP solution. The mass ratio of eugenol, tetrabutylammonium bromide, NaOH, and hexachlorocyclotriphosphazene was 180:1:44:60. The HCCP solution was added dropwise to the reaction solution, and the mixture was stirred at 70℃ for 48 h. L2. After the reaction in step L1 is completed, cool to room temperature, filter, concentrate the filtrate by rotary evaporation to remove the solvent, dissolve the product in dichloromethane, wash with deionized water and saturated NaCl aqueous solution, dry the organic phase with anhydrous sodium sulfate, filter, remove dichloromethane by rotary evaporation, wash with ethanol, dry, and obtain eugenol-HCCP. L3. The eugenol-HCCP obtained in step L2 was dissolved in dichloromethane, with a mass concentration of 100 mg / mL, to obtain an eugenol-HCCP solution. Then, m-chloroperoxybenzoic acid was added to dichloromethane and mixed thoroughly, with a mass concentration of 0.15 g / mL, to obtain a suspension. The mass ratio of eugenol-HCCP to m-chloroperoxybenzoic acid was 1:1.4. At 4℃, the eugenol-HCCP solution was added dropwise to the suspension. After the addition was complete, the mixture was reacted at 40℃ for 14 h. After the reaction was complete, the mixture was filtered, and the filtrate was washed with saturated Na2S2O3 solution, saturated NaHCO3 solution, saturated NaCl solution, and deionized water. The organic phase was dried with anhydrous sodium sulfate, filtered, and then rotary evaporated and dried under vacuum at 60℃ to obtain epoxy-eugenol-HCCP.

[0030] The preparation method of SH-polyurethane-SiO2 includes the following steps: Under a V1. N2 atmosphere, isophorone diisocyanate (IPDI) was added to toluene and mixed thoroughly. The molar concentration of isophorone diisocyanate in toluene was 0.6 mmol / mL, resulting in an IPDI solution. Separately, polypropylene glycol (Mw=400) and dibutyltin dilaurate (DBTDL) were added to toluene and mixed thoroughly. The molar concentration of polypropylene glycol in toluene was 1 mmol / mL, resulting in a mixed solution. The amount of dibutyltin dilaurate was 0.8 wt% of the mass of isophorone diisocyanate, and the molar ratio of isophorone diisocyanate to polypropylene glycol was 2:1. Under an 80°C water bath, the mixed solution was added dropwise to the IPDI solution. After the addition was complete, the reaction continued for 6 h to obtain a polyurethane reaction solution. Under a V2 atmosphere, 60 nm nano-SiO2 particles were added to the polyurethane reaction solution obtained in step V1 and dispersed evenly. The mass ratio of nano-SiO2 to polypropylene glycol used in step V1 was 2:1. The reaction was carried out at 80℃ for 6 h. Trimethylolpropane tris(2-mercaptoacetate) and triethylamine were added at room temperature. The mass ratio of nano-SiO2, trimethylolpropane tris(2-mercaptoacetate) and triethylamine was 2:1.2:0.015. The reaction was carried out for 2 h. After centrifugation at 5000 rpm for 15 min, the precipitate was washed with toluene and ethanol and dried under vacuum to obtain SH-polyurethane-SiO2.

[0031] This embodiment also provides a method for preparing the solid waste-based mine filling composite material, including the following steps: S1. SH-polyurethane-SiO2 was added to DMF and dispersed evenly. The mass concentration of SH-polyurethane-SiO2 in DMF was 20 mg / mL. Triethylamine and epoxy eugenol-HCCP were added to it. The mass ratio of triethylamine to SH-polyurethane-SiO2 was 1:40. The mixture was stirred at 35℃ for 72 h. After filtration, the mixture was washed with DMF and ethanol and dried. S2. The product obtained in step S1 is mixed with coal gangue, red mud and ordinary silicate cement to obtain a mixture. Polycarboxylate superplasticizer and water are mixed evenly and stirred with the mixture to obtain a solid waste-based mine filling composite material.

[0032] Example 2: A solid waste-based mine filling composite material, the raw materials for which are prepared include the following components in parts by weight: 3 parts epoxy eugenol-HCCP, 6 parts SH-polyurethane-SiO2, 30 parts coal gangue, 20 parts red mud, 20 parts 42.5 grade ordinary silicate cement, 40 parts water, and 0.3 parts polycarboxylate superplasticizer.

[0033] The particle size of the coal gangue is 40 μm, and the particle size of the red mud is 40 μm.

[0034] The preparation method of epoxy eugenol-HCCP includes the following steps: L1. Under a nitrogen atmosphere, eugenol was added to dioxane and stirred until dissolved. The mass concentration of eugenol in dioxane was 0.15 g / mL. Then, tetrabutylammonium bromide was added, and the mixture was stirred at room temperature for 30 min. NaOH was then added, and the temperature was raised to 40℃ and maintained for 3 h to obtain a reaction solution. Hexachlorocyclotriphosphazene (HCCP) was dissolved in dioxane. The mass concentration of hexachlorocyclotriphosphazene in dioxane was 0.15 g / mL to obtain an HCCP solution. The mass ratio of eugenol, tetrabutylammonium bromide, NaOH, and hexachlorocyclotriphosphazene was 180:1:44:60. The HCCP solution was added dropwise to the reaction solution, and the mixture was stirred at 70℃ for 48 h. L2. After the reaction in step L1 is completed, cool to room temperature, filter, concentrate the filtrate by rotary evaporation to remove the solvent, dissolve the product in dichloromethane, wash with deionized water and saturated NaCl aqueous solution, dry the organic phase with anhydrous sodium sulfate, filter, remove dichloromethane by rotary evaporation, wash with ethanol, dry, and obtain eugenol-HCCP. L3. The eugenol-HCCP obtained in step L2 was dissolved in dichloromethane, and the mass concentration of eugenol-HCCP in dichloromethane was 60 mg / mL, to obtain an eugenol-HCCP solution. m-Cloroperoxybenzoic acid was added to dichloromethane and mixed well, and the mass concentration of m-Cloroperoxybenzoic acid in dichloromethane was 0.1 g / mL, to obtain a suspension. The mass ratio of eugenol-HCCP to m-Cloroperoxybenzoic acid was 1:1.2. At 0℃, the eugenol-HCCP solution was added dropwise to the suspension. After the addition was complete, the reaction was carried out at 40℃ for 12 h. After the reaction was completed, the mixture was filtered, and the filtrate was washed with saturated Na2S2O3 solution, saturated NaHCO3 solution, saturated NaCl solution, and deionized water. The organic phase was dried with anhydrous sodium sulfate, filtered, and then rotary evaporated and dried under vacuum at 60℃ to obtain epoxy-eugenol-HCCP.

[0035] The preparation method of SH-polyurethane-SiO2 includes the following steps: Under a V1. N2 atmosphere, isophorone diisocyanate (IPDI) was added to toluene and mixed thoroughly. The molar concentration of isophorone diisocyanate in toluene was 0.4 mmol / mL, resulting in an IPDI solution. Separately, polypropylene glycol (Mw=400) and dibutyltin dilaurate (DBTDL) were added to toluene and mixed thoroughly. The molar concentration of polypropylene glycol in toluene was 0.6 mmol / mL, resulting in a mixed solution. The amount of dibutyltin dilaurate was 0.6 wt% of the mass of isophorone diisocyanate, and the molar ratio of isophorone diisocyanate to polypropylene glycol was 2:1. Under an 80°C water bath, the mixed solution was added dropwise to the IPDI solution. After the addition was complete, the reaction was continued for 5 h to obtain a polyurethane reaction solution. Under a V2 atmosphere, 40 nm nano-SiO2 particles were added to the polyurethane reaction solution obtained in step V1 and dispersed evenly. The mass ratio of nano-SiO2 to polypropylene glycol used in step V1 was 1.5:1. The reaction was carried out at 80℃ for 5 h. Trimethylolpropane tris(2-mercaptoacetate) and triethylamine were added at room temperature. The mass ratio of nano-SiO2, trimethylolpropane tris(2-mercaptoacetate) and triethylamine was 1.5:1.2:0.01. The reaction was carried out for 1 h. The mixture was centrifuged at 5000 rpm for 10 min. The precipitate was washed with toluene and ethanol and dried under vacuum to obtain SH-polyurethane-SiO2.

[0036] This embodiment also provides a method for preparing the solid waste-based mine filling composite material, including the following steps: S1. SH-polyurethane-SiO2 was added to DMF and dispersed evenly. The mass concentration of SH-polyurethane-SiO2 in DMF was 15 mg / mL. Triethylamine and epoxy eugenol-HCCP were added to it. The mass ratio of triethylamine to SH-polyurethane-SiO2 was 1:40. The mixture was stirred at 30℃ for 72 h. After filtration, the mixture was washed with DMF and ethanol and dried. S2. The product obtained in step S1 is mixed with coal gangue, red mud and ordinary silicate cement to obtain a mixture. Polycarboxylate superplasticizer and water are mixed evenly and stirred with the mixture to obtain a solid waste-based mine filling composite material.

[0037] Example 3: A solid waste-based mine filling composite material, the raw materials for which are prepared include the following components in parts by weight: 4 parts epoxy eugenol-HCCP, 8 parts SH-polyurethane-SiO2, 35 parts coal gangue, 25 parts red mud, 25 parts 42.5 grade ordinary silicate cement, 45 parts water, and 0.4 parts polycarboxylate superplasticizer.

[0038] The particle size of coal gangue is 45μm, and the particle size of red mud is 50μm.

[0039] The preparation method of epoxy eugenol-HCCP includes the following steps: L1. Under a nitrogen atmosphere, eugenol was added to dioxane and stirred until dissolved. The mass concentration of eugenol in dioxane was 0.16 g / mL. Then, tetrabutylammonium bromide was added, and the mixture was stirred at room temperature for 30 min. NaOH was then added, and the temperature was raised to 40℃ and maintained for 3 h to obtain a reaction solution. Hexachlorocyclotriphosphazene (HCCP) was dissolved in dioxane. The mass concentration of hexachlorocyclotriphosphazene in dioxane was 0.18 g / mL to obtain an HCCP solution. The mass ratio of eugenol, tetrabutylammonium bromide, NaOH, and hexachlorocyclotriphosphazene was 180:1:44:60. The HCCP solution was added dropwise to the reaction solution, and the mixture was stirred at 70℃ for 48 h. L2. After the reaction in step L1 is completed, cool to room temperature, filter, concentrate the filtrate by rotary evaporation to remove the solvent, dissolve the product in dichloromethane, wash with deionized water and saturated NaCl aqueous solution, dry the organic phase with anhydrous sodium sulfate, filter, remove dichloromethane by rotary evaporation, wash with ethanol, dry, and obtain eugenol-HCCP. L3. The eugenol-HCCP obtained in step L2 was dissolved in dichloromethane. The mass concentration of eugenol-HCCP in dichloromethane was 80 mg / mL, resulting in an eugenol-HCCP solution. m-Cloroperoxybenzoic acid was added to dichloromethane and mixed thoroughly. The mass concentration of m-Cloroperoxybenzoic acid in dichloromethane was 0.12 g / mL, resulting in a suspension. The mass ratio of eugenol-HCCP to m-Cloroperoxybenzoic acid was 1:1.3. At 2℃, the eugenol-HCCP solution was added dropwise to the suspension. After the addition was complete, the mixture was reacted at 40℃ for 13 h. After the reaction was complete, the mixture was filtered. The filtrate was washed with saturated Na2S2O3 solution, saturated NaHCO3 solution, saturated NaCl solution, and deionized water. The organic phase was dried with anhydrous sodium sulfate, filtered, and then rotary evaporated. The solution was then vacuum dried at 60℃ to obtain epoxy-eugenol-HCCP.

[0040] The preparation method of SH-polyurethane-SiO2 includes the following steps: Under a V1. N2 atmosphere, isophorone diisocyanate (IPDI) was added to toluene and mixed thoroughly. The molar concentration of isophorone diisocyanate in toluene was 0.5 mmol / mL, resulting in an IPDI solution. Separately, polypropylene glycol (Mw=400) and dibutyltin dilaurate (DBTDL) were added to toluene and mixed thoroughly. The molar concentration of polypropylene glycol in toluene was 0.8 mmol / mL, resulting in a mixed solution. The amount of dibutyltin dilaurate was 0.7 wt% of the mass of isophorone diisocyanate, and the molar ratio of isophorone diisocyanate to polypropylene glycol was 2:1. Under an 80°C water bath, the mixed solution was added dropwise to the IPDI solution. After the addition was complete, the reaction continued for 5.5 h to obtain a polyurethane reaction solution. Under a V2 atmosphere, 50 nm nano-SiO2 particles were added to the polyurethane reaction solution obtained in step V1 and dispersed evenly. The mass ratio of nano-SiO2 to polypropylene glycol used in step V1 was 1.8:1. The reaction was carried out at 80℃ for 5.5 h. Trimethylolpropane tris(2-mercaptoacetate) and triethylamine were added at room temperature. The mass ratio of nano-SiO2, trimethylolpropane tris(2-mercaptoacetate) and triethylamine was 1.8:1.2:0.012. The reaction was carried out for 1.5 h. The mixture was centrifuged at 5000 rpm for 12 min. The precipitate was washed with toluene and ethanol and dried under vacuum to obtain SH-polyurethane-SiO2.

[0041] This embodiment also provides a method for preparing the solid waste-based mine filling composite material, including the following steps: S1. SH-polyurethane-SiO2 was added to DMF and dispersed evenly. The mass concentration of SH-polyurethane-SiO2 in DMF was 18 mg / mL. Triethylamine and epoxy eugenol-HCCP were added to it. The mass ratio of triethylamine to SH-polyurethane-SiO2 was 1:40. The mixture was stirred at 32℃ for 72 h. After filtration, the mixture was washed with DMF and ethanol and dried. S2. The product obtained in step S1 is mixed with coal gangue, red mud and ordinary silicate cement to obtain a mixture. Polycarboxylate superplasticizer and water are mixed evenly and stirred with the mixture to obtain a solid waste-based mine filling composite material.

[0042] The only difference between Comparative Example 1 and Example 1 is that epoxy eugenol-HCCP is not added.

[0043] The only difference between Comparative Example 2 and Example 1 is that SH-polyurethane-SiO2 is not added.

[0044] The only difference between Comparative Example 3 and Example 1 is that nano-SiO2 is used instead of SH-polyurethane-SiO2.

[0045] Experimental Example 1: Filled composite materials were prepared according to the methods of Examples 1-3 and Comparative Examples 1-3. The composites were injected into a 40 mm × 40 mm × 160 mm mold, cured at a humidity > 90% and a temperature of 20 ± 1℃ for 24 h, then demolded. Curing continued until 28 days of age. Flexural strength was tested, and the results are as follows: Figure 1 As shown.

[0046] Figure 1 The results showed that the flexural strength of Examples 1-3 was superior to that of Comparative Examples 1-3. Comparative Example 1 did not add epoxy eugenol-HCCP, Comparative Example 2 did not add SH-polyurethane-SiO2, and Comparative Example 3 used nano-SiO2 instead of SH-polyurethane-SiO2, all of which resulted in a decrease in flexural strength. The thiol-epoxy click reaction between the polyepoxy groups of epoxy eugenol-HCCP and the abundant thiol groups on the surface of SH-polyurethane-SiO2 constructs an organic-inorganic cross-linked structure, improving flexural strength. Comparative Examples 1-3 lacked the cross-linking component, resulting in a decrease in flexural strength. Nano-SiO2 can act as a rigidity reinforcement point, improving flexural strength; the absence of nano-SiO2 components resulted in a decrease in flexural strength.

[0047] Experimental Example 2: Specimens cured for 28 days were subjected to a rapid freeze-thaw cycle test. One cycle consisted of freezing at -20℃ for 4 hours and thawing at 20℃ for 4 hours. The mass loss rate after 100 cycles was measured, and the results are as follows: Figure 2 As shown.

[0048] Figure 2The results showed that the freeze-thaw resistance of Examples 1-3 was superior to that of Comparative Examples 1-3. Comparative Example 1 did not add epoxy eugenol-HCCP, Comparative Example 2 did not add SH-polyurethane-SiO2, and Comparative Example 3 used nano-SiO2 instead of SH-polyurethane-SiO2. After freeze-thaw cycles, the mass loss rate increased, and the freeze-thaw resistance decreased. The cross-linked network constructed by epoxy eugenol-HCCP and SH-polyurethane-SiO2 through a thiol-epoxy click reaction can effectively block the capillary channels through which water permeates into the material. The benzene ring in the eugenol molecule of the epoxy eugenol-HCCP raw material imparts a certain degree of hydrophobicity to the cross-linked system, reducing the saturated water absorption rate of the filler and significantly reducing the content of freezeable free water. The nano-SiO2 core provides rigid support points, and the flexible polypropylene glycol segments grafted on the surface can effectively prevent the initiation and propagation of microcracks during freeze-thaw cycles, ensuring the integrity of the structure.

[0049] Experimental Example 3: The limiting oxygen index (LOI) of the material was tested using specimens cured for 28 days. The results are as follows: Figure 3 As shown.

[0050] Figure 3 The results showed that the limiting oxygen index of Examples 1-3 was higher than that of Comparative Examples 1-3. Comparative Example 1 did not add epoxy eugenol-HCCP, Comparative Example 2 did not add SH-polyurethane-SiO2, and Comparative Example 3 used nano-SiO2 instead of SH-polyurethane-SiO2; all of these resulted in a decrease in limiting oxygen index and flame retardant performance. The epoxy eugenol-HCCP molecule has a phosphazene ring structure of hexachlorocyclotriphosphazene at its center, forming a high-performance phosphorus-nitrogen flame retardant framework. The nano-SiO2 component can form a protective layer at high temperatures, improving the flame retardant effect.

[0051] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A solid waste-based mine filling composite material, characterized in that, The raw materials for preparation include the following components in parts by weight: 2-3 parts epoxy eugenol-HCCP, 4-6 parts SH-polyurethane-SiO2, 30-40 parts coal gangue, 20-30 parts red mud, 20-30 parts grade 42.5 ordinary silicate cement, 40-50 parts water, and 0.3-0.5 parts polycarboxylate superplasticizer; The preparation method of epoxy eugenol-HCCP includes the following steps: L1. Under a nitrogen atmosphere, eugenol was added to dioxane and stirred until dissolved. Then tetrabutylammonium bromide was added and stirred at room temperature. NaOH was then added and the temperature was raised to 40°C to obtain a reaction solution. Hexachlorocyclotriphosphazene was dissolved in dioxane to obtain an HCCP solution. The HCCP solution was added dropwise to the reaction solution and stirred at 70°C. L2. After the reaction in step L1 is complete, the mixture is cooled, filtered, rotary evaporated, dissolved in dichloromethane, washed, dried, rotary evaporated, washed, and dried to obtain eugenol-HCCP; L3. Dissolve the eugenol-HCCP obtained in step L2 in dichloromethane to obtain an eugenol-HCCP solution. Add m-chloroperoxybenzoic acid to dichloromethane and mix well to obtain a suspension. Add the eugenol-HCCP solution dropwise to the suspension at 0-4℃. After the addition is complete, react at 40℃, filter, wash, dry, rotary evaporate, and dry again to obtain epoxy eugenol-HCCP. The preparation method of SH-polyurethane-SiO2 includes the following steps: V1. Under a N2 atmosphere, isophorone diisocyanate was added to toluene and mixed to obtain an IPDI solution. Polypropylene glycol and dibutyltin dilaurate were added to toluene and mixed to obtain a mixed solution. The mixed solution was added dropwise to the IPDI solution under an 80°C water bath. After the addition was complete, the reaction was carried out to obtain a polyurethane reaction solution. V2. Under N2 atmosphere, nano-SiO2 was added to the polyurethane reaction solution obtained in step V1 and dispersed evenly. The reaction was carried out at 80℃. Trimethylolpropane tris(2-mercaptoacetate) and triethylamine were added at room temperature. The reaction was carried out, centrifuged, washed, and dried to obtain SH-polyurethane-SiO2.

2. The solid waste-based mine filling composite material according to claim 1, characterized in that, The coal gangue has a particle size of 40-50 μm, and the red mud has a particle size of 40-60 μm.

3. The solid waste-based mine filling composite material according to claim 2, characterized in that, In step L1, the mass ratio of eugenol, tetrabutylammonium bromide, NaOH, and hexachlorocyclotriphosphazene is 180:1:44:

60.

4. The solid waste-based mine filling composite material according to claim 3, characterized in that, In step L3, the mass ratio of eugenol-HCCP to m-chloroperoxybenzoic acid is 1:1.2-1.

4.

5. The solid waste-based mine filling composite material according to claim 4, characterized in that, In step V1, the molar ratio of isophorone diisocyanate to polypropylene glycol is 2:

1.

6. The solid waste-based mine filling composite material according to claim 5, characterized in that, In step V1, the amount of dibutyltin dilaurate used is 0.6-0.8 wt% of the mass of isophorone diisocyanate.

7. The solid waste-based mine filling composite material according to claim 6, characterized in that, In step V2, the particle size of the nano-SiO2 is 40-60 nm.

8. The solid waste-based mine filling composite material according to claim 7, characterized in that, In step V2, the mass ratio of nano-SiO2 to polypropylene glycol is 1.5-2:

1.

9. The solid waste-based mine filling composite material according to claim 8, characterized in that, In step V2, the mass ratio of nano-SiO2, trimethylolpropane tris(2-mercaptoacetate) and triethylamine is 1.5-2:1.2:0.01-0.

015.

10. A method for preparing a solid waste-based mine filling composite material as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Add SH-polyurethane-SiO2 to DMF and disperse evenly. Add triethylamine and epoxy eugenol-HCCP to it. Stir and react at 30-35℃. Filter, wash and dry. S2. The product obtained in step S1 is mixed with coal gangue, red mud and ordinary silicate cement to obtain a mixture. Polycarboxylate superplasticizer and water are mixed evenly and stirred with the mixture to obtain a solid waste-based mine filling composite material.

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