The oxidation of UF 4 in FLiNaK melt and its electrolysis

The oxidation of UF4 in LiF–NaF–KF (FLiNaK) melt with oxygen sparging was conducted at 823 K and analyzed by in situ infrared spectrometer, UV–Vis absorption spectrometer, and other characterizations with thermodynamic calculations, indicating UF4 was converted to UO2F2 with the following reaction mechanism: 2UF4 (l) + O2(g) + 2H2O(g) = 2UO2F2(l) + 4HF(g). Cyclic voltammetry measurements showed that the reduction of UO22+ in oxidized melt exhibited two steps both with one exchanged electron: UO22+ + e− → UO2+ and UO2+ + e− → UO2. By potentiostatic electrolysis, the product of UO2 was obtained with nanoscale triangular sheet structure.