A study of cathode improvement for electro-deoxidation of Nb2O5 in a eutectic CaCl2-NaCl melt at 1073Â K

Significant improvement of cathode in the electro-deoxidation of solid Nb2O5 in a eutectic CaCl2-NaCl melt at 1073 K has been achieved by addition of carbon, calcium carbonate or calcium oxide powder to Nb2O5 powder. The powder mixtures were compacted into pellets and sintered, and then applied as the cathode. The results showed that the additives increased the oxygen vacancies and had an effect on particle size and surface area of the sintered solid Nb2O5 cathode. It was possible to accomplish the direct electrochemical reduction of solid Nb2O5 to metallic Nb rapidly by optimizing the amounts of carbon, calcium carbonate or calcium oxide added.