Liquid Al assisted electrochemical extraction of lanthanum by formation of Al11La3 in chloride melts

Abstract In this work, different electrochemical measurements were employed to investigate the electrochemical behavior of La(III) on W and liquid aluminum electrodes, respectively. In LiCl–KCl melts, the diffusion coefficients of La(III) on W electrode at different experimental temperatures were determined by chronopotentiometry. The cyclic voltammetry results obtained on liquid aluminum electrode revealed only one pair of redox signal corresponding to the formation of Al–La intermetallic compound in LiCl–KCl–LaCl3 melts. The diffusion coefficient of La atom on the liquid Al–La alloy electrode was evaluated by anodic chronopotentiometry at 973 K. The electrochemical extraction of La was realized by galvanostatic electrolysis on a liquid aluminum electrode in LiCl–KCl–LaCl3 melts at 973 K, and the phases of Al11La3 and Al were identified by XRD. The SEM images disclosed needlelike precipitates in alloy, and the element La mainly distribute in the needlelike precipitates. After electrolysis, the extraction efficiency of element La was evaluated to be 99.4%, indicates that the electrochemical extraction of lanthanum with the help of liquid aluminum cathode is feasible in practice.