A METHOD FOR PURIFICATION OF CIRCULATING LEACHING SOLUTIONS FROM PHOSPHATES AND FLUORIDES

摘要

The present invention relates to a method for purification of acidic solutions of salts, in particularly those formed in the course of complex apatite processing yielding rare-earth metal (REM) concentrate from phosphorus, fluorine and alkali metals impurities comprising precipitation of phosphorus and fluorine in the form of calcium phosphates and fluorides and alkali metals in the form of silicofluorides of alkali metals. In some embodiments before the precipitation of calcium phosphates and fluorides and silicofluorides of alkali metals, acid is selectively extracted into an organic extractant, and after the precipitation of calcium phosphates and fluorides and silicofluorides of alkali metals the acid is may be re-extracted from the extractant into an aqueous solution. Methods allow for the removal of phosphorus, fluorine and alkali metals impurities and regeneration of the acid.