Extraction of scandium from various media with triisoamyl phosphate: 3. Development of extractive refining of scandium

Abstract

Scandium refining to remove both more and less extractable impurity metals from hydrochloric acid solutions using semicountercurrent and countercurrent extraction with triisoamyl phosphate is modeled. A process for preparing high-purity scandium is developed, involving removal of more and less extractable impurity metals by semicountercurrent extraction and full countercurrent extraction, respectively, at a limited number of separation steps. From the initial scandium oxide (98% purity), 99.97% scandium oxide was prepared (99.995% purity with respect to REEs), i.e., the decontamination factors from both REEs and other impurity metals exceed 100.