Preparation of metallic niobium from niobium pentoxide by an indirect electrochemical reduction in a LiCl-Li2O molten salt

The indirect electrolytic reduction of Nb2O5 has been investigated to produce metallic niobium powder in an electrolysis cell with a unique cathode assembly which consists of an electric conductor, solid oxide and magnesia membrane. The metallic niobium powder has been prepared by the mechanism of an electrode reaction followed by a chemical reaction in a LiCl-Li2O molten salt at 650 °C. The overall cathodic and the anodic reactions are the reduction of Nb2O5 and the formation of O2 gas, respectively. The XRD analysis suggests that the lithium niobates are fully converted to the metallic niobium by supplying 1.5-fold charges to the theoretical charges. The obtained results demonstrate that the electrolytic reduction technology by using a LiCl-Li2O molten salt is an efficient tool for preparing metallic niobium from Nb2O5.