ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

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

Changqing Li, Mingyu Wu, and Yungang Li

Key Laboratory of Ministry of Education for Modern Metallurgy Technology, College of Metallurgy and Energy, ,North China University of Science and Technology, Tangshan, China

E-mail: liyungang59322@163.com

Received: 5 May 2020  Accepted: 17 July 2020

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 X_NaCl = 0.35, X_KCl = 0.35, and X_NaF = 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.

Keywords: Vanadium; Molten salt; Reduction mechanism; Electrocrystallization; Diffusion coefficient

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01293-0

Chemical Papers 75 (1) 227–235 (2021)