AlCl3-aided extraction of praseodymium from Pr6O11 in LiCl–KCl eutectic melts

Abstract

Gibbs energy showed that AlCl3 can chloridize Pr6O11 and release Pr(III) ions in the LiCl–KCl–Pr6O11–AlCl3 melts. The co-reduction process of Al(III), Pr(III) and Li(I) ions was investigated in the LiCl–KCl–Pr6O11–AlCl3 melts. Three signals, corresponding to different Al–Pr intermetallic compounds, were observed by cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Potentiostatic and galvanostatic electrolysis were conducted to extract Pr element from LiCl–KCl eutectic melts by forming Al–Pr and Al–Li–Pr alloys, respectively. X-ray diffraction (XRD) indicated that both Al–Pr and Al–Li–Pr alloys comprised Al2Pr phase. The composition of Al–Li–Pr alloys was analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES). The proportion of Pr element in Al–Li–Pr alloys exceeded 40wt.% when the concentration of AlCl3 reached 8wt.% in the LiCl–KCl–Pr6O11(1wt.%) melts.