Electroextraction of neodymium from LiCl-KCl melt using binary liquid Ga–Al cathode

Abstract

The electrochemical behaviour of Nd(III) ion was investigated on inert W, active Ga and Ga–Al cathodes. It is established that the reduction of Nd(III) ion on the inert electrode is a consecutive two-step process while that on the active electrodes is a one-step process. The apparent standard potential of the Nd(III)/Nd redox couple at different temperatures was determined by open-circuit chronopotentiometry and semi-differential method, and the relationship between temperature and apparent standard potential was further discussed. The thermodynamic properties of Nd in Ga and Ga–Al electrodes such as activity coefficient and activity were evaluated via intermittent coulomb titration and temperature dependence test, and the effect of temperature on activity coefficient was verified. Finally, Nd was successfully extracted in form of alloy from molten salt by galvanostatic electrolysis, in which the current efficiency of 91.7% for the electroextraction indicates that the binary liquid Ga–Al electrode has favorable performance.