Study on a recovery of rare earth oxides from a LiCl–KCl–RECl 3 system

Abstract

Radioactive rare earth chlorides in waste LiCl–KCl molten salts have to be separated as a stable form to minimize waste volume and to achieve stable solidification. In this work, thermal behavior of rare earth chlorides (CeCl 3, GdCl 3, NdCl 3, PrCl 3) was investigated in an oxygen condition to recover rare earth oxides from a LiCl–KCl–RECl 3 system. The rare earth chlorides in the LiCl–KCl molten salts were smoothly converted to an oxychloride form at a higher temperature than 650 °C, except for CeCl 3. CeCl 3 was totally converted to an oxide from at a higher temperature than 450 °C. The rare earth oxychlorides (GdOCl, NdOCl, PrOCl) were effectively converted to oxide forms at a higher temperature than 1100 °C. It was confirmed that rare earth oxides can be recovered from a LiCl–KCl–RECl 3 system without impurity generation.