Magnesium hydrogen phosphate and potassium salts prodn. - for use in fertilisers by reaction of potassium magnesium phosphate with mineral acid

摘要

In the prodn. of water-soluble salts from potassium magnesium phosphate and mineral acids, (A) potassium magnesium phosphate and the stoichiometric amount of mineral acid required for the formation of magnesium hydrogen phosphate are stirred into recycled mother liquor which has been heated to 40-90 deg.C, to give a readily stirrable reaction mixt. (B) after completion of reaction at approximately the same temp. the magnesium hydrogen phosphate is sepd. from the soln., (C) after slight evaporation and cooling the crystallised potassium salt of the mineral acid employed in step A is isolated, and (D) the resulting mother liquor is recycled. Potassium nitrate and potassium dihydrogen phosphate etc. are produced for use e.g. in fertilizer prodn. The technically simple process is for prodn. of technical-grade water-soluble potassium salts without the need to evaporate large amounts of water.