Electrochemical behavior of neodymium chloride on aluminium and cadmium cathodes in LiCI-KCI eutectic melt

Molten salt electrorefining is proposed as a viable method for reprocessing spent metallic fuel. It is necessary to have an insight on the behaviour of actinides and lanthanides at the electrodes during the process. In the present study, the electrode reaction of NdCl₃ on aluminum and cadmium cathodes in LiCI-KCI eutectic melt using electrochemical methods such as cyclic voltammetry and open circuit potentiometry have been investigated. Reduction of NdCl₃ on these electrodes takes place at much positive potential than on an inert electrode. Neodymium is stabilized as intermetallic compounds AI₁₁Nd₃ and Cd₁₁Nd on aluminum and cadmium cathodes respectively. The apparent standard electrode potentials for Nd(Ill)/Nd(AI) and Nd(Ill)/Nd(Cd) were estimated in the temperature range 698-773 K from the cyclic voltammetry data. The Gibbs energy of formation for the respective intermetallic compound, the excess Gibbs energy and the activity coefficients of neodymium in aluminum and cadmium were estimated from the open circuit potential measurement. (author)