Performance of the Liquid Cadmium Cathode Assembly for the Electrodeposition of U and Ce from LiCl-KCl Molten Salt

Abstract

A mesh-type assembly and stirrer assembly were developed to improve the performance of liquid cadmium cathodes for the electrodeposition of U and Ce from LiCl-KCl molten salt at 773 K. The thermodynamic basis for electrodepositing U and Ce was established through the calculation of equilibrium potentials and cyclic voltammograms, while also examining the co-deposition of Li. Thereafter, U and Ce electrodeposition was performed by galvanostatic electrolysis, and the current efficiency was determined. It was found that both assemblies effectively hampered the growth of U dendrites and Ce-Cd dendritic alloys. However, the utilization of the mesh-type assembly resulted in a greater current efficiency for U, with the maximum deposited amount attaining 7.7 wt% U/Cd without causing U dendrites formation. In contrast, the current efficiency for Ce was enhanced after using the stirrer assembly due to an improved diffusion flux of Ce ions. Finally, cathode deposits were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction, which revealed that disrupted fine U dendrites were randomly scattered in the Cd bulk, and that the CeCd 11 dendritic alloys were also damaged, leading to an increased atomic ratio of Ce to Cd at the Cd bottom.