Application of colloidal fire prevention technology in fully mechanized caving mining

In recent years, Yanzhou Mining (Group) Co., Ltd. and its subordinate mines have actively carried out scientific and technological research, and successfully applied various new composite colloid fire prevention technologies to underground fire prevention, effectively ensuring the safe production of mines.

1 colloidal mud quickly extinguishes coal mine fires

　　 Yanzhou Mining (Group) Company Dongtan coal mine fire extinguishing methods commonly used in the case are not effective, the use of glue mud fire extinguishing technology, successfully put out the fire zone 14308 west rail transportation lane, to protect the safety of mine production. The 14308 West Rail Shunhuo District is located in the top goaf. The fire point is the old fire point in the goaf at the top of the roadway. The amount of coal left at the fire source point is large and the re-ignition speed is very fast. The heat in the fire area is very large, and the fire is difficult. Big.

The entire fire fighting process is divided into three stages.

In the first stage, because the top of the 14308 west rail fire area is a large amount of floating coal roadway in the goaf, the fire was extinguished with water during the last fire. The top coal fell and formed many voids. The support was like a grate and the support strength was also Not high, for the anti-colloidal mud to leak into the tunnel, using multiple holes (no less than 12 holes each time), low flow (each flow rate is 1~2m3/h) injection, glue speed control Within 1min. The drilling hole is drilled from the fire extinguishing road with a flat drill or elevation angle of 3°, drilling 8m into the falling roof of the goaf, 4.8~5.2m from the west rail of 14308, and 450m3 of cement slurry is injected three times.

In the second stage, after two rounds of fire detection, no leakage was found, and it was decided to drill a hole with a depression angle of 3° and a depth of 8m. During the drilling process, only a large amount of CO was drilled in the borehole, and no smoke was seen. 3 days injection of colloidal mud 500m3.

In the third stage, the fire extinguishing of the first two stages showed that the injection of the gel was very successful in preventing leakage. However, due to poor permeability, there was no penetration into the bottom, and a colloid layer was formed in the upper part of the fire area. No water was seen at the fire source. And glue, so adjust the drilling so that the final hole position reaches 3.5~4.0m from the top of the roadway into the fire area, slow down the speed of the glue, so that the colloid enters the fire area, that is, the construction of the 10°~12° hole, the hole depth 10~12m, the verified drilling arrangement is basically in place. In the 10m range before and after the center of the fire source, the boreholes with a slope of 10°~12° were all re-arranged, and the continuous injection of colloidal mud was 900m3 for 6 days. After the fire zone unsealed successful rescue team into the reconnaissance, the fire has been extinguished, spraying the roadway and hit all the re-hanging metal complex network, spray once.

2 Comprehensive mechanized top coal caving face, gel resistance, fire prevention

Yanzhou Mining (Group) Co., Ltd. Nanxun Coal Mine used the technology of gel resistance and plugging in the high-temperature auto-ignition of the top coal in the 63 super 10 mechanized top coal caving face, successfully inhibiting the preparation and recovery period. The spontaneous combustion incident, this is the first time in the national coal system. Later, it was applied in Baodian Coal Mine and Daqiao Coal and Electricity Company Yaoqiao Coal Mine, and both achieved remarkable social and economic benefits.

Mining coal seams with a tendency to spontaneous combustion, especially the use of fully mechanized top coal caving technology along the trough, is a major problem in underground fire prevention. In the mining production, the loose roofing coal is caused by the adjacent roadway along the floor of the coal seam, and the remaining communication lanes have been blocked, but there is still a problem of air leakage. The traditional method of plugging is difficult to work. Gel resistance plugging technology

The gel retardant used is a viscoplastic compound composed of a main agent and a coagulant. After mixing the two solvents, a jelly-like colloid is formed, and the solidification time can be controlled according to the needs of the formula. Seconds to one month. In the choice of acid coagulants, they screened a dozen acid materials and found low toxicity, low cost, high performance formulations.

This material has the following characteristics:

1 permeability is good. The viscosity of the mixture before solidification is similar to that of water, which can penetrate into the cracks of coal and rock. The viscosity after gelation is 1500 times that of water, and it has the flame retardancy of general inhibitor.

2 has a sealing performance. It can prevent the underground roadway from leaking air through the broken coal body, and can bear a pressure of 3.92 kPa, thereby preventing the air leakage.

3 has solid water performance. 90% to 96% of the liquid is water, which solidifies the easily flowing water, which not only acts in the coal body, but also exerts physical properties of water to prevent coal oxidation and heat absorption and temperature drop.

4 has endothermic cooling performance. The gelation reaction is an endothermic reaction, and the heat absorption is greater than 104 kcal/m3, thereby cooling the coal body.

5 The injection process is simple and inexpensive.

6 is not easy to lose water, long life. The cost of the gel inhibition technology varies with the gelation time, which is between 40 and 80 yuan/m3.

3 Comprehensive mechanized top coal caving face composite colloid fire prevention technology

The "Compound Colloid Fire Prevention Technology" jointly researched by Xi'an Institute of Science and Technology and Zhangzhou Mining (Group) Co., Ltd. is a new fire extinguishing technology developed on the basis of gel fire prevention technology. More than 99% of the colloids are bound water, and the potential for heat absorption and cooling is greater. The amount of gelling materials is greatly reduced compared with the previous colloidal fire extinguishing technology, which reduces the transportation volume of underground fire extinguishing materials by more than 90%, and the gel performance is also improved. It provides new methods and ways for fire prevention in coal seams.

The compound colloid fire prevention technology uses a quantitative adding device to add the thickening agent to the water in a certain proportion to thicken the water or mud, and then inject it into the loose coal body by using a pump or a grouting system, and the thickening liquid acts on the pumping pressure and the self-weight. Underfiltration into the coal body cracks and tiny pores and endothermic, in order to reduce the temperature of the coal body, block the pores and cracks of the loose coal body, so that oxygen molecules can not penetrate into the coal body, greatly reducing the probability of coal oxygen contact, reducing coal The body's own oxidative exothermic properties and spontaneous combustion. The downhole portable mobile injection molding process mainly uses the XKC-5/18 composite colloid injection machine to mix and mix various colloidal materials to the fire source point, and can quickly and effectively treat the local fire zone and high temperature zone. Convenient and flexible. Sometimes the underground coal seam has a large fire range, and a large flow rate (usually 30~100m3/h) is required. The thickener, the reinforcing agent and the solvent are arranged from the ground slurry tank, and the ground grouting fire extinguishing system, the sand injection fire extinguishing system and the dustproof water pipeline system are injected into the fire source.

During the excavation of the 4308 return airway in Dongtan Coal Mine, the mining of the 4308 comprehensive mechanized caving mining face, the 14307 stop mining line and the adjacent goaf of the 5309 return airway in Baodian Coal Mine, the application shows that the composite colloidal additive When the dosage is 3‰, it has the same performance as the gel concentration of 10%; it has certain strength and permeability, creep and viscoelasticity; it has thixotropic property and the viscosity is reduced by heat; it has good heat absorption and is extinguished by fire. It does not produce a large amount of water vapor at the time; the fire resistance is quite good; it can be stored in the coal seam for a long time to prevent the coal seam from spontaneous combustion or re-ignition in the fire zone.

4 Promotion of colloidal fire prevention and extinguishment in comprehensive mechanized top coal caving face

The Jining No. 2 Coal Mine of Zhangzhou Mining (Group) Co., Ltd. used the composite colloid fire prevention technology to control the fire in the goaf in the 23 05 comprehensive mechanized top coal caving face, and achieved remarkable results. This coal mine produces more than 10,000 tons of raw coal per day. Due to the large-scale mining strength of the integrated mechanized top coal mining technology, the top coal release rate at the end of the hydraulic support is low (some do not put), and the amount of coal left in the goaf is relatively high. Along the floor and other reasons, the coal seam spontaneous combustion source of the comprehensive mechanized top coal mining face is concealed, and the fire source point is high, the oxidation heat storage cycle is long, and the temperature of the surrounding rock layer is also high when the fire sign is found. Large, the coal-fired spontaneous combustion rate increased, coal mine spontaneous combustion fire accidents increased. To this end, the mine uses a downhole portable mobile injection molding process, using a composite colloidal injection machine as a quantitative addition device, the thickener is added to the water in a certain proportion, thickening the water or mud, and then pumping or grouting

Pressed into the loose coal body, under the action of pump pressure and self-weight, the thickened liquid penetrates into the cracks and tiny pores of the coal body and absorbs heat, which lowers the temperature of the coal body and blocks the pores and cracks of the loose coal body. The oxygen molecules can not penetrate into the interior of the coal body, greatly reducing the probability of coal oxygen contact, reducing the oxidation heat release performance of the coal body itself, and reducing the self-ignitability.

Practice has proved that the process is flexible, the equipment is small, and the amount of additives is small. It can be quickly and effectively treated for local fire zones and high temperature zones. Sometimes the coal seam in the underground has a large range of fires. It requires a large-flow (usually 30-100 m3/h) injection-injection fire-extinguishing process. The thickeners, reinforcing agents and solvents are prepared from the ground slurry tank. The ground grouting fire prevention system, the sand injection fire prevention system and the dustproof water pipeline system are injected into the fire source. The return air angle of 23 under 05 fully mechanized caving face has been C2H2 concentration up to 92ppm, CO concentration 196ppm, and with the increase of CH4 content, they are ineffective in increasing grouting volume and vapor resistance method. The colloidal mud is injected into the goaf to reduce the concentration of C2H2 to 0, the concentration of CO to about 20 ppm, and the concentration of CH4 and CO2.

Application of sodium meta-aluminate in coal mine gel fire prevention

The gel fire prevention technology using ammonium bicarbonate as a coagulant has been promoted and applied in coal mines. However, the currently used gel releases a large amount of ammonia gas during the gelation process, which pollutes the air under the well and is not conducive to the health of the operator. For this purpose, Yanzhou Mining (Group) Company Dongtan coal using sodium bicarbonate as a partial substitute aluminum coagulants, ammonia is eliminated, the gel performance to the fire prevention requirements. After being applied in the fire fighting work in the underground fire area of ​​Dongtan Coal Mine, it has achieved obvious fire extinguishing effect. Later, it was applied in the fire prevention work of Xinglongzhuang Coal Mine, Nantun Coal Mine and Baodian Coal Mine in Yanzhou Mining Area. Good economic and social benefits have great promotional value.

The use of non-toxic and odorless materials as coagulant is the key to reduce or eliminate the production of ammonia. They use the water glass (Na2O?nSiO2) as the base material and sodium meta-aluminate (NaAlO2) as the accelerator. Sodium metaaluminate is a coagulant that is feasible. It is a low-cost accelerator material with high resistivity, rapid setting, cooling, non-toxic and odorless. The gelation time of the new coagulant colloid can be adjusted according to the ratio. The accelerator is selected by the stoichiometric pump. The process is simple, the ratio is accurate, and the reliability is good. The gelation process is stable in 5% to 6% water glass and 3% to 4% sodium metaaluminate, and can meet the requirements of on-site use. Therefore, under the condition that the ratio of 5% water glass is constant, the appropriate sodium metaaluminate is selected according to the actual situation. According to the results of the use of the upper and lower wells and the information provided by the Chongqing Branch of the Coal Research Institute, the colloid after gelation has the following performance indicators: water content above 90%, up to 93%; easy to flow before gel formation, after gelation It is solid colloidal, with liquid osmotic plugging function; gelation process is endothermic reaction, so it has endothermic and cooling function; colloid has resisting performance, resistivity is more than 50% at 60 °C, and resistance at 80 °C The rate is over 70%; the colloid is non-toxic and tasteless and will not affect the working environment.

6 comprehensive fire prevention technology in closed CO over-limit area application

Yancun Mining (Group) Co., Ltd. Yangcun Coal Mine applied comprehensive fire prevention technology in the CO overrun area of ​​the 305 stop-line mining goaf, successfully eliminating CO overrun and preventing fire spread. When they analyzed the beam tube, they found that the CO concentration in the goaf was abnormal. The Department of General Defense and the Tongfang Work Area immediately investigated and took reconsideration measures, which responded quickly and conformed to the guiding ideology of eliminating the accident in the bud. After adopting the military ventilation and sealing the air leakage passage, the method of drilling and injecting the glue from the 305 contact lane to the 305 goaf is used to inject the rubber into the high temperature point and to 305

The treatment method of sealing the air leakage passage by the injection body at the end of the track and the stop of the belt. According to the progress of drilling construction, drilling and glue injection and 305

The method of intersecting the groove in the track and the belt in the end of the belt is stopped. The colloidal materials are baking soda (sodium bicarbonate), water glass and yellow mud. The ratio (mass ratio) is yellow mud: water glass: sodium hydrogencarbonate = 21:3:1. The gelation time is 60 to 100 s. The ground grouting system is used to prepare colloidal mud to achieve high-flow continuous injection, low labor intensity, low downhole transportation, and can control a large fire area of ​​10-20m at the same time, and will not cause a lot of leakage, especially for large-area fire. The fire in the district is even more advantageous.

In practice, it is also found that when the colloidal mud covers the fire source from top to bottom, the gelation speed is increased and the permeability is deteriorated in the high temperature zone, and a colloid layer is formed on the top of the fire source, which affects the fire in the lower part of the colloid layer. To this end, they determine the gelation time of the colloidal mud according to the judgment of the position of the fire source point to control the gelation time. The control of the pre- and post-gelation time of the fire source point is a technological innovation for the successful fire extinguishing of the 305 stop-line line in a short time. Once there is a sign of a fire in the wind, such as the presence of CO or kerosene, analyze and explore the location of the high temperature immediately, and do not be blinded by illusions. This time, through careful analysis, it is more accurate to judge the high temperature point and lay a solid foundation for rapid governance. According to the actual geological conditions of the stop line, spontaneous combustion often occurs at the two ends of the stop line and the top of the coal seam. Therefore, drilling and grouting is an important method for stopping the fire.

Application of 7 fly ash in spontaneous combustion of coal seam in Xinglongzhuang Coal Mine

Zhangzhou Mining (Group) Co., Ltd. Xinglongzhuang Coal Mine developed fly ash into the material for underground fire prevention and grouting, turning waste into treasure, reducing environmental pollution and discharge costs, reducing the cost of fireproof grouting, economic benefits and Social benefits are significant. The coal seam of Xinglongzhuang Mine belongs to the coal seam which is easy to spontaneously ignite. The injection of yellow mud slurry is one of the main fire prevention measures for many years since the construction of the mine. There are two yellow mud grouting stations in the east and west wind shafts, with an average annual consumption of more than 20,000 m3 of loess. Fly ash is boiler ash collected by electric power boiler boiler dust collector. The annual coal discharge of the coal slime thermal power plant is about 90,000 tons. It has been transported to the subsidence area for backfilling. It not only consumes a lot of transportation costs, but also needs to pay a large amount of emission fees. After analysis, it is believed that fly ash can replace loess as a fire-fighting grouting material, and it has already been verified by the application of coal mines such as Nanxun and Baodian, and it has been developed into a fire-resistant material with mature technology and feasible scheme.

Because fly ash is a relatively small bulk material, in order to meet the requirements of fire prevention and transportation, it is necessary to prepare a slurry mixture with a solid-liquid ratio of about 1:2, so a stirring mechanism slurry is adopted. The process flow is: fly ash → fly ash silo → quantitative feeder → FU powder conveyor → humidification mixer → mixing tank spray → slurry pool → grouting vertical hole → underground. A Φ400mm×400mm electric feeder with a feeding capacity of 30t/h was installed in the dry ash outlet of the 5m plane under the fly ash silo, and the dry ash was fed into the FU270 chain conveyor. After the dry ash is transported to the pulping station outside the warehouse through the FU chain machine, the water is humidified by the mixer and enters the slurry tank. After being stirred by the mobile mixer, it reaches the vertical hole and is transported to the underground. The dewatering property of fly ash is good and easy to accumulate, which overcomes the disadvantages of yellow mud slurry flowing easily. After the fly ash slurry enters the loose body, it will dehydrate and accumulate quickly, which plays a good role in plugging and sealing. The fireproof effect is better than yellow mud slurry. . This achievement will save at least 600,000 yuan for loess material and about 200,000 yuan for fly ash. The use of fly ash not only reduces environmental pollution, but also reduces the loss of loess, which is conducive to the protection of cultivated land resources.

8Utilizing fly ash colloid instead of loess as fire protection material

Yanzhou Mining (Group) Co., Ltd. Dongtan Coal Mine uses the power plant fly ash to replace yellow mud as the fire-fighting raw material, and injects the coal ash colloid into all possible locations where the fire is possible, so that the fly ash colloid is fully exposed to the coal particles to prevent it from happening. The oxidation reaction produces a natural fire hazard in the coal seam and makes full use of industrial waste. The fly ash grouting system includes two parts: a ground grouting station and a downhole grouting piping system. Ground grouting stations include dosing pumps, fly ash storage tanks, ash gutters, mixing tanks, grouting vertical holes and other equipment. The downhole grouting pipeline system refers to the grouting pipeline from the grouting vertical hole to the various locations of the mine. Compared with the yellow mud system, its structure is simpler. The fly ash of Dongtan Mine Power Plant is directly sent to the fly ash storage tank through the quantitative pump. When grouting, open the valve at the bottom of the storage tank, use the electric lock to quantitatively discharge the fly ash, and at the same time open the water gun pump, and introduce the fly ash into the mixing tank through the guiding ash, the fly ash: water = 1:1, Then use a mixer to stir evenly, and then inject the slurry into the desired slurry through the grouting vertical hole and downhole piping system.

The advantages of the fly ash grouting system are as follows: thickener can be added to the pulping station of the ground pulping station to increase the density of the fly ash; according to the actual situation on the site, the mud pump or the grouting machine is used to grout the pipe A thickener is added to the road to control the gelation time according to the change of the thickening dose. The Dongtan Mine can harvest 3 working faces per year, and it needs to grout 5 to 6 stop lines. Since the prevention was in place in time, there has not been a spontaneous coal seam fire accident since 2000. Immediately after the coal mining face is closed, the fly ash thickened colloid is injected into the stop line to ensure that the natural fire hazard of the coal seam is eliminated at the beginning of the closure. At the same time, when the working face is recovered, the grouting holes shall be constructed for the stop mining line of the adjacent goaf, and the fly ash colloid shall be injected into the adjacent goaf through the grouting hole to prevent the stop of the adjacent goaf. The line is naturally ignited. After adopting the fly ash grouting system, the cost of processing industrial waste products by the power plant is reduced, and the annual raw material cost, labor cost, fire-fighting material cost and equipment cost are 1.9 million yuan.

9 fly ash colloid integrated fire prevention system

Since the launch of the Baodian Coal Mine of Zhangzhou Mining (Group) Co., Ltd., many serious spontaneous combustion fires have occurred, posing a great threat to safety production. Especially with the increasing depth of mining, the number of spontaneous combustion has increased year by year. In order to effectively prevent and quickly control and extinguish fires in an emergency, they developed a fly ash colloid integrated fire prevention system to achieve fly ash instead of loess for grouting and fire prevention. The mine 5307 integrated mechanized top coal mining face is the fourth section of the Wu mining area, and the lower three sections have been taken. The side of the working face is along the empty space, the track along the trough is the empty roadway, the eleven chambers are exposed along the air side, the new squatting room is 3, the rail is uphill and the three rails are uphill. Cut the end of the eye to focus on fire prevention, the treatment area is large, and the injection of fly ash composite colloid is selected here.

The water-cement ratio of the fly ash composite colloid is 1:1, the filling volume is 500m3, and the filling time is 10h. 1307 Xishun trough is a transport lane, and there is a 32m isolation coal pillar in the goaf of a mining area; Dongshun trough is a track lane. The cut-eye is arranged in the lower part of the center of the 1303 section, and the stop-and-go line is in the lower part of the 1308 section. The cut-eye will directly expose the 1303 Yunshun-linking lane during the tunneling process, which will cause a large amount of air leakage to the goaf, and the coal seam will spontaneously ignite. Possibly, therefore, it is decided to fill the fly ash solidified material at this place for sealing. The water-cement ratio is 1:1, the pulping effect is good, the glue forming quality is high, the total filling volume is 240m3, and the filling time is 5h. They realized the following: The fly ash colloid integrated fire prevention system can prepare various concentrations of slurry to adapt to different conditions of grouting; adding a suspending agent to the high concentration slurry can be smoothly transported to the pulping site through the colloidal integrated fire prevention system. It does not block the pipeline; it can realize a variety of new fire-extinguishing materials such as thick flow injecting thickened colloid, gel, composite colloid and solidified filling material by changing the admixture. The perfect automatic control system can ensure multi-function grouting. The stable operation of the glue-inhibiting fire-extinguishing system improves the operability of the system; the fly ash discharged from the thermal power plant is 100m3/d, which can fully meet the needs of underground grouting.

10 colloid and mud combined with good fire prevention effect

Zhangzhou Mining (Group) Co., Ltd. Baodian Coal Mine combined organic rubber fire extinguishing technology with yellow mud slurry fire extinguishing, successfully managed the spontaneous combustion of 1301 working face, 1304 working face and 1310 comprehensive mechanized top coal mining face. Good results. The gel is based on sodium metasilicate (water glass), sodium bicarbonate is used as a coagulant, and evenly mixed with water. The gel injection process uses two water tanks to mix the water glass with the accelerator, and then injects it into the borehole through the TBW-50/15 mud pump. It can only be injected 2 to 3 m3 per hour, which is only suitable for the local part. The roof of the roadway and the airspace are blocked. In order to implement effective fire prevention and control for large-scale goafs, they carried out research on this topic. First, the water glass is mixed into the yellow mud slurry at the ground grouting station, and is transported to the place where the grouting needs to be grouted by the grouting system; after the mud reaches the construction site, the operator starts to start the colloidal injection pump and adds it to the bin. The coagulant; the coagulant and the mud mixed from the screw pump can be directly transported to the goaf through the grouting pipe before being glued, or can be injected into the borehole through the high pressure hose on the diverter. The solidification time of the colloidal slurry can be controlled by controlling the rate of addition of the coagulant depending on the length of the mixed liquid transport distance or the required solidification time. Generally, it is glued in 2~3min, and water glass is added in proportion of 3%. If the pulping speed is 50m3/h, the accelerator addition speed is controlled at 1700kg/h.

The application practice shows that the efficiency is 15 to 20 times higher than that of the injection gel by the injection of 50m3 per hour. The colloidal mud can accumulate continuously, fill the entire space, and solidify in a short time, which can effectively block the leakage and control the roof fire; The colloidal mud absorbs a large amount of heat during solidification, which can rapidly cool the surrounding environment; it greatly reduces the phenomenon of slurry leakage when the original yellow mud is injected, and reduces waste and environmental pollution. After the mine applied the gel-injected mud to the working face, the stop line and the roadway along the empty road, there was no spontaneous combustion in the advanced treatment area.

Application of 11 polymer coagulant in coal mine fire prevention

Zhangzhou Mining (Group) Company Dongtan Coal Mine used MCA polymer + water glass gel in the fire in the coal mine. Through the ground proportioning test and underground field test, the best ratio was found, and the glue injection process was explored and improved. It has achieved good application results and has broad application prospects. The gel fire prevention technology is to add MCA polymer and water glass to water in a certain proportion to thicken the water, and pump the two liquids into the mixer after injection into the loose coal body, and the two liquids flow. Side glued. Under the action of the pump pressure, the mixed liquid is injected into the tiny pores of the coal body crack, so that the oxygen cannot penetrate into the coal body. During this process, the mixture continuously absorbs heat to lower the temperature of the coal. Under the dual action of cooling and isolation, the self-oxidation and heat release performance of the coal body is reduced, and the self-ignitability is lowered, which effectively suppresses the spontaneous combustion of the coal body. The hidden danger points of the spontaneous combustion of the coal seam are usually in the high-rising area of ​​the roadway, the roof rebuilding section, the adjacent or upper layer working face, and the cutting line and the stop line, etc., and the ratio of the gel forming time is relatively short. According to the experimental results, there are 3 groups that can meet the requirements of underground fire-fighting and injection-injection. The initial setting time is 30-70s, and the final setting time is about 2min. According to the water ratio, the two solutions are prepared in the downhole and the water glass is prepared on the ground, and the MCA solution is prepared in the downhole. The test shows that with the increase of the amount of MCA polymer coagulant and water glass, the gelation time is gradually shortened; the effect of MCA polymer coagulant on the gelation time is larger than that of water glass, and the larger the dosage, the shorter the time; When the MCA polymer coagulant is 3%, the gelation time is shortened correspondingly with the increase of the amount of water glass, but the shortening rate is not fast; when the MCA polymer coagulant is 4%, with the amount of water glass The increase of the gelation time is faster; when the final setting time exceeds 150s, it can be used to inject a large amount into the goaf, so that the colloid has time to flow and penetrate deep into the goaf; when the final setting time is less than At 150s, it is mainly used for the injection of the roof of the roadway to achieve the purpose of rapid gel filling and plugging. When the final setting time is less than 60s, it is mainly used for short-distance conveying and rapid filling and plugging.

Application of 12 fly ash thickener in mine fire prevention

Yanzhou Mining (Group) Co., Ltd. Jining No. 2 Coal Mine cooperated with Xuzhou Yichuang Chemical Co., Ltd. to develop a relatively mature self-ignition and fire prevention technology based on PCAS viscous agent injection coal slurry, and was awarded the 2004 coal industry. Ten major scientific and technological achievements." Although most of the undisturbed fly ash can be slurried after adding water, the cohesive cohesive force is weak, the adhesion to the floating coal and the wrapping power are poor, the airtightness is insufficient, the water retaining ability is poor, and the thixotropy is also poor. Therefore, it is easy to block the pipe when transporting the pipeline, it is difficult to transport long distances, and the required water-cement ratio is also large. After entering the underground goaf, the same beach is scattered with sand, and a large amount of fine ash flows along with the water. PCAS viscous agent is to study the difference between yellow mud and fly ash. According to the requirements of “flame retardant design”, the surface condition of the aqueous solution is changed at the moment of mixing of fly ash + PCAS + water, which greatly reduces the surface of water. At the same time, the PCAS thickener also increases the viscosity of the "medium" environment in which the fly ash is located, and uses a large number of hydration membranes to tie up 70% to 80% of the fine particles (less than 80 mm of particles) in the fly ash. In the network structure formed by the hydration film.

This multi-layer network structure can be formed in a short time after adding water and stirring. This new structure fly mortar has the same function as yellow mud slurry, even larger than the yellow mud slurry in water content, water retention time and adhesion, achieving and achieving the flame retardant (oxygen barrier, cooling) and fire extinguishing of yellow mud slurry. Features. The addition of a PCAS viscous pulverized coal slurry contributes to the main function of flame retardant and fire extinguishing, in that it significantly increases the wetting force of water for materials that are not easily wetted. When a pulverized coal slurry containing a PCAS viscous agent is sprayed onto the surface of the combustion product, water adheres to the combustion surface and diffuses on the surface of the combustion material to cool the combustion surface, preventing pyrolysis of the combustion product, thereby causing flame Combustion and surface burning are extinguished. Wetting water can also quickly penetrate into the interior of the combustion to stop the burning of deep burning and extinguish the smoldering fire. The application practice of Jining No. 2 Coal Mine for more than four years proves that the coal ash slurry grouting fire prevention technology with PCAS fly ash viscous agent as the carrier has low cost, remarkable effect, turning waste into treasure, and can prevent and control well. The spontaneous combustion of coal mines has a great value for promotion and application.

references

1. Tang Yaoyong, Kong Lingchang, Dong Xiaodong, Application of Integrated Fire Prevention Technology in CO Overrun Area of ​​Closed Goaf, Coal Mine Modernization, 2008(1)

2. Xie Huadong, Meng Jingzhan, MCA polymer accelerator used in coal mine gel fire prevention technology, Shandong Coal Science and Technology, 2006 (5)

3. Jiang Xiyin, Ren Chunmin, application of fly ash thickener in mine fire prevention, coal mine modernization, 2006 (S1)

4. Li Wei, Ruan Guoqiang, Li Feng, Research and Application of Fly Ash Colloid Integrated Fire Prevention System, Shandong Coal Science and Technology, 2004(6)

5. Xie Huadong, Wang Xuyou, the application of fly ash instead of loess for mine fire prevention materials, coal mine modernization, 2004 (3)

6. Wen Hu, Qiu Chunliang, Chen Anming, Zhang Xinhai, self-ignition colloid fire prevention technology for coal seams in fully mechanized caving face, coal mining, 2004(2)

7. Meng Xiangjun, Chen Longgao, Chen Jianfeng, Yu Xiaobo, Application of fly ash in preventing spontaneous combustion of coal seams, Shandong Coal Science and Technology, 2004(2)

8. Wang Xuyou, Zhao Dianchen, Song Xianming, Meng Jizhan, application of sodium metaaluminate in coal mine gel fire prevention technology, coal mine modernization, 2003 (4)

9. Tiger, Xu Wonderful, Wang Chunyue, Zhang Xinhai, Application of Thickened Colloid Fire Prevention Technology in Dongtan Coal Mine, Coal Science and Technology, 2003(1)

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