Kinetic properties and electro-separation of U on binary liquid Ga–Al eutectic alloy cathode

The binary Ga–Al alloy cathode has been proven to be a prospective candidate for the separation of actinides over lanthanides (Lns) in the dry reprocessing. Therefore, in this work the electrochemical behaviors of U(III) on solid Al, liquid Ga and Ga–Al eutectic alloy cathodes were studied by cyclic voltammetry, and the kinetic properties of U(III)/U on these reactive cathodes were also investigated via electrochemical impedance spectroscopy technique in LiCl–KCl melts. The results showed that the exchange current density ( j 0 ) of U(III)/U on the Ga–Al eutectic alloy cathode is the largest, and followed the order: Ga–Al eutectic alloy > Ga > Al. Finally, U was electro-separated on the binary Ga–Al eutectic alloy cathode in a molten salt system containing U and representative Lns (La, Ce, Pr, Nd). The electrolysis products were validated to be Al 3 U and Ga 3 U according to XRD and SEM–EDS characterizations. The extraction rate of U was determined to be 88.3% via ICP-OES. This work is of theoretical guidance for high-temperature molten salt electro-separation of An over Ln. Graphical abstract