Electrorefining of Zirconium from Zircaloy-4 Cladding Hulls in LiCl-KCl Molten Salts

Abstract

Zr electrorefining from Zircaloy-4 cladding hulls is demonstrated in LiCl-KCl-ZrCl4 molten salts at 500 oC. Cyclic voltammetric measurement for pure Zr reveals that multiple reduction/oxidation reaction processes are involved due to various valence states of Zr in chloride baths. An insoluble reduction reaction is found to occur at -1.15 V vs. Ag/AgCl, where the both ZrCl and Zr metallic phases are produced. Almost similar voltammetric response is evident for Zircaloy-4 tube anode with additional reduction peaks associated with alloy elements. The purity of Zr recovered at -1.15 V from Zircaloy-4 tube appears to be 99.94 wt% by ICP-AES.