Distillation behavior of cadmium for U recovery from liquid cadmium cathode in pyroprocessing

Pyroprocessing has potential applications in recycling spent nuclear fuel. A key step in pyroprocessing, the distillation of Cd for U recovery, was examined using pure Cd, Cd–Bi alloy, Cd–Bi/LiCl–KCl, and Cd–U/LiCl–KCl. Pure Cd rapidly evaporated at above 400 °C, while test with the Cd–Bi alloy confirmed that the boiling of Cd is not an intrinsic property below 500 °C. The optimum heating condition for Cd distillation was determined (at the rate of 2 °C/min to 450 °C), based on surrogate test of Cd–Bi/LiCl–KCl. The simulated test for U recovery with Cd–U/LiCl–KCl exhibited 88.5% U recovery efficiency at the determined condition.