A method and application for preparing fire prevention and extinguishing materials using solid waste

Abstract

The present invention relates to the technical fields of carbon dioxide sequestration and underground coal mine filling, and discloses a method for preparing a fire prevention and extinguishing material using solid waste and its application. The method specifically includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum. The fire prevention and extinguishing material prepared by the present invention has good fire extinguishing performance. After CO2 mineralization, the alkalinity of the fire extinguishing material can be reduced, and at the same time, the fluidity of the slurry can be significantly reduced, and the strength of the inert components can be improved. By using the method of the present invention, the resource utilization of alkaline solid waste, CO2 emission reduction, and fire prevention and extinguishing in coal mine gob areas can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical fields of carbon dioxide sequestration and underground coal mine filling, and particularly relates to a method for preparing a fire prevention and extinguishing material using solid waste and its application. Background Art

[0002] The stacking of coal-based solid waste and gob coal poses potential safety hazards to enterprises. Generally, measures to avoid risks include fire prevention and extinguishing using inert and flame retardant substances, three-phase foam fire prevention and extinguishing technology, air leakage prevention and extinguishing technology, pressure equalization fire prevention and extinguishing technology, and the prevention and control of fires using new fire prevention and extinguishing materials. Currently, in China, research on coal mine fire prevention and extinguishing technology mainly focuses on aspects such as theoretical basic research, breakthroughs in key technologies, preventing the expansion of the fire area and secondary disasters, and controlling the reasonable scope of secondary disasters.

[0003] Currently, the main fire prevention and extinguishing technology for underground gob areas is grouting technology. In this technology, inert materials such as yellow mud and fly ash are mixed with water and then pumped into the underground gob area. The slurry covers the coal seam prone to spontaneous combustion to achieve the purpose of extinguishing the fire. Since the yellow mud contained in the slurry has strong fluidity, it will flow to low-lying areas, unable to be densely stacked, and is prone to the "hooking" phenomenon, which is not conducive to the underground environment. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem that the grouting technology in the prior art contains yellow mud with strong fluidity, and to provide a method for preparing a fire prevention and extinguishing material using solid waste and its application. The raw materials used in this method do not contain yellow mud, have the ability to mineralize and fix CO2, and at the same time, the fluidity of the prepared mineralized slurry is significantly reduced, which can solve problems such as the resource utilization of alkaline solid waste, CO2 emission reduction, and fire prevention and extinguishing in coal mine gob areas.

[0005] To achieve the above purpose, on the one hand, the present invention provides a method for preparing a fire prevention and extinguishing material using solid waste, which includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum.

[0006] Preferably, the dosage ratio of the solid waste to water is 1 kg: 5 - 20 L, preferably 1 kg: 8 - 15 L.

[0007] Preferably, in the solid waste, the weight ratio of the main material to the additive is 1: 0.2 - 1.5, preferably 1: 0.5 - 1.1.

[0008] Preferably, the fly ash contains CaO, MgO, SiO2, Al2O3, and Fe2O3.

[0009] Further preferably, the content of CaO is 1.35 to 17.55% by weight, the content of MgO is 1.31 to 10.63% by weight, the content of SiO2 is 1.33 to 65.56% by weight, the content of Al2O3 is 1.53 to 41.32% by weight, and the content of Fe2O3 is 1.50 to 6.22% by weight.

[0010] Preferably, the carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3 and C.

[0011] Further preferably, the content of CaO is 62.13 to 69.33% by weight, the content of MgO is 1.27 to 2.56% by weight, the content of SiO2 is 5.19 to 7.92% by weight, the content of Al2O3 is 0.53 to 1.67% by weight, the content of Fe2O3 is 0.52 to 1.84% by weight, and the content of C is 3.44 to 6.38% by weight.

[0012] Preferably, the coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3 and TiO2.

[0013] Preferably, the content of CaO is 0.42 to 2.32% by weight, the content of MgO is 0.44 to 2.41% by weight, the content of SiO2 is 52 to 65% by weight, the content of Al2O3 is 16 to 36% by weight, the content of Fe2O3 is 2.28 to 14.63% by weight, and the content of TiO2 is 0.9 to 4% by weight.

[0014] Preferably, the solid waste contains fly ash, carbide slag, coal gangue and desulfurized gypsum.

[0015] Preferably, the weight ratio of the fly ash, carbide slag, coal gangue powder and desulfurized gypsum is 1:(0.3 to 1.8):(0.3 to 1.5):(0.2 to 1), preferably 1:(0.6 to 1.5):(0.5 to 1.2):(0.4 to 0.7).

[0016] Preferably, the solid waste is in powder form.

[0017] Further preferably, the particle size of the solid waste is 2 to 140 μm, the average particle size is 30 to 60 μm, and the proportion of particles smaller than 20 μm is ≥80%.

[0018] Preferably, the dosage ratio of the solid waste to CO2 is 1 kg:0.03 to 0.3 L.

[0019] Preferably, the reaction conditions include: temperature is 15 to 45 °C, and time is 20 to 40 min.

[0020] In the second aspect of the present invention, a fire prevention and extinguishing material prepared by the method described above is provided.

[0021] In the third aspect of the present invention, the application of the fire prevention and extinguishing material described above in fire prevention and extinguishing in the goaf underground is provided.

[0022] Through the above technical solutions, the beneficial effects of the present invention mainly lie in: by improving the process and raw material formula, using fly ash and carbide slag as the main raw materials, and adding coal gangue and desulfurized gypsum as additives at the same time, this additive can further improve the fire extinguishing performance. The fire prevention and extinguishing material prepared by the present invention has good fire extinguishing performance. After the CO2 is mineralized, it can reduce the alkalinity of the fire extinguishing material, and at the same time can significantly reduce the fluidity of the slurry and improve the strength of the inert components. By using the method described in the present invention, the resource utilization of alkaline solid waste, CO2 emission reduction and the effect of preventing and extinguishing fires in the goaf of coal mines can be achieved. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of a system for preparing a fire prevention and extinguishing material using solid waste according to the present invention.

[0024] Description of the Reference Numerals

[0025] 1 CO2 analyzer 2 feed hopper

[0026] 3 reaction tank 4 CO2 gas cylinder

[0027] 5 goaf underground 6 flow meter

[0028] 7 slurry pump 8 stirring paddle Detailed Embodiments

[0029] The following will describe in detail the specific embodiments of the present invention with reference to the drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0030] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0031] The first aspect of the present invention provides a method for preparing a fire prevention and extinguishing material using solid waste, which includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum, which can further improve the fire extinguishing performance.

[0032] In the method of the present invention, in a specific embodiment, the main material, the additive and water are mixed, and then CO2 is introduced into the obtained mixture for reaction, thereby preparing a mineralized slurry. The prepared fire prevention and extinguishing material has good fire extinguishing performance and can significantly reduce the fluidity of the slurry.

[0033] In the method of the present invention, in a specific embodiment, the dosage ratio of the solid waste to water can be 1 kg: 5 - 20 L, preferably 1 kg: 8 - 15 L.

[0034] In the method of the present invention, in a specific embodiment, in the solid waste, the weight ratio of the main material to the additive is 1: 0.2 - 1.5, preferably 1: 0.5 - 1.1.

[0035] In the present invention, in a specific embodiment, the fly ash contains CaO, MgO, SiO2, Al2O3 and Fe2O3.

[0036] In a preferred embodiment, the content of CaO is 1.35 - 17.55 wt%, the content of MgO is 1.31 - 10.63 wt%, the content of SiO2 is 1.33 - 65.56 wt%, the content of Al2O3 is 1.53 - 41.32 wt%, and the content of Fe2O3 is 1.50 - 6.22 wt%.

[0037] In the method of the present invention, the carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3 and C.

[0038] In a preferred embodiment, the content of CaO is 62.13 - 69.33 wt%, the content of MgO is 1.27 - 2.56 wt%, the content of SiO2 is 5.19 - 7.92 wt%, the content of Al2O3 is 0.53 - 1.67 wt%, the content of Fe2O3 is 0.52 - 1.84 wt%, and the content of C is 3.44 - 6.38 wt%.

[0039] In the present invention, in a specific embodiment, the coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3 and TiO2.

[0040] In a preferred embodiment, the content of CaO is 0.42 - 2.32% by weight, the content of MgO is 0.44 - 2.41% by weight, the content of SiO2 is 52 - 65% by weight, the content of Al2O3 is 16 - 36% by weight, the content of Fe2O3 is 2.28 - 14.63% by weight, and the content of TiO2 is 0.9 - 4% by weight.

[0041] In the method of the present invention, in a preferred embodiment, the solid waste contains fly ash, carbide slag, coal gangue, and desulfurized gypsum. Containing these four raw materials simultaneously has good fire extinguishing performance.

[0042] In the method of the present invention, in a preferred embodiment, the weight ratio of fly ash, carbide slag, coal gangue powder, and desulfurized gypsum is 1:(0.3 - 1.8):(0.3 - 1.5):(0.2 - 1), preferably 1:(0.6 - 1.5):(0.5 - 1.2):(0.4 - 0.7).

[0043] In the method of the present invention, preferably, the solid waste is in powder form. In a specific embodiment, the particle size of the solid waste is 2 - 140 μm, the average particle size is 30 - 60 μm, and the proportion of particles less than 20 μm is ≥80%.

[0044] In the method of the present invention, in a specific embodiment, the dosage ratio of the solid waste to CO2 is 1 kg: 0.03 - 0.3 L.

[0045] In the method of the present invention, in a specific embodiment, the reaction conditions include: the temperature is 15 - 45 °C, and the time is 20 - 40 min.

[0046] According to the first embodiment of the present invention, the method for preparing a fire prevention and extinguishing material using solid waste of the present invention includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and carbide slag, and the additive contains coal gangue or desulfurized gypsum.

[0047] According to the second embodiment of the present invention, the method for preparing a fire prevention and extinguishing material using solid waste of the present invention includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum; the dosage ratio of the solid waste to water is 1 kg: 5 - 20 L; in the solid waste, the weight ratio of the main material to the additive is 1:0.2 - 1.5.

[0048] According to the third embodiment of the present invention, the method for preparing a fire prevention and extinguishing material using solid waste includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum; the dosage ratio of the solid waste to water is 1 kg: 5 - 20 L; in the solid waste, the weight ratio of the main material to the additive is 1: 0.2 - 1.5; the fly ash contains CaO, MgO, SiO2, Al2O3, and Fe2O3; the content of CaO is 1.35 - 17.55%, the content of MgO is 1.31 - 10.63%, the content of SiO2 is 1.33 - 65.56%, the content of Al2O3 is 1.53 - 41.32%, and the content of Fe2O3 is 1.50 - 6.22%; the carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3, and C; the content of CaO is 62.13 - 69.33%, the content of MgO is 1.27 - 2.56%, the content of SiO2 is 5.19 - 7.92%, the content of Al2O3 is 0.53 - 1.67%, the content of Fe2O3 is 0.52 - 1.84%, and the content of C is 3.44 - 6.38%; the coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3, and TiO2; the content of CaO is 0.42 - 2.32%, the content of MgO is 0.44 - 2.41%, the content of SiO2 is 52 - 65%, the content of Al2O3 is 16 - 36%, the content of Fe2O3 is 2.28 - 14.63%, and the content of TiO2 is 0.9 - 4%.

[0049] According to the fourth embodiment of the present invention, the method for preparing a fire prevention and extinguishing material using solid waste includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum; the dosage ratio of the solid waste to water is 1 kg: 5 - 20 L; in the solid waste, the weight ratio of the main material to the additive is 1: 0.2 - 1.5; the fly ash contains CaO, MgO, SiO2, Al2O3 and Fe2O3; the content of CaO is 1.35 - 17.55 wt%, the content of MgO is 1.31 - 10.63 wt%, the content of SiO2 is 1.33 - 65.56 wt%, the content of Al2O3 is 1.53 - 41.32 wt%, and the content of Fe2O3 is 1.50 - 6.22 wt%; the carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3 and C; the content of CaO is 62.13 - 69.33 wt%, the content of MgO is 1.27 - 2.56 wt%, the content of SiO2 is 5.19 - 7.92 wt%, the content of Al2O3 is 0.53 - 1.67 wt%, the content of Fe2O3 is 0.52 - 1.84 wt%, and the content of C is 3.44 - 6.38 wt%; the coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3 and TiO2; the content of CaO is 0.42 - 2.32 wt%, the content of MgO is 0.44 - 2.41 wt%, the content of SiO2 is 52 - 65 wt%, the content of Al2O3 is 16 - 36 wt%, the content of Fe2O3 is 2.28 - 14.63 wt%, and the content of TiO2 is 0.9 - 4 wt%; the solid waste contains fly ash, carbide slag, coal gangue and desulfurized gypsum; the weight ratio of fly ash, carbide slag, coal gangue powder and desulfurized gypsum is 1: (0.3 - 1.8): (0.3 - 1.5): (0.2 - 1).

[0050] According to the fifth embodiment of the present invention, the method for preparing a fire prevention and extinguishing material using solid waste includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum; the dosage ratio of the solid waste to water is 1 kg: 5 - 20 L; in the solid waste, the weight ratio of the main material to the additive is 1: 0.2 - 1.5; the fly ash contains CaO, MgO, SiO2, Al2O3 and Fe2O3; the content of CaO is 1.35 - 17.55 wt%, the content of MgO is 1.31 - 10.63 wt%, the content of SiO2 is 1.33 - 65.56 wt%, the content of Al2O3 is 1.53 - 41.32 wt%, and the content of Fe2O3 is 1.50 - 6.22 wt%; the carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3 and C; the content of CaO is 62.13 - 69.33 wt%, the content of MgO is 1.27 - 2.56 wt%, the content of SiO2 is 5.19 - 7.92 wt%, the content of Al2O3 is 0.53 - 1.67 wt%, the content of Fe2O3 is 0.52 - 1.84 wt%, and the content of C is 3.44 - 6.38 wt%; the coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3 and TiO2; the content of CaO is 0.42 - 2.32 wt%, the content of MgO is 0.44 - 2.41 wt%, the content of SiO2 is 52 - 65 wt%, the content of Al2O3 is 16 - 36 wt%, the content of Fe2O3 is 2.28 - 14.63 wt%, and the content of TiO2 is 0.9 - 4 wt%; the solid waste contains fly ash, carbide slag, coal gangue and desulfurized gypsum; the weight ratio of fly ash, carbide slag, coal gangue powder and desulfurized gypsum is 1: (0.3 - 1.8): (0.3 - 1.5): (0.2 - 1); the solid waste is in powder form; the average particle size of the solid waste is 2 - 140 μm, and the proportion of particles less than 20 μm is ≥ 80%; the dosage ratio of the solid waste to the CO2 is 1 kg: 0.03 - 0.3 L.

[0051] According to the sixth embodiment of the present invention, the method for preparing a fire prevention and extinguishing material using solid waste includes: mixing the solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; wherein, the solid waste contains a main material and an additive, the main material contains fly ash and / or carbide slag, and the additive contains coal gangue and / or desulfurized gypsum; the dosage ratio of the solid waste to water is 1 kg: 5 - 20 L; in the solid waste, the weight ratio of the main material to the additive is 1: 0.2 - 1.5; the fly ash contains CaO, MgO, SiO2, Al2O3 and Fe2O3; the content of CaO is 1.35 - 17.55 wt%, the content of MgO is 1.31 - 10.63 wt%, the content of SiO2 is 1.33 - 65.56 wt%, the content of Al2O3 is 1.53 - 41.32 wt%, and the content of Fe2O3 is 1.50 - 6.22 wt%; the carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3 and C; the content of CaO is 62.13 - 69.33 wt%, the content of MgO is 1.27 - 2.56 wt%, the content of SiO2 is 5.19 - 7.92 wt%, the content of Al2O3 is 0.53 - 1.67 wt%, the content of Fe2O3 is 0.52 - 1.84 wt%, and the content of C is 3.44 - 6.38 wt%; the coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3 and TiO2; the content of CaO is 0.42 - 2.32 wt%, the content of MgO is 0.44 - 2.41 wt%, the content of SiO2 is 52 - 65 wt%, the content of Al2O3 is 16 - 36 wt%, the content of Fe2O3 is 2.28 - 14.63 wt%, and the content of TiO2 is 0.9 - 4 wt%; the solid waste contains fly ash, carbide slag, coal gangue and desulfurized gypsum; the weight ratio of fly ash, carbide slag, coal gangue powder and desulfurized gypsum is 1: (0.3 - 1.8): (0.3 - 1.5): (0.2 - 1); the solid waste is in powder form; the average particle size of the solid waste is 2 - 140 μm, and the proportion of those less than 20 μm is ≥ 80%; the dosage ratio of the solid waste to the CO2 is 1 kg: 0.03 - 0.3 L; the reaction conditions include: the temperature is 15 - 45 °C, and the time is 20 - 40 min.

[0052] The second aspect of the present invention provides a fire prevention and extinguishing material prepared by the method described above. This fire prevention and extinguishing material has good fire extinguishing performance. After CO2 mineralization, it can reduce the alkalinity of the fire extinguishing material, and at the same time can significantly reduce the fluidity of the slurry, improve the strength of inert components, and achieve the resource utilization of alkaline solid waste, CO2 emission reduction and the effect of preventing and extinguishing fires in goafs of coal mines.

[0053] In the third aspect of the present invention, there is provided the application of the fire prevention and extinguishing material described above in fire prevention and extinguishing in the goaf underground.

[0054] In the present invention, the prepared fire prevention and extinguishing material is transported to the goaf underground and covered on the surface of the residual coal that needs fire prevention and extinguishing treatment, isolating oxygen so that the residual coal cannot reach the spontaneous combustion condition. After the moisture penetrates and dries out, it will form a dense inert ash layer, thus achieving the purpose of fire prevention and extinguishing.

[0055] The present invention also provides a system for preparing a fire prevention and extinguishing material using solid waste. This system is used to implement the method described above. As Figure 1 shown, it includes a reaction tank 3, a CO2 gas cylinder 4, and a CO2 analyzer 1. The feeding hopper 2 is used to add solid waste and water into the reaction tank 3. The CO2 gas cylinder 4 is used to input CO2 into the reaction tank 3. The CO2 analyzer 1 is used to analyze the concentration of CO2 in the reaction tank 3. Preferably, when the remaining CO2 concentration in the reaction tank 3 accounts for 10 - 20% of the input amount of CO2, the reaction is terminated.

[0056] A stirring paddle 8 is arranged in the reaction tank 3. When the solid waste, water, and CO2 react in the reaction tank 3, the stirring paddle 8 generates negative pressure under high-speed rotation, and CO2 is sucked into the stirring impeller and can be fully sheared and dispersed into the solution, quickly undergoing a mineralization reaction to form carbonate precipitation. In the specific implementation manner, the stirring conditions of the stirring paddle 8 include: the rotation speed is 1500 - 2500 rpm, and the time is 3 - 8 min.

[0057] In a preferred implementation manner, the system further includes a temperature controller for controlling the temperature in the reaction tank 3.

[0058] In a preferred implementation manner, the system further includes a flow meter 6 for measuring the flow rate of CO2 introduced from the CO2 gas cylinder 4 into the reaction tank 3.

[0059] In the present invention, the system further includes a goaf 5 underground. A slurry pump 7 is arranged between the reaction tank 3 and the goaf 5 underground. The mineralized slurry prepared in the reaction tank 3 is pumped into the goaf 5 underground through the slurry pump 7. The mineralized slurry is covered on the surface of the residual coal that needs fire prevention and extinguishing treatment, isolating oxygen so that the residual coal cannot reach the spontaneous combustion condition. After the moisture penetrates and dries out, it will form a dense inert ash layer, thus achieving the purpose of fire prevention and extinguishing.

[0060] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0061] The following examples and comparative examples are all carried out in Figure 1It is implemented in the system for preparing fire prevention and extinguishing materials using solid waste. The system includes a reaction tank 3, a CO2 gas cylinder 4, and a CO2 analyzer 1. The feeding hopper 2 is used to add solid waste and water into the reaction tank 3. The CO2 gas cylinder 4 is used to input CO2 into the reaction tank 3. The CO2 analyzer 1 is used to analyze the concentration of CO2 in the reaction tank 3. A stirring paddle 8 is arranged in the reaction tank 3. The system also includes a temperature controller for controlling the temperature in the reaction tank 3. The system also includes a flow meter 6 for measuring the flow rate of CO2 introduced from the CO2 gas cylinder 4 into the reaction tank 3. The system also includes an underground goaf 5. A slurry pump 7 is arranged between the reaction tank 3 and the underground goaf 5. The mineralized slurry prepared in the reaction tank 3 is pumped into the underground goaf 5 through the slurry pump 7.

[0062] In all embodiments of the present invention, the contents of each component in fly ash, carbide slag, and coal gangue in the solid waste are the same. The contents of each component in fly ash, carbide slag, and coal gangue in the solid waste are shown in Table 1.

[0063] Table 1 Contents of each component in fly ash

[0064] Component CaO MgO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> Content (wt%) 15 9 40 30 6

[0065] Contents of each component in carbide slag

[0066] Component CaO MgO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> C Content (wt%) 67 2.5 7.5 1.5 1.5 6

[0067] Contents of each component in coal gangue

[0068] Component CaO MgO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[TiO2]]> Content (wt%) 2 2 60 22 12 2

[0069] Example 1

[0070] Transport 35 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 28 kg of carbide slag, 20 kg of coal gangue powder, 17 kg of desulfurized gypsum, and 1000 L of industrial water to the feeding hopper 2, and then enter the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then introduce 20 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after CO2 dissolves, it undergoes a mineralization reaction with alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1. During the reaction process, control the temperature through the temperature controller (the temperature is 30 °C). Observe the outlet CO2 concentration transmitted by the CO2 analyzer 1. Terminate the reaction when the concentration reaches 15% of the CO2 introduction amount. Then turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and wait for it to flow and solidify by itself to complete the entire process of preparing fire prevention and extinguishing materials by CO2 mineralizing solid waste.

[0071] Example 2

[0072] Transport 30 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 25 kg of carbide slag, 25 kg of coal gangue powder, 20 kg of desulfurized gypsum, and 1000 L of industrial water to the hopper 2, and then enter the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 16 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1, control the temperature during the reaction (the temperature is 25 °C) through the thermostat, observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 introduction amount. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the process of preparing the fire prevention and extinguishing material by CO2 mineralizing solid waste.

[0073] Example 3

[0074] Transport 30 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 18 kg of carbide slag, 34 kg of coal gangue powder, 18 kg of desulfurized gypsum, and 1000 L of industrial water to the hopper 2, and then enter the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 13 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1, control the temperature during the reaction (the temperature is 20 °C) through the thermostat, observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 introduction amount. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the process of preparing the fire prevention and extinguishing material by CO2 mineralizing solid waste.

[0075] Example 4

[0076] Transport 30 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 45 kg of carbide slag, 25 kg of coal gangue powder, and 1000 L of industrial water to the hopper 2, and then into the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 26 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1. During the reaction process, control the temperature through the thermostat (the temperature is 20 °C), observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 input volume. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the entire process of preparing the fire prevention and extinguishing material by CO2 mineralizing solid waste.

[0077] Example 5

[0078] Transport 55 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 45 kg of coal gangue powder, and 1000 L of industrial water to the hopper 2, and then into the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 6 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1. During the reaction process, control the temperature through the thermostat (the temperature is 20 °C), observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 input volume. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the entire process of preparing the fire prevention and extinguishing material by CO2 mineralizing solid waste.

[0079] Comparative Example 1

[0080] Implement according to the method of Example 1, except that the solid waste only contains fly ash and carbide slag. The specific method is as follows:

[0081] Transport 50 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 50 kg of carbide slag, and 1000 L of industrial water to the feed hopper 2, and then enter the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 20 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1. During the reaction process, control the temperature through the thermostat (the temperature is 30 °C), observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 introduction amount. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the process of preparing the fire prevention and extinguishing material by CO2 mineralizing solid waste.

[0082] Comparative Example 2

[0083] Implement according to the method of Example 1, except that the solid waste only contains coal gangue powder and desulfurized gypsum. The specific method is as follows:

[0084] Transport 55 kg of coal gangue powder with an average particle size of 45 μm, 80% of which is less than 20 μm, 45 kg of desulfurized gypsum, and 1000 L of industrial water to the feed hopper 2, and then enter the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 20 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1. During the reaction process, control the temperature through the thermostat (the temperature is 30 °C), observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 introduction amount. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the process of preparing the fire prevention and extinguishing material by CO2 mineralizing solid waste.

[0085] Comparative Example 3

[0086] Implement according to the method of Example 1, except that the solid waste only contains fly ash and yellow mud. The specific method is as follows:

[0087] Transport 45 kg of fly ash with an average particle size of 45 μm, 80% of which is less than 20 μm, 55 kg of yellow mud, and 1000 L of industrial water to the hopper 2, and then enter the reaction tank 3. Adjust the rotation speed of the stirring paddle 8 to 2000 rpm and stir for 5 minutes. Then, introduce 20 L of CO2 from the CO2 gas cylinder 4 into the reaction tank 3 for reaction for 30 min (after the CO2 dissolves, it undergoes a mineralization reaction with the alkaline metal ions in the solution). At the same time, turn on the CO2 analyzer 1, control the temperature during the reaction (the temperature is 30 °C), observe the outlet CO2 concentration transmitted by the CO2 analyzer 1, and terminate the reaction when the concentration reaches 15% of the CO2 introduction amount. Then, turn on the slurry pump 7, inject the obtained mineralized slurry into the underground goaf 5, cover the upper space of the coal seam, and after it self-flow solidifies, complete the entire process of preparing the fire prevention and extinguishing material by CO2 mineralization of solid waste.

[0088] Test Example 1

[0089] Detect the fire extinguishing performance, fluidity, and strength of the fire prevention and extinguishing materials prepared in Test Examples 1 - 5 and Comparative Examples 1 - 3. The results are shown in Table 2.

[0090] (1) The fire extinguishing performance of the fire prevention and extinguishing material is represented by the fire prevention critical oxygen concentration. The critical oxygen concentration is detected using a critical oxygen tester, and its principle is the vertical burning method. The method is as follows: Place a 150 mm × 58 mm fire prevention and extinguishing material into the test device, conduct the test in the atmosphere with a temperature of 10 - 30 °C and a relative humidity of 30 - 80%, introduce a mixed gas of oxygen and nitrogen with an initial volume ratio of 1:3, ignite the fire prevention and extinguishing material with an igniter, and measure the fire prevention critical oxygen concentration. The higher the critical oxygen concentration, the higher the oxygen concentration required for combustion, the more demanding the combustion conditions, and the better the fire prevention and extinguishing performance.

[0091] (2) The fluidity of the fire prevention and extinguishing material is represented by the consistency value (penetration). A mortar consistency tester is used to detect the consistency value of the fire prevention and extinguishing material. The larger the consistency value, the stronger the fluidity.

[0092] (3) The strength of the fire prevention and extinguishing material is represented by the compressive strength. A compressive testing machine is used to detect the compressive strength of the fire prevention and extinguishing material. Its principle is to use the compressive testing machine to increase the load to break the specimen, and the pressure at the time of breakage is the compressive strength.

[0093] Table 2

[0094] Number Fire extinguishing performance (%) Flowability (mm) Strength (MPa) Example 1 32 19 2.3 Example 2 30 21 2.1 Example 3 31 22 2.1 Example 4 29 27 1.9 Example 5 28 28 1.8 Comparative Example 1 26 39 1.7 Comparative Example 2 27 38 1.6 Comparative Example 3 26 45 1.6

[0095] From the results in Table 2, it can be seen that the fire prevention and extinguishing material prepared by the method of the present invention has good fire extinguishing performance.

[0096] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing fire prevention and extinguishing materials using solid waste, characterized in that, The method includes: mixing solid waste with water, and then introducing CO2 into the obtained mixture for reaction to obtain a mineralized slurry; Wherein, the solid waste is composed of a main material and an additive. The main material is fly ash and carbide slag, and the additive is coal gangue and desulfurized gypsum. The weight ratio of the fly ash, the carbide slag, the coal gangue, and the desulfurized gypsum is 1:(0.6 - 1.5):(0.5 - 1.2):(0.4 - 0.7).

2. The method according to claim 1, characterized in that, The dosage ratio of the solid waste to water is 1 kg:5 - 20 L.

3. The method according to claim 2, characterized in that, The dosage ratio of the solid waste to water is 1 kg:8 - 15 L.

4. The method according to any one of claims 1 to 3, characterized in that, In the solid waste, the weight ratio of the main material to the additive is 1:0.2 - 1.

5.

5. The method according to any one of claims 1-3, characterized in that In the solid waste, the weight ratio of the main material to the additive is 1:0.5 - 1.

1.

6. The method according to any one of claims 1-3, characterized in that The fly ash contains CaO, MgO, SiO2, Al2O3, and Fe2O3.

7. The method according to claim 6, characterized in that, The content of CaO is 1.35 - 17.55 wt%, the content of MgO is 1.31 - 10.63 wt%, the content of SiO2 is 1.33 - 65.56 wt%, the content of Al2O3 is 1.53 - 41.32 wt%, and the content of Fe2O3 is 1.50 - 6.22 wt%.

8. The method according to any one of claims 1-3, characterized in that, The carbide slag contains CaO, MgO, SiO2, Al2O3, Fe2O3, and C.

9. The method according to claim 8, wherein The content of CaO is 62.13 - 69.33 wt%, the content of MgO is 1.27 - 2.56 wt%, the content of SiO2 is 5.19 - 7.92 wt%, the content of Al2O3 is 0.53 - 1.67 wt%, the content of Fe2O3 is 0.52 - 1.84 wt%, and the content of C is 3.44 - 6.38 wt%.

10. The method according to any one of claims 1 to 3, characterized in that The coal gangue contains CaO, MgO, SiO2, Al2O3, Fe2O3, and TiO2.

11. The method according to claim 10, wherein The content of CaO is 0.42 - 2.32 wt%, the content of MgO is 0.44 - 2.41 wt%, the content of SiO2 is 52 - 65 wt%, the content of Al2O3 is 16 - 36 wt%, the content of Fe2O3 is 2.28 - 14.63 wt%, and the content of TiO2 is 0.9 - 4 wt%.

12. The method according to any one of claims 1-3, characterized in that The solid waste is in powder form.

13. The method according to any one of claims 1 to 3, characterized in that The particle size of the solid waste is 2 - 140 μm, the average particle size is 30 - 60 μm, and the proportion of those less than 20 μm is ≥80%.

14. The method according to any one of claims 1 to 3, characterized in that, The dosage ratio of the solid waste to the CO2 is 1 kg:0.03 - 0.3 L.

15. The method according to any one of claims 1 to 3, characterized in that, The conditions of the reaction include: the temperature is 15 - 45 °C, and the time is 20 - 40 min.

16. A fire prevention and extinguishing material prepared by the method according to any one of claims 1 - 15.

17. Application of the fire prevention and extinguishing material according to claim 16 in fire prevention and extinguishing in the goaf of an underground mine.

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