Electrochemical Deposition with Redox Replacement of Lanthanum with Uranium in Molten LiCl-KCl

Abstract

Electrochemical recovery of dilute concentrations of actinides from spent nuclear fuel would reduce the longevity of storing high-level nuclear waste. Electrochemical deposition with redox replacement (EDRR) is used in a molten salt medium for the selective electrochemical recovery of uranium in the presence of excess concentrations of lanthanum. In each EDRR cycle, after a short electrodeposition pulse, the deposited lanthanum is spontaneously replaced by uranium at open circuit. After repeated cycles, uranium metal was obtained on a tungsten electrode immersed in a LiCl-KCl melt that contained 1 wt% lanthanum chloride—0.15 wt% uranium (IV) chloride. Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) analysis revealed uranium particles approximately 0.5−1 μm with well-defined rectangular shapes; and with 20–60 times more uranium recovered on the surface of the electrode than lanthanum.