METHOD OF EXTRACTIVE SEPARATION OF RARE-EARTH ELEMENTS Russian patent published in 1995 - IPC

FIELD: rare-earth elements. SUBSTANCE: reextraction of rare-earth elements is carried out by stoichiometric quantity of nitric acid (concentration is 6-8.5 M) by two stages. Acidified water is fed on the last stage of reextraction unit (as 50-70% nitric acid for reextraction) where then in operation of aqueous phase concentrated nitric acid is added to the intermediate stage in order to increase its concentration up to 6-8.5 M. Concentrated solution of rare-earth element nitrates without acid is obtained from the first stage of reextraction unit where organic phase containing rare-earth elements is fed. Extraction of rare-earth elements is almost complete. EFFECT: decreased extractant loss, simplified process. 2 cl, 4 tbl