Leaching of Vanadium and Chromium from Vanadium-chromium Residue Intensified with H₂O₂

Vanadium and chromium in low valence are difficult to be leached in alkaline medium.For vanadium and chromium leaching,roasting with sodium salts might emit some poisonous gas and large amount of waste water,while roasting with calcium salts will consume much more energy.H₂O₂ as an oxidant was applied to intensify the leaching process of vanadium-chromium residue under alkaline condition.The effect of Na OH dosage,reaction temperature,dosage of H₂O₂,reaction time and stirring rate on the leaching efficiency of vanadium and chromium was investigated.The results indicate that increasing reaction temperature and extending reaction time can improve the leaching efficiency of vanadium and chromium.Vanadium is more easily to be oxidized and leached out in alkaline medium,even with low dosage of oxidant.The leaching ratio of vanadium is up to 94.30% with addition of H₂O₂. The leaching ratio of chromium is proportionally increased with increase of H₂O₂ dosage.Over 90.12% of chromium can be leached out at optimal conditions.H₂O₂ is a clean oxidant,which realizes an efficient and synchronous extraction of vanadium and chromium without bringing other impurities.This method is environmental-friendly with high reaction efficiency,and it could be applied as a new liquid oxidation technology.