A rapid prototyping quick-setting inorganic spray material, a preparation method and application thereof

Abstract

This invention belongs to the technical field of inorganic spraying materials for mining, specifically a rapid-forming and quick-setting inorganic spraying material, its preparation method, and its application. Addressing the spontaneous combustion problem in existing top-coal caving mining techniques, this application proposes a method for coating the sides of a single-layer metal mesh during the final stage of mesh laying in the working face. This involves applying the mesh-laying and sealing method to the final stage of mesh laying to reduce spontaneous combustion of coal caused by air leakage in the working face. Furthermore, the rapid-forming and quick-setting inorganic spraying material of this invention has advantages such as quick application, high adhesion, good film-forming properties, good flame retardancy, good mechanical stability, and good chemical stability.

Description

Technical Field

[0001] This invention belongs to the technical field of inorganic spraying materials for mining, specifically a rapid-forming and quick-setting inorganic spraying material, its preparation method, and its application. Background Technology

[0002] Spontaneous combustion of coal is a natural disaster that causes significant economic losses and is also an important issue in coal mine safety. According to statistics, 72.9% of large and medium-sized coal mines have a serious or relatively serious risk of spontaneous combustion, while 47.3% of key state-owned coal mines have this risk; the proportion is even higher in small coal mines, reaching 85.3%. Since France adopted top-coal caving mining technology as the main method for mining thick coal seams in 1962, this technology has been widely used worldwide.

[0003] In recent years, my country has widely adopted fully mechanized top-coal caving mining technology. After years of experimental research and field application, this technology has reached a world-leading level. However, there are still some problems that urgently need to be solved. Compared with ordinary mechanized coal mining, the machinery used in top-coal caving mining, such as hydraulic supports, has longer equipment frames, heavier tonnage, longer dismantling time, and more equipment, resulting in a longer time required for stopping mining and removing supports. Furthermore, since the top coal is not released before the working face is stopped in top-coal caving mining, the goaf has a large amount of air leakage and residual coal, making it extremely easy for spontaneous combustion to occur in the goaf during the shutdown and support removal period. Spontaneous combustion of coal can destroy a large amount of coal resources; every year, more than ten million tons of high-quality coal resources are lost due to mine fires. The number of working faces closed due to fires in my country's key state-owned coal mines is increasing year by year, exceeding 100 annually. This closure renders fully mechanized mining and top-coal caving equipment unusable, freezes large amounts of coal, and seriously affects the mining sequence and production deployment. At the same time, fires also bring huge safety hazards to coal mine production and cause huge economic losses to enterprises. In addition, spontaneous combustion of coal produces a large amount of toxic and harmful gases, which seriously endanger the lives of underground personnel and cause serious pollution to the atmospheric environment.

[0004] Currently, the problem of spontaneous combustion of coal during the shutdown and removal of supports in the final stage of mining faces exists in all major coal-producing areas of my country. In the past, various materials such as fly ash and accelerators were used to construct sealing walls in the intake and return airways, and roof netting was laid during the final stage of mining faces. However, this method cannot completely stop air leakage, especially the sealing of the working face still has defects, and it is time-consuming and requires a large amount of human resources. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, the purpose of this invention is to provide a rapidly forming and quick-setting inorganic spraying material, its preparation method, and its application. This application addresses the spontaneous combustion problem in existing top-coal caving mining techniques by proposing a method of applying a rapidly forming and quick-setting inorganic spraying material to both sides of a single-layer metal mesh during the final stage of mesh laying in the working face. This method utilizes the mesh laying and skinning method for sealing during the final stage of mesh laying, thereby reducing the problem of spontaneous combustion of coal caused by air leakage in the working face. Furthermore, the rapidly forming and quick-setting inorganic spraying material of this invention has advantages such as quick construction, high adhesion, good film-forming properties, good flame retardancy, good mechanical stability, and good chemical stability.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0007] Currently, in the final stage of underground working faces, due to the time required for shutdown and support removal, the coal body above and behind the supports remains in a stable state of air leakage and oxygen supply for an extended period, making it highly susceptible to spontaneous combustion. Therefore, sealing is required in the goaf and working faces. Previously, this was achieved by constructing airtight walls on both sides of the intake and return airways. This invention provides a rapid-forming, quick-setting inorganic spraying material for use in the final stage of working faces prone to spontaneous combustion. This material has flame-retardant properties, good airtightness, and does not impair other performance parameters. It can form a complete seal over the entire working face during the meshing stage, integrating with the airtight walls of the intake and return airways to create a membrane barrier between the goaf and the working face. This isolates the coal body above and behind the supports from the goaf, ensuring good isolation between the goaf and the working face in the final stage of mining.

[0008] Based on the deficiencies of existing technologies and the aforementioned technical considerations, this application adopts a combined sealing method of mesh and film across the entire working face. After the metal mesh is laid on the support, it is buried in the goaf, and a rapid-forming and quick-setting inorganic coating material is sprayed on both sides of the mesh. The use of flame-retardant, highly airtight, mechanically stable, and chemically stable membrane-covered isolation mesh overcomes the aforementioned technical deficiencies, effectively achieving the isolation between the goaf and the coal mining face, greatly reducing air leakage, and preventing coal spontaneous combustion and mine fires.

[0009] A rapid-forming and quick-setting inorganic spraying material comprises the following raw materials in parts by weight: 30-50 parts silica sol, 15-35 parts water-based acrylic emulsion, and 8-15 parts flame retardant.

[0010] Preferably, the silica sol is an alkaline silica sol, which has strong stability and produces products with high strength and high durability.

[0011] Preferably, the aqueous acrylic emulsion is selected from one or a mixture of several of water-emulsion acrylic resins, water-dispersible acrylic resins, and water-soluble acrylic resins. "Aqueous" means that water is used as a solvent or dispersion medium, which has good stability and is environmentally friendly.

[0012] Preferably, the flame retardant is composed of magnesium hydroxide, aluminum hydroxide, ultrafine encapsulated red phosphorus FR-85, and potassium oleate in a mass ratio of 1:1:2-3:1-2.

[0013] This invention also protects a method for preparing a rapid-forming, quick-setting inorganic spraying material, comprising the following steps:

[0014] Magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-encapsulated red phosphorus FR-85 are mixed evenly and then mixed with potassium oleate to prepare a flame retardant.

[0015] Silica sol, water-based acrylic emulsion, and flame retardant are mixed evenly to obtain a rapid-forming and quick-setting inorganic spraying material.

[0016] Preferably, the product also includes the following raw materials in parts by weight: 4-10 parts film-forming aid, 3-6 parts surfactant, 1-2 parts thickener, 1-3 parts dispersant, 1-3 parts defoamer, 0-1.5 parts antistatic agent, 2.5-6.5 parts carbon black, and 10-20 parts water.

[0017] Preferably, the film-forming aid is dodecyl alcohol ester; the surfactant is fatty alcohol polyoxyethylene ether; the thickener is polyvinyl alcohol; the dispersant is water glass; the defoamer is trioctyl phosphate; the antistatic agent is sodium alkyl sulfonate; and the carbon black is semi-reinforcing carbon black N754.

[0018] Furthermore, the preparation method of the rapid prototyping and quick-setting inorganic spraying material includes the following steps:

[0019] Magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-encapsulated red phosphorus FR-85 were mixed evenly and then mixed with potassium oleate to prepare a flame retardant.

[0020] Water, surfactant, dispersant, defoamer, antistatic agent, and silica sol are stirred in sequence until homogeneous to obtain mixture I;

[0021] The thickener was mixed with the aqueous acrylic emulsion to obtain mixture II;

[0022] The flame retardant, mixture I, and mixture II are mixed, and carbon black is added. Then, a film-forming aid is added under stirring conditions. After stirring until uniform, the mixture is filtered to obtain a rapid-forming and quick-setting inorganic spraying material.

[0023] This invention also protects the application of rapidly prototyping and quick-setting inorganic spraying materials in the preparation of fire-prone, self-igniting working surface uncoated partition mesh.

[0024] Preferably, the application method is as follows:

[0025] A single layer of metal mesh is obtained by fixing each two adjacent metal meshes together with steel wire ropes.

[0026] The single-layer metal mesh is laid on top of the support, and the beginning of the steel wire rope is fixed to the reinforcing anchor cable of the roadway shoulder cavity with a treasury clip.

[0027] During the laying of the mesh in the working face, a rapid-forming and quick-setting inorganic spraying material is sprayed onto the top surface of the laid single-layer metal mesh to form an upper film, creating a relative isolation between the working face and the goaf. Then, the support is moved, and a rapid-forming and quick-setting inorganic spraying material is sprayed onto the bottom surface of the single-layer metal mesh to form a lower film, thus forming a membrane-covered isolation mining mesh with a metal mesh as the skeleton and an inorganic material as the film.

[0028] After the entire working face is completely enclosed by a membrane-covered partition mesh, the ends of the steel wire ropes are secured to the reinforcing anchor cables in the roadway shoulder using clips. Then, the support structure is removed from the working face. This is a method for laying and removing mesh in underground mine working faces. The principle behind this method is that spraying is performed during the mesh laying process. Each time the support is moved, the single-layer metal mesh moves a certain distance backward, eventually burying itself underground in the goaf, forming a membrane-covered partition between the goaf and the unmined working face.

[0029] Compared with the prior art, the beneficial effects of this application are as follows:

[0030] 1. The materials used in the preparation process of the rapid-forming and quick-setting inorganic spraying material of this invention have advantages such as being environmentally friendly, energy-saving, and inexpensive; and the rapid-forming and quick-setting inorganic spraying material of this invention has good flame retardant properties after film formation, with a flame retardant rating of B1; the gas permeability and sealing performance indicate that the film has excellent airtightness; the aging tensile, aging crack, and adhesion data show that the rapid-forming and quick-setting inorganic spraying material of this application has a stable structure, which makes it suitable for application in the final stage of mesh laying and film covering of easily self-igniting working faces.

[0031] 2. This invention provides a rapidly forming and quick-setting inorganic spraying material for the mesh covering and sealing of easily self-igniting working faces in the final stage of mining. Judging from the gelation time, this material can quickly form a film, effectively sealing the goaf and the coal face in the final stage of mining. Moreover, the film formed has excellent properties such as high flexibility, high wear resistance, anti-aging, anti-corrosion, and antistatic properties.

[0032] 3. The method proposed in this invention is carried out simultaneously during the netting and support removal process in the final mining stage. It is convenient to operate, fast to achieve, and can quickly form a full working face seal with good results. It greatly reduces air leakage caused by the long support removal time in the past, effectively prevents coal spontaneous combustion and mine fires, reduces the risk of spontaneous combustion of coal in the goaf in the final mining stage, and improves the accuracy of close-range control of dangerous areas. Attached Figure Description

[0033] Figure 1 A schematic diagram of the laying structure of the mesh for the non-filmed partition wall of a work surface prone to spontaneous combustion.

[0034] Figure 2 When using mesh for isolation in a fire-prone working face without a protective film, a frontal view diagram should be drawn showing the positional relationship of the mesh laid within the working face.

[0035] Figure 3 This is a side view diagram showing the positional relationship between the coal seam and the goaf when using a non-coated mesh for self-ignition working faces.

[0036] Figure 4 A top-view diagram showing the relative positions of the mesh laid between the coal seam and the goaf when used as a non-coated barrier in a spontaneously combustible working face.

[0037] Explanation of reference numerals in the attached figures

[0038] 1-Upper membrane, 2-Lower membrane, 3-Metal mesh, 4-Support, 5-Sprayer. Detailed Implementation

[0039] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the present invention are all conventional products that can be purchased commercially.

[0040] (1) This application applies a rapid-forming and quick-setting inorganic spraying material to the mesh-covered partition of the end of the mining face in the case of spontaneous combustion. The main body of the partition is a metal mesh that has been covered with a membrane. The membrane is the skin and the metal mesh is the skeleton. This is the mesh-covered skin technology, which is used to separate the goaf from the coal mining face and to seal it. The main purpose is to prevent air leakage. In addition, it has flame retardant properties, so it can reduce the problem of spontaneous combustion.

[0041] In addition, the silica sol, as the main component in this application, is an inorganic material. Flame retardants and dispersants are also inorganic. Only the aqueous acrylic emulsion is an organic material. Based on this, the product of this application is mainly composed of inorganic materials, so it is named a rapid prototyping and quick-setting inorganic spraying material.

[0042] (2) The present invention is used in the rapid-forming and quick-setting inorganic spraying material for the final-layer mesh covering and partitioning of easily self-igniting working surfaces:

[0043] Silica sol: The main inorganic spraying material, with strong adhesion and high temperature resistance (1500℃-1600℃), has functions such as anti-fouling and dustproofing, aging resistance, and fire resistance. The film formed by silica sol also has good antistatic properties and can be used for underground construction operations.

[0044] Water-based acrylic emulsions have excellent corrosion resistance, weather resistance, water resistance, alkali resistance, good film formation, and good color retention. They are also easy to formulate into coatings with good workability, are environmentally friendly, and safe to use. They can be used as an auxiliary film-forming agent for silica sol to overcome the disadvantages of silica sol film formation, such as large shrinkage and easy cracking of the film.

[0045] Film-forming aids: help inorganic spray materials form films, lower the minimum film-forming temperature, improve application performance and enhance storage stability.

[0046] Surfactants: significantly reduce the surface tension of colloids.

[0047] Dispersants: improve and enhance the colloidal dispersion properties.

[0048] Defoamers: can reduce the surface tension of colloids, prevent foam formation, or reduce or eliminate existing foam.

[0049] Antistatic agent: Eliminates static electricity.

[0050] Thickeners: increase the viscosity of the colloidal substance, improve processing performance, and ensure the stability of the construction process.

[0051] Carbon black: Increases air tightness. The use of semi-reinforcing carbon black N754 (low-structure semi-reinforcing furnace black) can effectively enhance the air tightness of colloids.

[0052] Flame retardants: Aluminum hydroxide and magnesium hydroxide both have advantages such as reducing smoke during plastic combustion, low price, safety and non-toxicity, and good thermal stability during high-temperature processing. When used in combination, they complement each other, resulting in a better flame retardant effect than when used alone. Red phosphorus is an excellent inorganic flame retardant and a common flame retardant synergist in aluminum hydroxide / magnesium hydroxide flame retardant systems. Red phosphorus has high flame retardant efficiency, low dosage, low smoke production, and low toxicity, making it widely applicable. The ultrafine encapsulated red phosphorus FR-85 used here overcomes the disadvantages of ordinary red phosphorus, such as easy oxidation, moisture absorption, potential for dust explosions, and difficulty in transportation. It has advantages such as low smoke, no strange odor, no toxic gas production during processing, and low required dosage. Furthermore, its dispersibility, physical and mechanical properties, thermal stability, and flame retardant properties are all improved. Potassium oleate, as an emulsifier, has good emulsifying properties and stability, as well as a plasticizing effect, which can improve the softness and extensibility of the product. Here, it can be used as a carrier for the above-mentioned flame retardant, and mixed to form a flame retardant dispersion, which can be well miscible with silica sol and water-based acrylic emulsion.

[0053] This invention mixes silica sol, aqueous acrylic emulsion, and flame retardant to prepare a rapid-forming and quick-setting inorganic spraying material. The aqueous acrylic emulsion is added to the silica sol as an auxiliary film-forming agent, allowing organic matter to fill the "—Si—O—Si—" network structure, reducing film shrinkage and expansion / contraction caused by temperature differences. The flame retardant is prepared by mixing potassium oleate as a flame retardant carrier to form a flame retardant dispersion, which can be well miscible with silica sol and aqueous acrylic emulsion.

[0054] (3) The present invention also mixes silica sol, aqueous acrylic emulsion, flame retardant, film-forming aid, surfactant, thickener, dispersant, defoamer, antistatic agent and carbon black to prepare rapid molding and quick-setting inorganic spraying material. The comprehensive performance of rapid molding and quick-setting inorganic spraying material is improved by using film-forming aid, surfactant, thickener, dispersant, defoamer, antistatic agent and carbon black.

[0055] (4) In the production process of the rapid-forming and quick-setting inorganic spraying material for the non-fired working face mesh covering partition of the present invention, the following should also be noted:

[0056] 1. The amount of film-forming aid added should not be too much, and the addition process should be slow dripping, otherwise flocculation is likely to occur; silica sol should also be added slowly, otherwise the material will undergo qualitative changes.

[0057] 2. The optimal shelf life of water-based acrylic emulsion is six months. It must be stirred evenly before use. If it is left for too long, sediment will form at the bottom of the packaging container. Stirring it evenly will not affect the effect. The product must be sealed and protected from direct sunlight and rain.

[0058] The technical solution is explained and illustrated below using examples, as detailed below:

[0059] Example 1

[0060] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0061] (1) Weighing:

[0062] Weigh the following raw materials according to the following weight proportions: 40 parts alkaline silica sol, 15 parts water-based acrylic emulsion, 5 parts dodecyl alcohol ester, 4 parts fatty alcohol polyoxyethylene ether, 1.6 parts polyvinyl alcohol, 2 parts water glass, 1 part trioctyl phosphate, 1.4 parts sodium alkyl sulfonate, 46 parts carbon black N75, 8 parts flame retardant, and 16 parts water.

[0063] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:2:1.

[0064] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0065] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0066] S2. Add 16 parts of water to a container, and then add 4 parts of fatty alcohol polyoxyethylene ether, 2 parts of water glass, 1 part of trioctyl phosphate, 1.4 parts of sodium alkyl sulfonate, and then add 40 parts of alkaline silica sol. Stir well to obtain mixture I.

[0067] S3. Add 1.6 parts of thickener to 15 parts of water-based acrylic emulsion and stir until evenly mixed to obtain mixture II;

[0068] S4. Simultaneously mix the flame retardant, mixture I, and mixture II from steps S1, S2, and S3, and add 6 parts of carbon black N754. Slowly add 5 parts of dodecyl alcohol ester under stirring conditions, and continuously stir at low speed until uniform. Then filter to obtain a fast-forming and quick-setting inorganic spraying material.

[0069] Example 2

[0070] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0071] (1) Weighing:

[0072] Weigh the raw materials according to the following proportions by weight: 35 parts alkaline silica sol, 18 parts water-based acrylic emulsion, 7 parts dodecyl alcohol ester, 3 parts fatty alcohol polyoxyethylene ether, 2 parts polyvinyl alcohol, 2 parts water glass, 1 part trioctyl phosphate, 1 part sodium alkyl sulfonate, 5.5 parts carbon black N754, 10.5 parts flame retardant, and 15 parts water.

[0073] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:2:1.

[0074] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0075] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0076] S2. Add 15 parts of water to a container, and then add 3 parts of fatty alcohol polyoxyethylene ether, 2 parts of water glass, 1 part of trioctyl phosphate, 1 part of sodium alkyl sulfonate, and 35 parts of alkaline silica sol. Stir well to obtain mixture I.

[0077] S3. Add 2 parts of thickener to 18 parts of water-based acrylic emulsion and stir until well mixed to obtain mixture II;

[0078] S4. Simultaneously mix the flame retardant, mixture I, and mixture II from steps S1, S2, and S3, and add 5.5 parts of carbon black N754. Slowly add 7 parts of dodecyl alcohol ester under stirring conditions, and continuously stir at low speed until uniform. Then filter to obtain a rapid-forming and quick-setting inorganic spraying material.

[0079] Example 3

[0080] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0081] (1) Weighing:

[0082] Weigh the following raw materials according to the following weight proportions: 38 parts alkaline silica sol, 20 parts water-based acrylic emulsion, 8 parts dodecyl alcohol ester, 5 parts fatty alcohol polyoxyethylene ether, 1.8 parts polyvinyl alcohol, 1.8 parts water glass, 1 part trioctyl phosphate, 1.4 parts sodium alkyl sulfonate, 45 parts carbon black N75, 8 parts flame retardant, and 10 parts water. Set aside.

[0083] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:2:1.

[0084] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0085] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0086] S2. Add 10 parts of water to a container, and then add 5 parts of fatty alcohol polyoxyethylene ether, 1.8 parts of water glass, 1 part of trioctyl phosphate, 1.4 parts of sodium alkyl sulfonate, and 38 parts of alkaline silica sol. Stir well to obtain mixture I.

[0087] S3. Add 1.8 parts of thickener to 20 parts of water-based acrylic emulsion and stir until evenly mixed to obtain mixture II;

[0088] S4. Simultaneously mix the flame retardants from steps S1, S2, and S3, mixture I, and mixture II, and add 5 parts of carbon black N754. Slowly add 8 parts of dodecyl alcohol ester under stirring conditions, and continuously stir at low speed until uniform. Then filter to obtain a fast-forming and quick-setting inorganic spraying material.

[0089] Example 4

[0090] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0091] (1) Weighing:

[0092] Weigh the following raw materials according to the following weight proportions: 50 parts alkaline silica sol, 35 parts water-based acrylic emulsion, 10 parts dodecyl alcohol ester, 3 parts fatty alcohol polyoxyethylene ether, 1.5 parts polyvinyl alcohol, 1 part water glass, 3 parts trioctyl phosphate, 1.5 parts sodium alkyl sulfonate, 2.5 parts carbon black N754, 15 parts flame retardant, and 20 parts water. Set aside.

[0093] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:2.5:1.5.

[0094] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0095] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0096] S2. Add 20 parts of water to a container, and then add 3 parts of fatty alcohol polyoxyethylene ether, 1 part of water glass, 3 parts of trioctyl phosphate, 1.5 parts of sodium alkyl sulfonate, and then add 50 parts of alkaline silica sol. Stir well to obtain mixture I.

[0097] S3. Add 1.5 parts of thickener to 35 parts of water-based acrylic emulsion and stir until evenly mixed to obtain mixture II;

[0098] S4. Simultaneously mix the flame retardant, mixture I, and mixture II from steps S1, S2, and S3, and add 2.5 parts of carbon black N754. Slowly add 10 parts of dodecyl alcohol ester under stirring conditions, and continuously stir at low speed until uniform. Then filter to obtain a rapid-forming and quick-setting inorganic spraying material.

[0099] Example 5

[0100] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0101] (1) Weighing:

[0102] Weigh the raw materials according to the following weight proportions: 30 parts alkaline silica sol, 25 parts water-based acrylic emulsion, 4 parts dodecyl alcohol ester, 6 parts fatty alcohol polyoxyethylene ether, 1 part polyvinyl alcohol, 3 parts water glass, 2 parts trioctyl phosphate, 6.5 parts carbon black N754, 13 parts flame retardant, and 20 parts water, and set aside.

[0103] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:3:2.

[0104] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0105] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0106] S2. Add 20 parts of water to a container, and then add 6 parts of fatty alcohol polyoxyethylene ether, 3 parts of water glass, 2 parts of trioctyl phosphate, and 30 parts of alkaline silica sol in sequence. Stir well to obtain mixture I.

[0107] S3. Add 1 part of thickener to 25 parts of water-based acrylic emulsion and stir until well mixed to obtain mixture II;

[0108] S4. Simultaneously mix the flame retardant, mixture I, and mixture II from steps S1, S2, and S3, and add 6.5 parts of carbon black N754. Slowly add 4 parts of dodecyl alcohol ester under stirring conditions, and continuously stir at low speed until uniform. Then filter to obtain a rapid-forming and quick-setting inorganic spraying material.

[0109] Example 6

[0110] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0111] (1) Weighing: Weigh the raw materials according to the following weight proportions: 40 parts of alkaline silica sol, 15 parts of water-based acrylic emulsion, and 8 parts of flame retardant, and set aside.

[0112] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:2:1.

[0113] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0114] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0115] S2. Simultaneously mix the flame retardant, alkaline silica sol, and water-based acrylic emulsion, stir continuously at low speed until uniform, and then filter to obtain a rapid-forming and quick-setting inorganic spraying material.

[0116] Example 7

[0117] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0118] (1) Weighing: Weigh the raw materials according to the following weight proportions: 50 parts of alkaline silica sol, 35 parts of water-based acrylic emulsion, and 15 parts of flame retardant, and set aside.

[0119] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:3:2.

[0120] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0121] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0122] S2. Simultaneously mix the flame retardant, alkaline silica sol, and water-based acrylic emulsion, stir continuously at low speed until uniform, and then filter to obtain a rapid-forming and quick-setting inorganic spraying material.

[0123] Example 8

[0124] A method for preparing rapid-forming, quick-setting inorganic spraying materials includes the following steps:

[0125] (1) Weighing: Weigh the raw materials according to the following weight proportions: 30 parts of alkaline silica sol, 15 parts of water-based acrylic emulsion, and 8 parts of flame retardant, and set aside.

[0126] The flame retardant consists of magnesium hydroxide, aluminum hydroxide, ultrafine microcapsule-encapsulated red phosphorus FR-85, and potassium oleate, with a mass ratio of 1:1:2.5:1.5.

[0127] (2) Preparation of rapid-forming and quick-setting inorganic spraying materials:

[0128] S1. Mix magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-coated red phosphorus FR-85 evenly, and then mix with potassium oleate to obtain a flame retardant;

[0129] S2. Simultaneously mix the flame retardant, alkaline silica sol, and water-based acrylic emulsion, stir continuously at low speed until uniform, and then filter to obtain a rapid-forming and quick-setting inorganic spraying material.

[0130] The rapid-forming, quick-setting inorganic spraying material of Example 1 is used for the final mesh covering and partitioning of easily flammable working surfaces, such as... Figures 1-3 As shown, the usage method is as follows: For thin coal seams with a thickness of 1.25-1.35m and an average mining height of 1.7m:

[0131] (1) When the working face is 7m away from the stop line, start laying the metal mesh. Use Φ16×1800mm left-handed strong anchor bolts without longitudinal reinforcement to press the metal mesh. The anchor bolt spacing is 1000mm. At the same time, start laying the first steel wire rope from the transport road to the material road at the bottom of the metal mesh. After 1500mm, lay the second steel wire rope. The remaining row spacing is 600mm. The steel wire rope is Φ15mm. The steel wire ropes fix the adjacent metal meshes together. The beginning of the steel wire rope overlap is fixed to the reinforced anchor cable of the roadway shoulder with a 1m overlap length. A total of 10 steel wire ropes are used.

[0132] (2) During the mesh laying process at the working face, a rapid-forming and quick-setting inorganic spraying material is sprayed on the top surface of the single-layer metal mesh from the tail frame to the head frame of the working face. First, a layer is sprayed on the top surface of the metal mesh with a thickness of 4mm to create a relatively isolated state between the working face and the goaf. The metal mesh located behind the support frame is buried into the goaf for no less than 500mm and buried a certain distance into the goaf to play a fixing role. The upper side is pressed into the rock strata above the coal seam for no less than 500mm to play a fixing role.

[0133] (3) During the forward movement of the support, the rear part of the support and the bottom surface of the single-layer metal mesh are sprayed with a fast-forming and quick-setting inorganic spraying material with a spraying thickness of 4mm to form a membrane-covered isolation mining mesh with metal mesh as the skeleton and fast-forming and quick-setting inorganic spraying material as the film. The membrane-covered isolation mining mesh is used to completely enclose the entire working face during the mesh laying stage. Then, the end of the steel wire rope is fixed to the roadway shoulder socket reinforcing anchor cable with a coin-shaped clip, and then the support is withdrawn from the working face.

[0134] (4) The working face must be closed and mining stopped in strict accordance with the quality standard of “three straight and one flat”, namely, the coal wall is straight, the hydraulic support is straight, the conveyor is straight, and the roof and floor are flat.

[0135] The rapid-forming and quick-setting inorganic spraying material of Example 2 is used to cover and separate the non-flammable working surface after the mesh is laid. Figures 1-3 As shown, the usage method is as follows: For medium-thick coal seams with a thickness of 2.6-3m and an average mining height of 2.8m:

[0136] (1) When the working face is 12.8m away from the stop line, start laying the metal mesh. Use Φ20×2300mm left-handed strong anchor bolts without longitudinal reinforcement to press the metal mesh, with a bolt spacing of 1500mm. At the same time, start laying the first steel wire rope from the transport road to the material road at the bottom of the metal mesh. After 2000mm, lay the second steel wire rope. The remaining spacing is 800mm. The steel wire rope is Φ18.5mm. The steel wire ropes fix the adjacent metal meshes together. The beginning of the steel wire rope overlap is fixed to the reinforced anchor cable of the roadway shoulder with a tumbler clip. The overlap length is not less than 1m, and there are a total of 15 steel wire ropes.

[0137] (2) During the mesh laying process at the working face, a rapid-forming and quick-setting inorganic spraying material is sprayed on the top surface of the single-layer metal mesh from the tail frame to the head frame of the working face. First, a layer is sprayed on the top surface of the metal mesh with a thickness of 6mm to create a relatively isolated state between the working face and the goaf. The metal mesh located behind the support frame is buried into the goaf for no less than 500mm and buried a certain distance into the goaf to play a fixing role. The upper side is pressed into the rock strata above the coal seam for no less than 500mm to play a fixing role.

[0138] (3) During the forward movement of the hydraulic support, the rear part of the hydraulic support and the bottom surface of the single-layer metal mesh are sprayed with a fast-forming and quick-setting inorganic spraying material with a spraying thickness of 6mm to form a membrane-covered isolation mining mesh with metal mesh as the skeleton and fast-forming and quick-setting inorganic spraying material as the film. The membrane-covered isolation mining mesh is used to completely enclose the entire working face during the mesh laying stage. Then, the end of the steel wire rope is fixed to the roadway shoulder socket reinforcing anchor cable with a coin-shaped clip, and then the support is withdrawn from the working face.

[0139] (4) The working face must be closed and mining stopped in strict accordance with the quality standard of “three straight and one flat”, namely, the coal wall is straight, the hydraulic support is straight, the conveyor is straight, and the roof and floor are flat.

[0140] The rapid-forming, quick-setting inorganic spraying material of Example 3 is used for the final mesh covering and partitioning of easily flammable working surfaces, such as... Figures 1-3 As shown, the usage method is as follows: For thick coal seams with a thickness of 3.5-5.1m and an average mining height of 3.8m:

[0141] (1) When the working face is 15m away from the stop line, start laying the metal mesh. Use Φ22×2400mm left-handed strong anchor bolts without longitudinal reinforcement to press the metal mesh. The anchor bolt spacing is 1800mm. At the same time, start laying the first steel wire rope from the transport road to the material road at the bottom of the metal mesh. 2200mm later, lay the second steel wire rope. The remaining row spacing is 900mm. The steel wire rope is Φ20mm. The steel wire ropes fix the adjacent metal meshes together. The beginning of the steel wire rope overlap is fixed to the reinforced anchor cable of the roadway shoulder with a tumbler clip. The overlap length is not less than 1m. There are a total of 20 steel wire ropes.

[0142] (2) During the mesh laying process at the working face, a rapid-forming and quick-setting inorganic spraying material is sprayed on the top surface of the single-layer metal mesh from the tail frame to the head frame of the working face. First, a layer is sprayed on the top surface of the metal mesh with a thickness of 8mm to create a relatively isolated state between the working face and the goaf. The metal mesh located behind the support frame is buried into the goaf for no less than 500mm and buried a certain distance into the goaf to play a fixing role. The upper side is pressed into the rock strata above the coal seam for no less than 500mm to play a fixing role.

[0143] (3) During the forward movement of the hydraulic support, the rear part of the hydraulic support and the bottom surface of the single-layer metal mesh are sprayed with a fast-forming and quick-setting inorganic spraying material with a spraying thickness of 8mm to form a membrane-covered isolation mining mesh with metal mesh as the skeleton and fast-forming and quick-setting inorganic spraying material as the film. The membrane-covered isolation mining mesh is used to completely enclose the entire working face during the mesh laying stage. Then, the end of the steel wire rope is fixed to the roadway shoulder socket reinforcing anchor cable with a coin-shaped clip, and then the support is withdrawn from the working face.

[0144] (4) The working face must be closed and mining stopped in strict accordance with the quality standard of “three straight and one flat”, namely, the coal wall is straight, the hydraulic support is straight, the conveyor is straight, and the roof and floor are flat.

[0145] Table 1. Performance Comparison of Rapid Prototyping and Quick-Setting Inorganic Spraying Materials in Examples 1-3

[0146]

[0147] As can be seen from the flame retardant performance in Table 1, the flame retardant rating reaches B1, which means it is difficult to ignite and has a strong flame retardant effect. It extinguishes immediately after being removed from the fire source. As can be seen from the gas permeability, the permeability is 0, indicating good airtightness.

[0148] The gelation time in the table is less than 6 seconds, indicating that the material has the characteristic of rapid gelation. The heat resistance indicates that the material is resistant to high temperature. The aging performance indicates that the material is resistant to aging. The bonding performance indicates that the material has good bonding and good structure. The gas permeability indicates that the material has good airtightness. The flame retardant performance indicates that the material has good flame retardancy. The antistatic property indicates that the material is not static. The spraying thickness corresponds to each embodiment and is the thickness that should be sprayed on coal seams of each thickness.

[0149] The rapid-forming and quick-setting inorganic spraying material prepared by this invention has good flame retardancy and air tightness. It can form a complete enclosure of the entire working face during the mesh laying stage, and form an integral whole with the airtight walls located in the two roadways to block air leakage, thereby ensuring good isolation between the goaf and the coal mining face in the final mining stage.

[0150] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A rapid-forming, quick-setting inorganic spraying material, characterized in that, The raw materials include the following parts by weight: 30-50 parts silica sol, 15-35 parts water-based acrylic emulsion, and 8-15 parts flame retardant; The silica sol is an alkaline silica sol; The aqueous acrylic emulsion is selected from one or a mixture of several of the following: water-emulsion acrylic resin, water-dispersible acrylic resin, and water-soluble acrylic resin. The flame retardant is composed of magnesium hydroxide, aluminum hydroxide, ultrafine encapsulated red phosphorus FR-85, and potassium oleate in a mass ratio of 1:1:2-3:1-2. Magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-encapsulated red phosphorus FR-85 are mixed evenly and then mixed with potassium oleate to prepare a flame retardant. A rapid-forming and quick-setting inorganic spraying material is obtained by uniformly mixing silica sol, water-based acrylic emulsion and flame retardant. The inorganic spraying material is used for sealing the goaf and the coal face during the final mining stage.

2. The rapid prototyping and quick-setting inorganic spraying material according to claim 1, characterized in that, It also includes the following raw materials in parts by weight: 4-10 parts film-forming aid, 3-6 parts surfactant, 1-2 parts thickener, 1-3 parts dispersant, 1-3 parts defoamer, 0-1.5 parts antistatic agent, 2.5-6.5 parts carbon black, and 10-20 parts water.

3. The rapid prototyping and quick-setting inorganic spraying material according to claim 2, characterized in that, The film-forming aid is dodecyl alcohol ester; the surfactant is fatty alcohol polyoxyethylene ether; the thickener is polyvinyl alcohol; the dispersant is water glass; the defoamer is trioctyl phosphate; the antistatic agent is sodium alkyl sulfonate; and the carbon black is semi-reinforcing carbon black N754.

4. A method for preparing the rapid-forming, quick-setting inorganic spraying material as described in claim 3, characterized in that, Includes the following steps: Magnesium hydroxide, aluminum hydroxide, and ultrafine microcapsule-encapsulated red phosphorus FR-85 were mixed evenly and then mixed with potassium oleate to prepare a flame retardant. Water, surfactant, dispersant, defoamer, antistatic agent, and silica sol are stirred in sequence until homogeneous to obtain mixture I; The thickener was mixed with the aqueous acrylic emulsion to obtain mixture II; The flame retardant, mixture I, and mixture II are mixed, and carbon black is added. Then, a film-forming aid is added under stirring conditions. After stirring until uniform, the mixture is filtered to obtain a rapid-forming and quick-setting inorganic spraying material.

5. The application of the rapid-forming and quick-setting inorganic spraying material as described in claim 1 or 2 in the preparation of a self-igniting working surface end-film partition mesh.

6. The application according to claim 5, characterized in that, The application method is as follows: A single layer of metal mesh is obtained by fixing two adjacent metal meshes (3) with steel wire ropes; The single-layer metal mesh is laid on top of the support (4), and the beginning of the wire rope is fixed to the roadway shoulder reinforcement anchor cable. During the laying of the mesh in the working face, a rapid-forming and quick-setting inorganic spraying material is sprayed on the top surface of the single-layer metal mesh to form an upper film (1). Then the support (4) is moved and a rapid-forming and quick-setting inorganic spraying material is sprayed on the bottom surface of the single-layer metal mesh to form a lower film (2). Then a membrane partition mesh is formed with the metal mesh (3) as the skeleton and the rapid-forming and quick-setting inorganic spraying material as the film. After the entire working face is fully enclosed by the membrane partition mesh, the end of the steel wire rope is fixed to the roadway shoulder reinforcement anchor cable, and then the support (4) is removed from the working face.

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