Solvent extraction of scandium from chlorination system with EHPAEH

Abstract

The extraction of scandium from hydrochloric acid media with EHPAEH is investigated. Fe3+ in synthesized solution would reduce the purity of scandium, therefore, N235 is selected as extractant for separating Fe3+ and Sc3+. Experimental results indicated that separation factor βFe/Sc reached 5416.4 with the organic system consisting of 20 vol% trinoctylamine(N235), phase volume ratio(O/A) of 1:1, extraction stage of 3. Then mono(2-ethyl hexyl)-2-ethyl hexyl phosphonate(EHPAEH) is employed to extract Sc3+ from the leaching solution of Fe3+ free. With the organic phase containing 5 vol% EHPAEH, phase volume ratio O/A of 1:5, at pH 0.3, nearly 99% scandium is extracted. Finally, the scandium-loaded organic phase is stripped with 4.5N hydrochloric acid, under phase volume ratio of 1:1 at 65°C.