Electrochemical reduction of V2O5 in the (NaCl–KCl–NaF) molten salt

Abstract

The preparation of high purity metal vanadium is a challenging work, it is an important way to prepare vanadium tools by molten salt electrodeposition. Therefore, it is of great significance to study the electrochemical reduction mechanism and crystallization process of vanadium oxide in a specific molten salt. The electrochemical reduction mechanism of V2O5 in the molten salt of NaCl–KCl–NaF and its electrocrystallization process were investigated by voltammetry, chronopotentiometry, and chronoamperometry. The results indicate that the electrochemical reduction process of V2O5 is a reversible reaction with five electrons in one step and the generation of insoluble products, controlled by diffusion, with a reaction equation of VO3− + 5e− = V + 3O2−. The electrocrystallization process of V is an instantaneous hemispheroid three-dimensional nucleation process. When the temperature of the molten salt is 983 K, the mole fraction of each component in the salt is XNaCl = 0.35, XKCl = 0.35, and XNaF = 0.3. When the mass fraction of V2O5 is 5%, the active V ion exists in the form of VO3−, and its diffusion coefficient is 1.033 × 10−7 cm2 s−1.