Enrichment of rare earth and alkaline-earth elements by countercurrent electromigration in room temperature molten salts

Abstract

For the recovery of the electrochemically negative elements such as the rare earth and the alkaline-earth elements, it is important to develop the recycle process which has less potential hazards. For this purpose, we have proposed the novel environmental harmonization process using the room temperature molten salts substituted for the high-temperature pyrometallurgical processes. The countercurrent electromigration methods using ammonium imide type room temperature molten salts have been performed as an efficient enrichment process. The results allow us to conclude that the trivalent ions are drastically enriched at the anode compared with the divalent ions and the trivalent cations were separated from the divalent ones. In addition, the relative differences among rare earth cations have calculated from the quantitative data, which were compared with the data in high-temperature molten salts and discussed.