WO2015007103A1 - Method for preparing retardant slurry containing coal ash for controlling fire disaster in coal field - Google Patents

Abstract

A method for preparing a retardant slurry containing coal ash for controlling the fire disaster in a coal field comprises the steps of adding coal ash, aluminium phosphate, magnesium chloride, sodium carboxymethylcellulose, sodium silicate and sodium bentonite material in water to prepare a coal ash thickening slurry having high retardation and high-temperature resistance. The prepared thickening slurry is conveyed to burning coal seams or coal fractures through a grouting pipeline by a high-pressure screw pump. After a period of time, the retardant slurry can be thickened and solidified into a soft solid form. The retardant slurry can resist a high temperature of above 1000°C, form a hard block structure after water evaporates, and hermetically cover the coal body and block the fractures. The retardant slurry containing coal ash is low in costs, safe and environmentally friendly, and has significant control effects on the fire disaster caused by spontaneous combustion of coal in the coal field, and a good application prospect.

Description

 Method for preparing fly ash resistant slurry for treating coal field fire

Technical field

 The invention relates to a coal field fire treatment method, in particular to a preparation method of a fly ash resistant slurry for treating a coal field spontaneous combustion fire.

Background technique

Coal is China's main energy source, accounting for about 70% of primary energy production and consumption structure. From the perspective of spatial layout, China's coal resources are mainly distributed in the northwest and north China. Among them, Xinjiang, Inner Mongolia, Shanxi, Shaanxi, Ningxia, Gansu and other six provinces and regions have about 80% of the country's proven coal reserves, which is related to China's energy. Strategic energy base for safety and economic development. With the further westward shift of China's coal industry layout, the strategic position of the above-mentioned regions has become increasingly prominent. However, due to the long-term drought and low rainfall in these areas, the coal seams are thick and shallow, and the indiscriminate mining of small coal mines leads to frequent fires in the coal fields and fire areas, including Xinjiang, Inner Mongolia and Ningxia. Xinjiang has a total of 44 coal fire, fire area of 9.92 million m ^2, in coal-fired loss amounted to 5.52 million t, the threat of the fire district reserves 47.7 billion t, annual emissions of greenhouse gases C0 ₂ reached 12.38 million Wuda, Zhuozishan There are also 19.03 million m ² coalfield fire zones in several coal fields such as Erdos, Zhungeer and Gulaben. The total area of the Wuda coalfield fire zone in 2009 was 4,754,000 m ² , an increase of 40 from 2004. %. Ningxia's existing coalfield fire zone is 394.56 million m ² , and the amount of coal directly burned and lost is nearly 1 million tons per year. The coal reserves under the fire zone are 7872.58 million tons. Coal-fired fires not only directly burn non-renewable coal resources, but also indirectly cause dozens of times of stagnant resources to be exploited, and directly threaten the safe production of coal mines. They also cause soil desertification, vegetation death, ground collapse, steam, blue smoke, and heat waves. Surface germination, crystal sulphur, coal tar, high temperature crater, a large number of toxic and harmful gases such as C0, C0 ₂ and S0 ₂ are discharged into the air, seriously jeopardizing the local ecological environment and groundwater resources, local areas have affected the survival of residents. The problem of coal fire has become a major problem that jeopardizes China's energy strategy security and ecological harmonious development, and has attracted the attention of scholars from many countries around the world.

At present, the domestic coal area fire area treatment methods are mainly stripping method, water injection and grouting method. However, the peeling method is less safe and has a large amount of work. Due to the formation of a large number of suspended and collapsed areas in the fire zone, the bulldozers and excavators used in the stripping construction are likely to be trapped in the voids, causing casualties and major economic losses. In addition, if the underground coal fire situation is judged It will cause oxygen supply after stripping, which will cause the coal fire to spread rapidly and lead to the expansion of the fire area, increasing the danger and difficulty of fire extinguishing. The method directly peels off the buried coal fire, and has large engineering cost and high cost, and is difficult to implement; when the fire zone is used for blasting, the blasting temperature is generally not higher than 40-60 ° C, but the blasting hole in the fire zone is Frequently encountered high temperatures of 100 ° C or even hundreds of degrees, so that the fire area can not be blasted smoothly. Water injection grouting combined with loess cover is the most important means of controlling coal fire. Since water and soil are easy to obtain and low in cost, water injection grouting is the most economical fire extinguishing method; but the water slurry will flow along the coal rock crack or the old kiln passage to the lower part, not to the fire. Uniform and effective coverage of the area requires a large number of drilling holes and construction of many fish scale pits for a large number of long-term water injections, in order to achieve a gradual cooling of the coal body; due to the small flow path of the water slurry, according to statistics, more than 80% of the water does not absorb heat and cool down. In the process of water injection and grouting, when the water is collected at the high temperature fire source, it will easily lead to water gas explosion, causing casualties; meanwhile, when there is coal mine production in the lower part of the coal fire, grouting is also prone to slurry collapse. , threatening the safe production of underground coal mines. Therefore, the traditional method of water injection grouting can not fully meet the needs of coal fire treatment.

Summary of the invention

 Technical Problem: The object of the present invention is to provide a method for preparing a fly ash-containing resisting slurry for treating coal field fires with simple method, good resistance, high temperature resistance, high dehydration, and low cost in view of the problems in the prior art. method.

 Technical Solution: The method for preparing a fly ash resistant slurry for treating a coal field fire of the present invention comprises using fly ash, aluminum phosphate, magnesium chloride, sodium carboxymethyl cellulose, water glass, sodium bentonite and water, The 8% of the carboxylic acid is added in an amount of 25% to 30% of the aluminum ash, 2% to 4% of the aluminum phosphate, 2% to 5% of the magnesium chloride, and the 8% to 1.5% of the carboxylic acid. Methyl cellulose sodium, fully stirred to make a mixed solution A;

 b. Add 3%~5% water glass and 1%~2% sodium bentonite in water by mass percentage, and mix well to make mixed solution B;

 c Add solution B to solution A, solution B and solution A are mixed at a mass ratio of 1: 2, and mix well during the addition.

 Advantageous Effects: The method for preparing a fly ash resistant slurry for treating a coal field fire is prepared by adding fly ash, aluminum phosphate, magnesium chloride, sodium carboxymethyl cellulose, water glass, sodium bentonite and the like to water. The mixture is thoroughly stirred and mixed to prepare a thickened slurry of fly ash having high resistance and high temperature resistance. The prepared thickened slurry is transferred to the burning coal seam or coal seam by a high pressure screw pump through a grouting line. The material has strong heat absorption and cooling ability, and is resistant to high temperatures above iooo °c, so it can effectively extinguish and reduce the temperature of the burning fire area of the coal field; and has good resistance and can effectively inertize the surface active structure of the coal. Compared with the prior art, the resistance of the resistive material is improved by 3 to 5 times; at the same time, when the fly ash-containing resisting slurry covers the coal seam or accumulates in the coal body crack for a period of time, it becomes thickened soft. The solid can tightly cover the coal body and block the coal body cracks, and isolate the coal and oxygen, which can effectively prevent oxygen supply in the fire area. The resistive slurry of the invention has low cost, safety and environmental protection, and has obvious effect in controlling coal field fire, and has good application prospect.

detailed description

 The preparation method of the fly ash-resistant slurry for treating coal field fires adopts fly ash, aluminum phosphate, magnesium chloride, sodium carboxymethyl cellulose, water glass, sodium bentonite and water materials, and the preparation process thereof is as follows :

8%~1。 8%~1。 8%~1 8%~1%%%%%%%% 5% sodium carboxymethylcellulose, fully stirred Mixing solution A;

 b. Add water 3%~5% water glass and 1%~2% sodium bentonite in water, stir well to form mixed solution B;

 c Add solution B to solution A. Solution B and solution A are mixed at a mass ratio of 1:2. Stir well and mix well during the addition. A resist slurry containing fly ash is formed in about 5 minutes.

 If the speed of thickening is required to be faster, the mass ratio of the two materials of the B solution is taken as a larger value; if the thickening speed is required to be slower, the mass ratio of the two materials of the B solution is taken to a smaller value.

 Example 1 First, add 250 kg of fly ash, 20 kg of aluminum phosphate, 20 kg of magnesium chloride and 8 kg of sodium carboxymethylcellulose in 1000 kg of water, stir well and mix well to prepare a mixed solution with a concentration of 23%; secondly, at 500 kg Adding 15kg of water glass and 5kg of sodium bentonite to the water, mixing well to prepare a mixed solution with a concentration of 3.8%; mixing the two solutions, stirring well, about 5 minutes, forming a new type of resistance containing fly ash Slurry.

 8%的混合溶液; Secondly, first, in a 1000 kg of water, 300 kg of fly ash, 40 kg of aluminum phosphate, 50 kg of magnesium chloride, and 15 kg of sodium carboxymethyl cellulose, and stirred well, to prepare a mixed solution having a concentration of 28.8%; Adding 25kg of water glass and 10kg of sodium bentonite to 500kg of water, mixing well to prepare a mixed solution with a concentration of 6.5%; mixing the two solutions, stirring well, about 5 minutes, forming a fly ash-containing mixture A new type of resistive slurry.

 The second embodiment, a mixture of 270 kg of fly ash, 30 kg of aluminum phosphate, 30 kg of aluminum phosphate, 30 kg of magnesium chloride, and 10 kg of sodium carboxymethyl cellulose, and stirred well, to prepare a mixed solution having a concentration of 25.4%; Adding 20 kg of water glass and 10 kg of sodium bentonite to 500 kg of water, and mixing well to prepare a mixed solution having a concentration of 5.7%; mixing the two solutions, and uniformly stirring them for about 5 minutes to form a fly ash-containing mixture. A new type of resistive slurry.

 The above-mentioned prepared fly ash-containing resisting slurry is respectively transported to the burning coal pile through a screw pump and a pipeline, and the temperature of the coal pile is up to 500 ° C or more, and the resisting slurry is quickly uniformly covered on the coal pile. The coal pile fire was quickly extinguished, the temperature of the coal pile was rapidly reduced, and the temperature of the coal pile was reduced to normal temperature in a short time. For spontaneous combustion of high temperature coal, the effect of extinguishing fire is significant.

Claims

Claim

A method for preparing a fly ash resistant slurry for treating a coal field fire, characterized by: using fly ash, aluminum phosphate, magnesium chloride, sodium carboxymethyl cellulose, water glass, sodium bentonite and water The material, the preparation method comprises the following steps:

 a 8% by weight of carboxymethyl cellulose, 2% ~ 4% of aluminum phosphate, 2% ~ 5% of magnesium chloride, 0. 8% ~ 1.5% of carboxymethyl cellulose Sodium, fully stirred to make a mixed solution A;

 b. Add 3%~5% water glass and 1%~2% sodium bentonite in water by mass percentage, and mix well to make mixed solution B;

 c Add solution B to solution A. Solution B and solution A are mixed at a mass ratio of 1: 2, and thoroughly mixed and mixed during the addition.