Electrochemical behavior and extraction of Ce on liquid Sn cathode in LiF-LiCl eutectic

The electrochemical investigation of Ce(III) was carried out on W, Sn film and liquid Sn electrodes in LiF-LiCl eutectic by a variety of electrochemical methods. It was determined that Ce(III) was reduced to metallic Ce on W electrode via a one-step three-electron transfer, which was a reversible process controlled by diffusion. The diffusion coefficient of Ce(Ⅲ) in LiF-LiCl eutectic was estimated by CV and CP, while the diffusion activation energy was calculated to be 20.86 kJ mol −1 and 20.95 kJ mol −1 , respectively. The electrochemical behavior of Ce(Ⅲ) was studied on Sn film electrode by CV and OCP. Eight alloy compounds Ce x Sn were obtained due to the underpotential deposition of Ce on the pre-deposited Sn film electrode. The activities of Ce in Ce x Sn and standard Gibbs formation energies of Ce x Sn were evaluated, respectively. Moreover, on Sn film electrode, the electrochemical extraction of Ce was performed at −1.5 V. XRD, SEM and EDS results exhibited the formation of CeSn 3 and Ce 2 Sn 5 . On liquid Sn electrode, the reduction current of Ce appeared at about −1.2 V and reached a peak at about −1.4 V. The electrochemical extracting Ce was also conducted on liquid Sn electrode at −1.3 V and CeSn 3 was obtained. The extraction rates and efficiencies of Ce on liquid Sn electrode were estimated using ICP-AES at different durations. It was found that as the extraction proceeded, the extraction rate decreased, while the extraction efficiency increased. The extraction efficiency reached over 98 % after electrolysis for 10 h.