Selective separation of Y and Nd with similar electrochemical properties by pulsed electrolysis on Sn electrode

Selective separation of Y and Nd from LiCl-KCl melt was systematically investigated on W and Sn electrodes by various electrochemical methods. The electrochemical properties of Y and Nd on W and Sn film electrodes were firstly analyzed and compared by cycle voltammetry (CV), square wave voltammetry (SWV), reverse chronopotentiometry (RCP), etc. The results indicate that the deposition potentials of Y and Nd on W electrode are very close, while the deposition potential difference could reach 0.15 V on Sn film electrode. The selective separation of Y and Nd was conducted by potentiostatic electrolysis (PE) on W electrode assisted by Sn(II), and the product is composed of Sn and NdSn3 phases. In addition, the electrochemical properties and kinetic parameter of Y and Nd on liquid Sn electrode were also studied. The results prove that Nd has a more positive deposition potential, larger exchange current density and smaller reaction activation energy than Y, illustrating that Nd is more easily extracted on liquid Sn electrode. Thus, PE and potentiostatic electrolysis + pulse potential electrolysis (PE + PPE) were used to separate Y and Nd on liquid Sn electrode. The results show that the application of PPE effectively reduced the extraction efficiency of Y from 16.75 ± 1.50 % to 8.36 ± 1.13 %, and increased the separation factor β from 4.98 ± 0.46 to 9.64 ± 0.58.