Scandium Extraction with Benzo-15-crown-5 from Neutral Nitrate–Trichloroacetate Solutions

Abstract

A systematic study for scandium extraction with benzo-15-crown-5 in chloroform from trichloroacetate solutions has been performed. The presence of free trichloroacetic acid in extraction system has been found to prevent scandium transfer into organic phase. Scandium is extracted from neutral trichloroacetate solutions as partially hydrolyzed trichloroacetate complexes, the extracted compound includes two crown ether molecules. The presence of nitrate anions has no effect on scandium distribution ratios and nitrate anion is not involved in extracted compound composition. Optimal process conditions for selective scandium recovery from concentrated solutions of rare-earth nitrates in the presence of lithium trichloroacetate with high separation factors (>100) on the use of B15C5 as extractant have been determined.