Technology Research on Clean Vanadium-extracting from Vanadium Slag by Blank Roasting

Aiming at the problems of high process cost and large amount of solid waste in existing vanadium extraction process from vanadium slag,a new process for preparing vanadium oxide from vanadium slag by blank roasting and carbonation leaching was proposed.The research mainly focused on the conditions of blank roasting and carbonation leaching.The results show that vanadium mainly exists in the form of Mn₂V₂O₇ and Mg₂V₂O₇ after blank roasting of vanadium slag at 860～900 ℃, and 90.49%～92.12% of vanadium leaching rate can be achieved under conditions as follows:concentration of NaHCO₃ 158 g/L、leaching temperature 95 ℃、leaching time 120 min;and V₂O₅ which satisfies the YB/T 5304—2017 standard can be obtained by adding sodium aluminate in the leachate for silicon removal and precipitating vanadium with NH₄HCO₃.The designed process route can realize the recycling of sodium and ammonia media,and has the characteristics of low process cost and less solid waste.