A method for preventing the spontaneous oxidation of low-quality coal.

摘要

Low rank coal is treated to reduce its tendency towards spontaneous combustion by (a) contacting particulate coal with an aq. oxidant soln. (I) which becomes homogeneously distributed over the surface of the particles, without adding more than ca. 10 wt.% water to the coal; (I) contains an oxidising agent containing combined oxygen; (b) drying the wetted coal by heating to 100-400 deg.F to reduce the moisture content to that desired for the prod.; and (c) cooling to less than 100 deg.F. (I) pref. contains oxidising agent in high concn., e.g. substantially satd. A relatively mild, water solbule, oxidising agent is used, e.g. a perchlorate, chlorate, peroxide, hypochlorite or nitrate, the cations being metal ions, hydrogen or ammonium e.g. magnesium perchlorate or ammonium nitrate. The solution may be sprayed onto the coal, e.g. at a drop point or on a belt. Moisture content of the coal is increased by not more than 2 wt.%. Step (b) takes place e.g. at 150-250 deg.F.