Electrochemical Behavior of UO₂F₂and Its Electrodeposition from UO₂F₂-FLiNaK Melt

Abstract

The electrochemical behavior of UO2F2 in LiF-NaF-KF (46.5-11.5-42 mol%, FLiNaK) melt on Pt electrode was investigated at 550°C by cyclic voltammetry (CV) and square wave voltammetry (SWV). UO2F2 was prepared by the reaction of UF4 powder and oxygen at 650°C, and ascertained by X-ray diffraction (XRD) and Raman spectroscopy. It was found that the reduction of UO22+ in FLiNaK exhibited two steps both with one exchanged electron: UO22+ + e− → UO2+ and UO2+ + e− → UO2, with the CV reduction peak at about 2.02 V and 1.49 V (vs. K+/K), respectively. Both of them were reversible and diffusion-controlled. By means of potentiostatic electrolysis, the product of UO2 was obtained and the separation ratio of uranium from UO2F2-FLiNaK melt was approximately 54.5% at 550°C, which were characterized by XRD and the inductively coupled plasma atomic emission spectrometer (ICP-AES).