Uranium recovery via electrochemical deposition with a liquid zinc cathode followed by electrochemical oxidation of rare earth metals

Uranium recovery with electrochemical deposition followed by selective oxidation of rare earth (RE) metals was examined to confirm the feasibility of liquid Zn cathode and figure out the behavior of RE dissolution. U was used as a surrogate for U/transuranic (TRU) elements in this study. About 1.6 wt% UCl3, 2.9 wt% NdCl3 and 3.1 wt% CeCl3 was dissolved into the LiCl-KCl eutectic, and the U, Nd, and Ce was co-deposited into a liquid Zn cathode. About 3.3 g of U/RE alloy was successfully consolidated by subsequent removal of the Zn with the distillation. U was segregated and agglomerated with each other in a matrix alloy consisting of Nd and Ce, confirming the co-deposition of RE along with U. The U/RE alloy was electrochemically oxidized to remove the RE, applying a constant voltage of -1.7 V (vs. Ag/AgCl) at the anode. Approximately 2.2 g of final product in a granular shape was ultimately obtained after the subsequent removal of residual salts. Characterization revealed that the concentration of U was larger than that of the REs, even though a large amount of REs still remained, confirming the selective dissolution of REs. The results suggest a new method, i.e., electrochemical deposition followed by selective oxidation of RE, to recover U/TRU from the LiCl-KCl salt using a liquid Zn cathode. (C) 2019 Elsevier B.V. All rights reserved.