SU867323A3 - Agent for preventing coal self-ignition - Google Patents

Abstract

1392984 Dust-laying compositions CHEMISCHE FABRIK KALK GmbH 19 April 1972 [14 June 1971] 18138/72 Heading C4X [Also in Division E1] A method of suppressing spontaneous ignition of coal in an unventilated underground gallery comprises applying to the coal surface a powder comprising CaCl 2 and/or MgCl 2 and containing a non-ionogenic wetting agent, the gallery thereafter being left unventilated. The wetting agent may be a dialkylphenylpolyglycol ether, alone or with one or more other alkyl, aryl or alkaryl polyglycol ethers, and may constitute 0À5-5% by wt. of the powder. An inert substance, e.g. stone powder, dried clay, calcium sulphate or carbonate, boiler ash, industrial dust or a mixture thereof, preferably of grain size less than 0À2 mm., may be included in an amount 0À1-5 p.b.w. per 1 p.b.w. hygroscopic salt; NaCl is particularly preferred. Preferably over 80% by wt. of the CaCl 2 and/or MgCl 2 is of grain size less than 1 mm., and over 60% of less than 0À3 mm. The powder is applied to the coal surface by a compressed air stream.

Description

(54) MEANS FOR PREVENTION OF SELF-IGNITION The invention relates to the mining industry and can be used to prevent self-ignition of coal. The use of powdered calcium chloride to prevent coal from spontaneous combustion is known, as well as the use of fatty alkylphenols for this purpose. The disadvantage of using these substances separately is the low efficiency of prevention of coal spontaneous combustion. It is also known an agent for preventing coal from spontaneous combustion, which contains a hygroscopic salt and a wetting agent 2. A disadvantage of using a known substance is the high cost of use and a relatively small antipyrogenic ability when used in mining and mined-out spaces. The purpose of the invention is to prevent coal from spontaneous combustion and its clusters in the goaf. The goal is achieved by using chloride powder as a hygroscopic salt. calcium or magnesium, and as COAL of the wetting substance is dialkylphenyl polyglycol ether with 5-20 glycol residues in the glycol group and C-Cd alkyl in the following ratio of components, weight. h: Powder of salt. 95.0-99.5 Wetting agent 0.5-5.0 Moreover, the agent additionally contains calcium sulfate as an inert diluent in an amount of 0.1-5 parts by weight. on 1 weight. hygroscopic salt. The agent for preventing spontaneous combustion of coal contains finely dispersed calcium chloride or magnesium chloride. The grain sizes of the fine substance are established depending on the nature of its use, the upper limit of the grain size is determined by the possibility of its pneumatic injection into the formation with the help of compressed air, as well as the possibility of mining on the surface. This can be achieved if the grain size of the salt powder is greater than 80% by weight is less than 1 mm and more than 60% by weight is less than 0.3 mm. Such a fine powder of calcium chloride or magnesium becomes more effective when a wetting agent is added to it, for example, non-ionic wetting agents. However, it is very important that the salt solution formed directly (after pressing the salt particles onto the treated surface of the coal, completely cover the surface of the coal and, above all, filled all the pores and cracks of the corner, preventing the access of oxygen to air.

For this purpose, non-ionic wetting agents are used, which so reduce the surface tension of the resulting hygroscopic salt solution in relation to the coal that the solution can quickly penetrate into the smallest capillaries. Such a wetting agent is dialkylphenyl polyglycol ether with residues of glycol 5-50 in the glycol ether group and alkyl groups with 1-9 carbon atoms. This wetting agent is added to the hygroscopic salt powder in amounts of 0.5-5% by weight with respect to the finished mixture.

The wetting agent is mixed with a powder of salts.

It is possible to use said wetting agent with other wetting agents that do not form ions, for example, with alkyl-aryl- or alkylarylglycol ethers. Such mixtures should contain, on one weight part, of dialkyl polyglycol ether, 0.4-1.0, the maximum weight parts of the other non-forming ions of the wetting substances.

The agent for preventing the spontaneous combustion of coal also contains, in addition to fine hygroscopic salts and wetting agents, and crushed inert dry materials, the particle size of which is less than 0.2 mm. Such inert diluents are ground inert dry materials: stone dust, dry clay, natural or synthetic calcium sulphate or calcium carbonate, boiler ash, factory dust with a minor amount of silicic acid or a mixture of such inert materials. An inert diluent is added in an amount of 0.1-5 parts by weight. on 1 weight. hygroscopic salt.

To prepare an agent to prevent spontaneous combustion, coal takes an equal amount of weight parts of calcium chloride powder with 85% by weight of CaCr, calcium sulfate to i.pOiUKa, and the mixture is intensively mixed and 3% by weight of a wetting solution is added with stirring substance, which consists on 2/3 of its weight from dimethylphenyl polyglycol ether with twelve glycol residues and on / 3 from polyglycol ether. nine glycol residues.

Under the action of moisture absorbed by the hygroscopic salt from the mine atmosphere, a protective layer is formed on the surface of the coal treated with this agent, protecting the coal from oxidation.

The effectiveness of the proposed agent was tested in mine conditions, namely, the surface of the pillar was treated with coal to prevent spontaneous combustion of the coal for several years, during which time the carbon monoxide content was sampled in the outflow. 5 The carbon monoxide content in the ventilation flow did not exceed 26 million shares. For comparison, a plot was allotted in the mine, where the surface of the coal massif was not treated with the tool, and where a smoldering fire occurred during the testing period.

The test results are shown in the table.

Thus, the tool serves as an effective measure to prevent coal from spontaneous combustion.

from 26. 05.64 a smoldering fire arose as a result of spontaneous combustion

Claims (2)

Invention Formula 1, Means for preventing coal from spontaneous combustion, containing a hygroscopic salt and a wetting agent, characterized in that, in order to prevent coal and its accumulations in the exhausted space to ignite, calcium or magnesium powder is used as a hygroscopic salt, and as a wetting agent - dialkylphenylpolyglycol ether with 5-20 glycol residues in the glycol group and alkyl in the following ratio of components, parts by weight: Salt powder95.0-99.5 Wetting agent 0.5-5.0 2. The agent according to claim 1, characterized in that it additionally contains calcium sulphate as an inert diluent in an amount of 0.1-5 parts by weight. on 1 weight. hygroscopic salt. Sources of information taken into account in the examination 1.Hrisonfova A.I. and others. Coal storage technology and measures 0 to reduce fuel losses, M ,, Nedra, 1970, p. 155-165. 2.Maevska V.M. Flame retardants for the prevention and extinguishing of endogenous underground fires. Izvebti higher education institutions. Torny 5 Journal, 1961, No. 8, p. 122-125 (prototype).