POTASSIUM SULFATE PRODUCTION PROCESS Russian patent published in 2001 - IPC

FIELD: industrial inorganic synthesis. SUBSTANCE: invention relates to technology of production of potassium sulfate and potassium chloride in aqueous media. Method involves interaction of ammonium sulfate solution with suspension of potassium chloride followed by isolation of double potassium-ammonium sulfate salt and treatment thereof with aqueous potassium sulfate solution obtained in succeeding dissolving and crystallization stages, separation of potassium sulfate on filter and returning mother liquor into the potassium chloride suspension preparation stage. Potassium sulfate form filters is dissolved in heated return solution. The latter is clarified and cooled to isolate desired product into solid phase. The product is separated from solution and dried, whereas cold solution is partly subjected to treatment of double potassium-ammonium sulfate salt and to the rest of cold solution is added water until potassium sulfate from filters is completely dissolved. Return solution obtained is heated and used to dissolve potassium sulfate. According to invention, return solution is mainly heated to 95-105 c, clarified solution is cooled mainly in vacuum to 25-35 C, treatment of double potassium-ammonium sulfate salt is carried out with cooled potassium sulfate added in amount ensuring liquid-to-solids ratio in suspension 0.7 to 2.0, and whole amount of potassium sulfate from filters or a part thereof is dissolved. In the latter case remaining part of potassium sulfate is used as second final product. White crystalline product contains more than 52% K₂O and less than 0.1% chloride anion, insoluble impurities being completely absent. EFFECT: increased purity of product. 4 cl, 1 tbl