Research on the Removal of Sodium from Vanadium Tailings by Calcification Roasting and NaOH Leaching

Vanadium tailings are a common solid waste in the vanadium industry. As they are rich in Fe, vanadium tailings could be a potential raw material for the blast furnace. However, the presence of approximately 4% Na2O in vanadium tailings is a major impediment to its return to the blast furnace. A novel method for removing sodium from vanadium tailings by calcification roasting and subsequent NaOH leaching was proposed in this work. The method demonstrated that calcification roasting of vanadium tailings can not only volatilize a part of sodium but also facilitate the dissolution of sodium during the subsequent NaOH leaching process. The thermodynamic analysis and behaviors of vanadium tailings during calcification roasting were systematically investigated. The transformation of sodium-containing phases in vanadium tailings during calcification roasting was studied. Further, the promoting effect of calcification roasting on sodium leaching by NaOH was clarified. The total removal efficiency of sodium was 80.37% under optimal conditions, and the residue obtained after sodium removal can be used as a raw material in the blast furnace process for in-plant recycling.