Direct electrochemical separation of uranium and lanthanides (Nd, Ce, La) from LiCl-KCl molten salt by bismuth and cadmium liquid metal electrodes

Pyroprocessing is efficient for recycling spent nuclear fuel, enabling the recovery of useful elements and minimizing waste. However, a key challenge is the difficulty in selectively separating U and Ln. This study investigates the feasibility of directly separating U and Ln elements (Nd, Ce, La) in LiCl-KCl molten salt using Bi and Cd as liquid metal electrodes. The electrochemical behaviors of U and Ln elements, as well as the formation of intermetallic compounds, were investigated using electrochemical measurements. The results revealed that in the presence of BiCl 3 , U formed intermetallic compounds with Bi. However, no such interactions were observed with CdCl 2 , indicating weaker interactions between U and Cd. For the Ln elements, Bi consistently formed intermetallic compounds with Nd, Ce, and La, whereas Cd showed stronger interactions with Nd and Ce than with La. Electrodeposition experiments demonstrated that U was deposited prior to the Ln elements in Bi and Cd media, with Ce and Nd preferentially deposited compared to La. Dissolution experiments showed that Ln elements dissolved before U in Bi, whereas in Cd, simultaneous dissolution of U and Ln was observed. These results demonstrate the feasibility of Bi as an effective medium for the electrochemical recovery of U and Ln. Conversely, Cd prevents their separation, supporting nuclear non-proliferation by maintaining U and Ln in a mixed state. • Bi enables selective U-Ln separation via intermetallic compounds. • Cd prevents U-Ln separation, aiding nuclear nonproliferation. • Novel electrochemical approach for U and Ln recovery. • Insights into U and Ln behavior in LiCl-KCl molten salt.