Separation of Neodymium and Dysprosium by Molten Salt Electrolysis Using an Alloy Diaphragm

As a part of our ongoing study on a new rare-earth elements recycling process using molten salts and alloy diaphragms, selective permeation of Dy through an alloy diaphragm is investigated in LiCl-KCl eutectic melts containing NdCl3 and DyCl3 at 450 degrees C. In this process, the permeation of rare-earth elements is carried out via the following three steps: (a) cathodic reduction of rare-earth ions to form alloys on one side of the diaphragm, (b) diffusion of rare-earth atoms in the diaphragm, and (c) anodic oxidation of rare-earth atoms to ions on the other side of the diaphragm. A preliminary experiment reveals that Dy selectively permeates the diaphragm under an appropriate condition.