Co-reduction behaviors of lanthanum and aluminium ions in LiCl-KCl eutectic

Abstract

In this work, the co-reduction of La(III) and Al(III) ions on the Mo electrode was investigated in LiCl-KCl eutectic at 723-806K. Cyclic voltammetry (CV), square wave voltammetry (SWV), and open-circuit chronopotentiometry (OCP) techniques were employed to investigate the electrochemical behaviors of the co-reduction. From the CV and SWV results, the formation signals of five kinds of Al-La intermetallic compounds, which could be attributed to AlLa3, AlLa, Al2La, Al3La and Al11La3, were observed. The thermodynamic properties of La-Al intermetallic compounds in the temperature range of 723-806K were estimated by the OCP results. The changes of Gibbs energies, enthalpies and entropies of formation and the apparent standard potentials of La-Al intermetallic compounds were evaluated. Finally, potentiostatic electrolyses at 723K and galvanostatic electrolyses at 806K were carried out to confirm the co-reduction process, and the products obtained were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. It was found that the co-reduction products of Al11La3, Al3La and Al2La were obtained.