METHOD OF PREPARING SODIUM SULFIDE Russian patent published in 1999 - IPC

FIELD: chemical industry, more particularly creation of new and reconstruction of existing sodium sulfide production processes. SUBSTANCE: method comprises reductive roasting of barium sulfate, crushing the resulting barium sulfide melt, leaching it and converting barium sulfide into sodium sulfide by reaction with sodium sulfate filtering suspension to give sodium sulfide solution and barium sulfate precipitate recycled to reductive roasting stage. In this case, conversion process is carried out by introducing solid waste products, solutions and sodium sulfate sewage into solution or pulp from barium sulfide melt crushing and leaching stage at initial barium sulfide concentration of 18-30 wt % and amount of sodium sulfate of 100-110% of stoichiometric amount. Water- insoluble admixtures present in barium sulfide melt are withdrawn from process either continuously or as they accumulate by clearing barium sulfide pulp prior to conversion of barium sulfide into sodium sulfide. Reductive roasting of barium sulfate is carried out by using solid waste products of carbonaceous materials, e.g. oil coke fines, metallurgical coke siftings or the like as reducing agents. Sodium sulfide solution is boiled down in single stage in vacuum evaporation device to concentration of 63-65 wt %, whereupon aqueous melt is granulated or poured into drums where is becomes solidified. EFFECT: high intensity of processes of conversion and filtration of suspensions and top guality of the final product. 4 cl