Leaching vanadium from extracted vanadium residue of vanadium titanomagnetite

Vanadium was leached by composed leaching reagent of sulphuric acid, hydrofluoric acid and sodium hypochlorite from extracted vanadium residues of vanadium titanomagnetite. The process parameters, which impact on the vanadium leaching percent, such as reagent concentration, ratio of liquid to solid, temperature, leaching time, mineral granularity, were investigated. The results show that the vanadium leaching rate increases with the increase of reagent concentration, ratio of liquid to solid, temperature, leaching time and decreases with diminishment of the mineral granularity when the mineral granularity is less than 0.20 mm. The effect of sodium hypochlorite is smaller. When the extracted vanadium residues is leached with granular size of 0.15-0.25 mm, sulphuric acid concentration of 135 g/L, hydrofluoric acid concentration of 30 g/L, sodium hypochlorite dosage of 1.5%, ratio of liquid to solid of 6: 1, stirring velocity of 500 r/min at 90°C for 6 h, the leaching rate of vanadium is above 85%.