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Conclusions

The dissolution of solid Dy2O3 in molten CaCl2 was investigated by CSLM. Results illustrated that it dissolves only slightly within 2 h. The SEM results suggested that Dy2O3 is stable in molten CaCl2 at 1173 K (900 °C) and no other compounds (like e.g. DyOCl) were detected after quenching. This make Dy2O3 a good candidate for the direct electro-reduction to metal. The electrochemical behavior of dysprosium oxide at a solid molybdenum and a liquid tin cathode were investigated by cyclic voltammetry in a CaCl2 melt at 1173 K (900 °C). Two reduction steps can be noticed for Dy2O3 on a solid Mo electrode but only a single step was found on a liquid Sn electrode.

Acknowledgements The authors thank KU Leuven for financial support (IOF-KP Rare3 project). The authors thank Joris Van Dyck and Joop Van Deursen for their technical assistance.

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