Fire prevention technology currently used at coal mines are: plugging, equalizing, inert gas, inert foam, foam-phase, stopping agent, fogging agent resistance, resistance inerting agent, fire water, grout, colloidal Fire-fighting technology, etc., these technologies can be returned to the following categories according to their main functions and functions: (1) The main purpose of controlling air leakage technology is: Reduce or eliminate the supply of loose coal oxygen. Technical means are: cement spray; foam spray; nano-modified elastomer material application; pressure equalization. The cement shotcrete has a large workload, many rebounds, poor dynamic pressure resistance, and the plugging effect is not very satisfactory; the foam plugging performance is good, the dynamic pressure resistance is good, but its cost is high, it decomposes at high temperature, and releases harmful gases; The nano-modified elastomer material has the properties of good air tightness and large elongation. It can be scraped, coated and wiped in the leakage of coal rock, wood and closed wall. It is easy to operate and easy to use. The curing time can be adjusted according to the construction needs. After curing, the surface forms an elastomer. The closed-area pressure equalization can reduce the air leakage into the enclosed area. The open-area pressure equalization can reduce the pressure difference around the goaf and reduce the leakage of coal into the goaf, thus reducing the risk of spontaneous combustion, but it has already occurred or has occurred. In the self-igniting fire zone, it is unrealistic to rely solely on the pressure equalization to completely eliminate the air leakage and prevent spontaneous combustion. (2) The main purpose of the fire zone inerting technology is: Reduce the O2 concentration in the fire zone and suffocate the fire zone. The technical means are: injection of inert gas such as N2 and CO2; inert gas foam; three-phase foam. Inert gas and foam can cover the entire space, which can quickly smother the open flame and inhibit the development of the high-temperature fire zone of coal seam spontaneous combustion. However, the cooling effect of the coal body with large heat capacity is not good, the fire extinguishing cycle is long, and the fire zone is easy to re-ignite. And the requirements for on-site plugging air are high. The inert foam and three-phase foam can play the role of nitrogen fixation, cooling, reducing air leakage, reducing oxygen concentration in the goaf, and encapsulating the coal body. However, the foam has a short stabilization time, is injected in the crushed coal, has poor foaming performance, and has a foaming multiple. Low, if it only acts as a resisting agent, the cost is too high and the efficiency is low. For the floating coal that has formed high temperature, only the inertia foam is used to extinguish the fire, and the amount of inert foam is large, and it is easy to re-ignite. (3) The main purpose of coal body resistance technology is to: Reduce the oxidation activity of coal and inhibit the coal-oxygen combination. The technical means are: injection of CaCl2, MgCl2 and other highly water-absorbing salts; atomization inhibitor; inertization inhibitor. When the aqueous solution of CaCl2 and MgCl2 adheres to the surface of the coal body, a film of aqueous liquid is formed to prevent the contact of coal and oxygen, and at the same time, the coal body can be kept in a wet state for a long time, and the temperature is not easily increased at the time of low temperature oxidation, thereby suppressing the self of coal. Heat and spontaneous combustion; the retarding agent has a good fireproof effect, but when the water in the coal evaporates and is reduced to a certain extent, the resisting action will stop, and then become a catalytic effect, promoting the oxidation and spontaneous combustion of the coal. When the coal temperature exceeds a certain temperature, the inerting inhibitor will start to absorb heat and vaporize, generate an inert gas, and block the free radical chain reaction process in the fire zone. The residue after pyrolysis is naturally coated with a film on the coal surface. After cooling, it becomes a brittle covering, which separates the coal from the air; however, the material is not easily dispersed evenly into the coal body, and the fire-fighting performance is fully exerted, and if it is injected into the coal body with its aqueous solution, it is easily lost. (4) The main purpose of the heat absorption and cooling technology is: Reduce the temperature of the high temperature coal body, completely extinguish the high temperature fire zone, and prevent the fire zone from re-igniting. Technical means are: water injection; grouting; liquid nitrogen; liquid CO2. The key to extinguishing the coal fire zone is to reduce the coal temperature. Water is the most economical and most widely used heat-absorbing and cooling material. Its heat capacity is large. When 1L of water is converted into steam, it absorbs 2256.7kJ of heat and is naturally 1.7m. Water vapor can quickly reduce the temperature of coal. A large amount of water vapor has the effect of diluting the oxygen concentration in the air, enveloping, isolating the fire source and suffocating the fire source. Grouting and fire prevention technology is widely used in mines with natural fire hazard in China. The mud can absorb heat and cool down, and has a wrapping effect on the coal body to achieve the purpose of oxygen barrier. The fire prevention effect of the goaf is obvious, and it has become one of the main measures to fight the fire in the underground. However, the self-igniting fire source in the underground is usually in a relatively high position. When it is extinguished with water or mud, it can not stay in the fire site, and it is easy to form a fixed channel activity. After flowing through the fire site, only the surface temperature of the coal is lowered, and the internal temperature of the coal body is still very high. High; the flushing of water takes away the ash on the surface of the coal body, and exposes the surface of the new coal body. The violent evaporation of water increases the porosity of the coal, making the air leakage channel more smooth; the water will decompose into H2 and O2 above 600 °C. There is a danger of water and gas explosion, posing a great threat to downhole firefighters. (5) Colloidal fire prevention technology The anti-extinguishing technology developed by Xi'an University of Science and Technology, such as gel, colloidal mud, thickened colloid and composite colloid, integrates the functions of plugging, cooling, resisting and solidifying water, so that the easy-to-active aqueous solution can be gelatinized at specified times and locations. Condensation, wrapping high-temperature coal, fully exerting the heat absorption and cooling effect of water, and better solving the problem of leakage loss of grouting and water injection. In the open fire of nearly 1000 °C, it will not vaporize rapidly, but will gradually shrink due to the slow evaporation of water. The fire safety is good. Under the environment of 90% humidity and 28 °C, it will remain intact after 13 months. At the same time, in the field use and promotion process of the technology, various application processes such as underground mobile, pipe network, ground mobile and ground fixed multi-functional grouting and anti-fire extinguishing systems have been developed, which can be based on the actual mine conditions. Conditions are flexibly designed and used. 1. Colloidal Fire Extinguishing Material Performance Colloidal fire extinguishing technology has been widely used as a new type of fire prevention technology. It has been widely used in the prevention and control of underground coal seam fires. The colloidal fire extinguishing material has the following fire extinguishing performance: (1) Solid water. More than 90% of the pure colloid is water, and the water that is easy to move is solidified to fully exert the effect of cooling the water. (2) Thermal degradation. The gelation process is an endothermic reaction, and the increase in coal temperature causes vaporization of the water in the colloid and also absorbs a large amount of heat. (3) Penetration and plugging. The gel-forming material is a liquid that is easy to move, penetrates into the gap of the coal seam to form a colloid, and blocks the air leakage passage. (4) Inhibition. The coagulant and the base material are both inhibitors. The natural materials of the two are also inhibitors. The colloid has the properties of a universal inhibitor and still has good fire-proof performance against high-sulfur ore. (5) Thermal stability. At a high temperature of 1000 ° C, the colloid does not melt, does not break, and can still remain intact, but slowly loses water and dry, but the residue (enhancer and SiO2) still fills the pores of the coal. (6) Filling performance. The amount of reinforcing agent (loess, fly ash, sand, etc.) increases, the colloidal pressure resistance is enhanced, and the high-concentration colloidal mud can fill the high-air roof area. (7) Under normal conditions (T<28°C, humidity>90%), the colloid can be stored in the coal seam for a long time (the field is still intact for 13 months) to prevent spontaneous ignition of the coal seam or re-ignition of the fire zone. (8) The glue forming time can be controlled, which is convenient for proper adjustment according to different fire conditions and on-site use process. The shortest gel forming time is 25s, and the slow glue can be controlled for 10h. The gel forming speed is adjusted according to the fire zone conditions and the conveying interval and the drilling penetration range. (9) The materials are widely available, the cost is low, and the process is simple. The large-flow injection-injection colloidal mud process compatible with the grouting system can be used to extinguish large-area coal seam spontaneous combustion fires. Preform Mould,Cap Mold,PP Blowing Mold,Preform Mold Demark(changxing)injection system CO. LTD , https://www.petplas.com