METHOD FOR PRODUCING POTASSIUM SULFATE Russian patent published in 1997 - IPC

FIELD: production of fertilizers, production of high-efficiency chlorine-free potash fertilizer - potassium sulfate. SUBSTANCE: potassium sulfate is produced by conversion of sodium sulfate or mirabilite mineral with potassium chloride in aqueous medium to form at first process step, glaserite and glaserite liquor. To be able to use as starting materials sodium sulfate or mirabilite contaminated with impurities first conversion step is carried out to produce glaserite liquor at potassium-to-sulfate ion ratio equal to 0.7-1.0 equivalent percent in liquor. The latter is thickened by evaporation to isolate salt slurry which is subsequently used to treat saturated sodium sulfate solution produced from off-grade sodium sulfate. In this manner, insoluble impurities are removed from sodium sulfate. EFFECT: higher efficiency. 2 cl, 1 dwg, 2 tbl