High-efficiency extraction of europium from LiCl-KCl molten salt using liquid SnZn alloy electrode

With the growing demand for europium (Eu) in advanced fields such as opto-electronics and nuclear technology, developing efficient extraction methods has become increasingly crucial. This paper focuses on the electro-extraction of europium in LiCl-KCl molten salt, employing Sn and Sn Zn electrodes. The electrochemical behavior of Eu(III) on the Sn electrode in the molten salt system was investigated through cyclic voltammetry (CV), square wave voltammetry (SWV), chronoamperometry (CP), and open circuit chronopotentiometry (OCP) techniques. The results reveal that the reduction of Eu(III) to Eu occurs Eu(III) + e −  → Eu(II) and Eu(II) + 2e −  + mSn → EuSn m . Furthermore, the electrochemical behaviors of LiCl-KCl-ZnCl 2 -SnCl 2 on the W electrode revealed a peak for the Zn-Sn-Eu alloy. The exchange current density and reaction activation energy of Eu(II)/Eu were calculated on the liquid Sn and Sn Zn electrode through the polarization curve. Subsequently, constant current electrolysis was carried out using Sn and Sn Zn electrodes to extract Eu, and the extraction effect of Eu using a Zn Sn electrode is far superior to that using a Sn electrode. The extracted products were characterized via Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS) and X-Ray Diffraction (XRD), and the concentration of Eu(III) in molten salt at different times was detected by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and the extraction efficiency under different conditions was calculated and the valence state changes of Eu during electrolysis on different electrodes were analyzed using X-ray photoelectron spectroscopy (XPS).