Electrode reaction of Pr(III) and coreduction of Pr(III) and Pb(II) on W electrode in eutectic LiCl-KCl

Abstract

The electrode reaction of Pr(III) and coreduction of Pb(II) and Pr(III) were studied on an inert W electrode in eutectic LiCl-KCl to extract Pr from molten salt. The electrode process kinetic of Pr(III) on W electrode was firstly explored employing cyclic voltammetry (CV) and Tafel technique, such as the diffusion coefficient of Pr(III) in eutectic LiCl-KCl and the exchange current density (j0) for Pr(III)/Pr(0) couple and the electrode reaction activation energy. Then, various electrochemical techniques were used to investigate the coreduction of Pb(II) and Pr(III). Four cathode current peaks ascribed to the formation of PrxPby intermetallic compounds were detected, which indicated that the Pr could deposit on pre-deposited Pb film, react with Pb, and form PrxPby intermetallic compounds. Furthermore, the electrolytic products formed by galvanostatic electrolysis were characterized by scanning electron microscopy coupled with energy dispersive X-ray diffraction, which illustrated the formation of PrPb3 intermetallic compound in LiCl-KCl-PbCl2-PrCl3 melt.