Selective leaching of vanadium from chromium residue intensified by electric field

•Alkaline leaching offered good selectivity for leaching vanadium.•Electro-oxidation was an efficient technology for leaching of vanadium.•Leaching process of vanadium was interpreted with shrinking core model.•The apparent activation energy of vanadium dissolution was 10.08 kJ/mol.

Electro-oxidation was an environmentally-friendly technology, which could enhance the leaching process of vanadium. A novel process was developed for the selective leaching of vanadium from residue. The effects of reaction temperature, alkali-to-residue mass ratio, contact time and current intensity on leaching of vanadium were studied. Results showed that under the optimal reaction conditions (reaction temperature of 90 °C, initial NaOH-to-residue mass ratio of 0.5:1 g/g, contact time of 120 min, liquid to solid ratio of 4 mL/g and current intensity of 1000 A/m2), leaching efficiency of vanadium could reach up to 91.7%. The kinetics study revealed that leaching process of vanadium from chromium residue intensified with electric field was interpreted with shrinking core model under chemical reaction control. The apparent activation energy of vanadium dissolution was 10.08 kJ/mol.