One-step electrochemical preparation of metallic vanadium from sodium metavanadate in molten chlorides

•The method about one-step electrochemical preparation of metallic vanadium from NaVO3 was proposed.•Metallic vanadium was obtained in the eutectic CaCl2–NaCl molten salt.•Reduction mechanism of NaVO3 to metallic vanadium was analyzed.

Conventionally, metallic vanadium is produced from vanadium pentoxide (V2O5). Sodium metavanadate (NaVO3) is an essential intermediate product for the V2O5 production. A novel environmentally friendly route for the metallic vanadium preparation from NaVO3 by molten salt electrolysis is proposed. In the NaCl molten salt, NaVO3 has a high solubility of 8.6 mol% (16.3 wt.%) at 1173 K and was easily electro-reduced to V2O3. However, V2O3 is almost insoluble in the NaCl molten salt, and thus can't be further electro-reduced to metallic vanadium. In the eutectic CaCl2–NaCl molten salt, NaVO3 was converted to CaV2O6. CaV2O4 as the intermediate product was produced during CaV2O6 electrolysis and can be dissolved into the eutectic CaCl2–NaCl molten salt. The dissolved CaV2O4 was further electro-reduced to metallic vanadium.