METHOD OF REMOVING AND CRYSTALLIZING CATION RESIN ADSORBED CALCIUM AND MAGNESIUM

摘要

An improved method is provided for regenerating cation exchange resin loaded with metal ion impurities from wet process phosphoric acid. A regenerant solution is used composed of a mixture of ammonium sulfate and sulfuric acid in predetermined proportions which are maintained during recycle of the regenerant. This solution is preferably formed from anhydrous ammonia and sulfuric acid. Calcium and magnesium sulfates are selectively crystallized from the regenerant solution in the form of readily filterable crystals.