METHOD OF SELECTIVELY REMOVING ADSORBED CALCIUM AND MAGNESIUM FROM CATION EXCHANGE RESINS

摘要

Adsorbed calcium is selectively removed from cation exchange resins in the presence of adsorbed magnesium by eluting the resin with aqueous sulfuric acid saturated with CaSO4 and undersaturated with MgSO4 to obtain a solution supersaturated with CaSO4 from which the CaSO4 can be readily precipitated. The magnesium is subsequently removed from the resin by eluting with aqueous sulfuric acid, such as 20-70% H2SO4. The method is advantageously used in the regeneration of cation exchange resins, such as the loaded resins used for treatment of phosphate rock-derived phosphoric acid.