Desulphurisation of coal - by treating with aq. soln. of alkali or alkaline earth metal sulphite or bi:sulphite

摘要

Desulphurisation of particulate coal is effected by contacting with an aq. soln. contg. one or more alkaline(ne earth) metal sulphites and-or bisulphites. The treatment is capable of removing elemental and pyritic S and some organic S without causing oxidn. of the coal or reducing its heating value. The treatmetn temp. is pref. 100-500 degrees C esp. 200-500 degrees C or 175-350 degrees C when alkali metal (bi)sulphites are used. The contact time is pref. 0.5-5 (esp. 0.5-4) hr. The pressure is pref. 25-500 psig. The soln. pref. has a cocn. of 0.1-20 (esp. 2-10) wt. % and is used in an amt. sufficient to give a mixt. contg. 5-70 (esp. 10-40) wt.% coal. The prefd. active agents are K2SO3 and Na2SO3.