An Innovative Method to Increase Vanadium Extraction from Vanadium Slag by Increasing the Porosity of Roasted Pellet

Vanadium extraction from vanadium slag is significantly increased using only NaOH‐added pellet roasting to replace the traditional powder roasting previously. To solve some issues relevant to pellet holes, an innovation process to increase vanadium extraction from vanadium slag by increasing the porosity of roasted pellet is proposed presently. For the pellet added only with Na 2 CO 3 and roasted at 800 °C for 2 h, the melting point of Na 2 CO 3 , the pellet porosity, and the vanadium extraction are 851 °C, 6.3%, and 74%, respectively. For the roasted pellet with an optimal NaOH–Na 2 CO 3 additive having a mole ratio of NaOH/(NaOH + Na 2 CO 3 ) of 0.9, the melting point of additive, the pellet porosity, and the vanadium extraction are 300 °C, 29.6%, and 98.7%, respectively. It is confirmed that the vanadium extraction is proportional to the pellet porosity, maximum of which can be attained by optimizing mole ratio of NaOH to Na 2 CO 3 . Both the low melting point and the large alkaline of added NaOH–Na 2 CO 3 mixture are the two possible reasons resulting in the formation of pellet holes.