Preparation of Tantalum Powder from Ta₂O₅ by an Electrochemical Reduction in an LiCl–Li₂O Molten Salt System

Abstract

The electrochemical reduction of Ta₂O₅ in an LiCl–Li₂O molten salt system has been studied in an electrolytic cell with an integrated cathode assembly at 650°C. The integrated cathode assembly consists of an electric conductor, Ta₂O₅ and a porous magnesia membrane. The metallic tantalum is prepared successfully by the mechanism of an electrode reaction followed by a chemical reaction in the range of voltage between –2.47 V and –3.46 V. The chemical and physical properties of the metallic tantalum are influenced by the applied current related to the reaction rate. The XRD analysis indicates that the tantalum samples prepared at the applied current above 1.0 A have both of bcc and tetragonal structures. The particle size of those samples is similar to that of the fresh Ta₂O₅.