Production of High-Purity Niobium by Carbon Reduction Smelting and Electron Beam Melting

This paper deals with a two-stage heat treatment method in which carbon reduction smelting of niobium oxides and electron beam melting-refining of niobium are combined to produce high-purity niobium. In carbon reduction smelting, Ar plasma arc was used as a heat source, and the relations of carbon mixing mole ratio to Nb₂O₅ (C/Nb₂O₅) to the amounts of oxygen and carbon contents remaining in the reduced niobium were investigated, together with the reduction conditions for enhancing the degassing effect in the subsequent electron-beam melting stage. In the two-stage method, the recovery of niobium was examined as well as the possibility of removing or decreasing metal impurities.