Electrochemical studies on the reduction behaviour of Th4+ in molten LiCl-KCl eutectic

The electrochemistry of Th4+ ions was studied in LiCl-KCl eutectic in the temperature range 698–803 K and compared with literature data. Various transient electrochemical techniques like cyclic voltammetry, chronopotentiometry, square-wave voltammetry were used to determine diffusion co-efficient of Th4+ and apparent standard electrode potential for Th4+/Th electrode process. The electrode kinetics of Th4+/Th couple was also investigated by convolution voltammetry and impedance spectroscopy. Based on the above studies, the reversibility of Th4+/Th couple was addressed. The feasibility of electrochemical separation of uranium and thorium in LiCl-KCl eutectic is also discussed in this paper. It was seen that the separation of U from Th matrix was difficult in molten LiCl-KCl using a solid rod cathode and suitable reactive electrodes need to be used for efficient separation.

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