Meikuang Anquan (Jun 2024)
Research on preparation and performance of a new type of inorganic paste fire preventing and extinguishing filling material in Shendong Mining Area
Abstract
In order to solve the problem of many coal remains, easy to spontaneous combustion and difficult to be sealed in the goaf near the two ends of roadway of the working face in Shendong Mining Area, this paper proposes a new type of inorganic paste fire preventing and extinguishing filling material, which can efficiently and quickly fill the upper and lower corners of the working face. Fly ash, slag and P·O·42.5 silicate cement, which are easily accessible in the vicinity of Shendong Mining Area, are used as the main raw materials of the paste, and the physical properties and chemical compositions of the materials are investigated through indoor tests, and the optimal ratio of the paste and the amount of additives are determined through the paste liquidity test, the paste solidification test, the paste expansion test and the paste filling strength test. The test results show that: the slag base paste has good self-expansion, the self-expansion rate can reach 5.6% in 7 days, and the initial setting time is short, which can meet the strength requirements of the project. The best proportioning scheme of the paste fireproofing material is cement : fly ash : slag = 1 : 4 : 20, and the mass fraction is 78%, and the addition amount of J85 accelerator is 6%. The engineering application shows that, after using the preferred paste filling material for corner filling and sealing, the air leakage in the mining airspace is reduced to 30% of that before filling, the CO volume fraction is reduced from 120×10−6 to 46.5×10−6, the O2 volume fraction is reduced to less than 10% at a point of about 80 m in depth of the strike length of the mining area, and the strike length of the dispersion zone + oxidation zone in the goaf is shortened from 160 m before filling to 80 m.
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