Electrochemical Reduction of Uranium Dioxide in LiCl–Li2O Melt

The electrochemical reduction of dense and porous pellets made from uranium dioxide in a molten LiCl electrolyte with Li2O content 1–2 wt.% was investigated. Electrolysis was conducted in a galvanostatic regime at cathode potential more positive by 0.05–0.15 V than the formation of a phase based on liquid lithium. It is shown that with such an electrolyzer uranium dioxide samples are almost completely reduced to metal after passing 160–180% of the theoretical amount of electricity. The metallized product has a porosity of 55–84%, depending on the density of the original tablets. This leads to significant capture of the salt electrolyte, whose removal by vacuum distillation is complicated by reduction of uranium dioxide. A great influence was noted on the stable operation of the cell of the anode compartment and, above all, the anode material. The best results were obtained using ceramic anodes made of nickel (II) oxide doped with lithium oxide.