PROCEDURE FOR EXTRACTION OF RARE EARTH ELEMENTS FROM PHOSPHO-GYPSUM

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FIELD : metallurgy. SUBSTANCE : procedure consists in leaching phospho-gypsum with solution of sulphuric acid and in dissolving rare earth metals into solution. Prior to leaching phospho-gypsum is washed from phosphorus with water. Phosphorus is washed out in a closed cycle with dissolving of phosphorus into solution and its successive utilisation; it is run through a layer of carbonate waste and is returned to a reverse cycle of phospho-gypsum washing with water depleted of phosphorus. Phospho-gypsum is leached with solution of sulphuric acid at its concentration from 3 to 250 g/l. Rare earth metals are extracted from leaching solution by their concentration on cation exchanger, by their removing from cation exchanger with production of a commodity regenerate and by their return into the reverse cycle of leaching water solution depleted of rare earth elements. EFFECT : repeated utilisation of sulphuric acid solution at treatment of phospho-gypsum, obtaining maximum concentrated solution of rare earth metals cleared from impurities, reduced amount of phospho-gypsum wastes and their reclamation in building. 2 ex