Dissolution of Rare Earth Elements from Nd Magnet Scraps Using Gas Electrodes in Molten Chlorides

Abstract

Here we study the dissolution of rare earth elements from Nd magnet scraps using Cl2 or O2 gas electrodes in order to achieve new rare earth recycle process. The anodic polarization of Nd magnet scraps and cathodic polarization of O2 gas electrodes were investigated in molten LiCl-KCl systems at 723 K. The anodic polarization was carried out by potentiostatic electrolysis of Nd magnet scraps electrode from 0.69-2.39 V(vs. Li+/Li) at every 0.050 V interval. The large anodic current was observed at 1.80-2.00 V due to anodic reaction of dissolution of rare earth elements. On the other hand, the cathodic polarization was carried out by potentiostatic electrolysis of O2 gas electrode using porous Ni from 1.20-2.30 V at every 0.10 V interval in a molten LiCl-KCl added Li2O(0.50 mol%) system. The large cathodic current was observed from 1.40-1.90 V due to cathodic reaction from O2 to O2-. It was possible to dissolve rare earth elements selectively from Nd magnet scraps using O2 gas electrodes.