METHOD OF CONTINUOUSLY PRODUCING POTASSIUM SULFATE FROM SODIUM SULFATE Russian patent published in 1998 - IPC

FIELD: industrial inorganic syntheses. SUBSTANCE: sodium sulfate and potassium chloride are brought into interaction with mother liquor of potassium sulfate to form glaserite, which is then separated from mother liquor and, combined with potassium chloride and water, is converted into potassium sulfate and mother liquor of potassium sulfate, whereas glaserite is crystallized. Remaining mother liquor is evaporated to incite pure sodium chloride to crystallize, which is then separated. According to invention, in mother liquor of glaserite, K₂/SO₄ molar ratio is higher than 3:1, better higher than 4: 1, and not higher than 5:1; and Na₂/SO₄ molar ratio higher than 8:1 and not higher than 11:1. This mother liquor is evaporated at 75 to 115 C to remove 29 to 42% of water avoiding direct precipitation of sulfates, in particular, glaserite, and to produce KCl-containing suspension, which is further utilized to isolate glaserite. EFFECT: facilitated potassium sulfate production. 5 cl, 2 dwg