Hydrometallurgical leaching process intensified by an electric field for converter vanadium slag

• Electric field was used to strengthen the oxidation process of low-valent vanadium.
• The mechanism of electro-oxidation hydrometallurgical leaching process was explored.
• The optimal conditions for vanadium extraction were determined.
• The leaching rate of vanadium reached 93.67% under the optimum conditions.

Low-valent vanadium in the insufficient oxidation roasting process of sodium salt reduces vanadium leaching yield. Therefore, the electro-oxidation leaching method was investigated to strengthen the oxidation process of low-valent vanadium. The mechanism of the electro-oxidation hydrometallurgical leaching process was examined along with the electrochemical performance of the reaction system through X-ray diffraction, scanning electron microscopy, ultraviolet, and ultraviolet–visible diffuse reflectance spectroscopy. Results showed that low-valent vanadium can be oxidized effectively under an electric field in the leaching process. The leaching yield of vanadium reached 93.67% under the optimum conditions, including a current density of 1000 A/m2, a liquid-to-solid ratio of 4:1 ml/g, a temperature of 80 °C, and a leaching time of 40 min. This percentage is 3.73% higher than that attained under the same conditions without an electric field. Meanwhile, the vanadium content in slag decreased from 7.15% to 0.98%.