Preparation of Niobium through Electrolysis of NbC_xO_y Soluble Anode

In this study, metallic niobium was produced by electrolysis in a NaCl-KCl melt using NbC x O y as a soluble anode. The anodic dissolution behavior of NbC x O y in the NaCl-KCl melt and the reduction mechanism of niobium ions were examined using cyclic voltammetry, linear sweep voltammetry, square wave voltammetry, electrochemical impedance spectroscopy, and chronopotentiometry. The results revealed that the electrode reduction process of niobium ion was Nb(Ⅴ) → Nb(Ⅲ) → Nb(Ⅰ) → Nb, with these reactions being diffusion-controlled. During successive multiturn scans, the reduction process of niobium ions favored the pathway of Nb(V) → Nb(III) → Nb. As the electrolytic voltage increased, the dissolution of niobium ions in NbC x O y also increased, with a tendency to oxidize into high-valence niobium ions. Constant-current electrolysis in a NaCl-KCl melt, using NbC x O y as the anode and Mo rods as the cathode resulted in the deposition of mainly metallic niobium on the Mo cathode, manifesting that NbC x O y can be used to extract metallic niobium. This study provides a theoretical foundation for the realization of a green and efficient extraction process for metallic niobium.