Potassium dihydrogen phosphate is widely used in industrial and agri- culture. The solvent extraction method for producing KH2PO4 from the more cheap extraction phosphoric acid and potassium chloride has gained growing attention recently. To evaluation influence SO42– on the crystallization KH2PO4 it is nessesary comprehensive knowledge of the phase equilibria in the system K+// H2PO42–, SO42– – H2O. The ternary system KH2PO4 – K2SO4– H2O was determined at 25 °C by the improved isothermal method of section.
