Electrochemical Extraction of Ytterbium and Formation of Al–Yb Alloy from Yb2O3 Assisted by AlCl3 in LiCl–KCl Melt

Abstract

The work presents an electrochemical extraction of ytterbium and electrodeposition of Al–Yb alloy on W and Al electrodes in LiCl–KCl–AlCl3–Yb2O3 melt at 753 and 923 K. The cyclic voltammogram on a W electrode in LiCl–KCl–Yb2O3 (2 wt%) melt shows no obvious reduction wave except the reduction of Li(I) at –2.5 V. After adding AlCl3 to the system, the signals of the redox reaction of Yb(III)/Yb(II) and the formation of two kinds of Al–Yb intermetallic compounds were observed. However, only one kind of Al–Yb intermetallic compound forms on an Al electrode in LiCl–KCl–AlCl3–Yb2O3 melt. The measurement results of the dissolved ytterbium concentrations in LiCl–KCl–Yb2O3 and LiCl–KCl–AlCl3–Yb2O3 melt indicate that AlCl3 can effectively chloridize Yb2O3. X-ray diffraction (XRD) results of deposits obtained by potentiostatic electrolysis on Al electrodes suggest that Al3Yb and Al2Yb phases are formed. The bulk Al–Yb alloy, mainly containing Al3Yb phase, was prepared via galvanostatic electrolysis at a W electrode at 923 K. The microstructure and micro-zone chemical analysis of the bulk Al–Yb alloy were characterized by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS).