Preparation of metallic niobium from niobium pentoxide by an indirect electrochemical reduction in a LiCl-Li_2O molten salt

摘要

The indirect electrolytic reduction of Nb_2O_5 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-Li_2O molten salt at 650 deg C. The overall cathodic and the anodic reactions are the reduction of Nb_2O_5 and the formation of O_2 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-Li_2O molten salt is an efficient tool for preparing metallic niobium from Nb_2O_5.