METHOD OF PREPARING POTASSIUM SULFATE AND COMPLEX FERTILIZER Russian patent published in 2000 - IPC

FIELD: chemical industry, more particularly technology of preparation of potassium sulfate, potassium chloride and ammonium sulfate in aqueous medium by processing excessive solutions into complex fertilizer. SUBSTANCE: method comprises preparing potassium sulfate and complex fertilizer, reacting solution of ammonium sulfate and suspension of potassium chloride, isolating potassium-ammonium sulfate double salt and treating it with solution of potassium chloride, isolating the resulting potassium sulfate from mother liquor, washing it and recycling the mother liquor to prepare suspension of potassium chloride, and solution resulting from isolation of double salt is heated, and ammonium phosphate is added thereto under vigorous stirring in amount which adjusts K₂O:P₂O₅ ratio of 1.0:(1.0-3.0) in solution, and finely dispersed potassium chloride is then added to solution in amount which maintains desired K₂O:P₂O₅ ratio in fertilizer, the resulting suspension is sprayed and dried. Finely dispersed potassium chloride includes cyclone dust of concentrating potassium mill. EFFECT: more efficient preparation method.