Improving vanadium extraction from refractory stone coal by suspension roasting
(1. College of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China;
2. National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang 110819, China)
2. National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang 110819, China)
Abstract: An innovative suspension roasting-leaching technology in the atmosphere was proposed to improve the vanadium extraction from refractory stone coal. The leaching rate of vanadium was enhanced from 20% previously to 47.14% by present technology at a roasting temperature of 800 °C, a roasting time of 20 min, and a gas flow rate of 400 mL/min. Throughout the suspension roasting process, the surface of the stone coal gradually became rough and irregular. The specific surface area of the particles increased and the lamellar structure of the silicate minerals was destroyed, contributing to the release of vanadium. Meanwhile, the vanadium in the stone coal was oxidized to V(V) or V(IV). The results indicated that the leaching rate was improved owing to the release and transformation of vanadium in the suspension roasting.
Key words: stone coal; vanadium; suspension roasting; leaching; phase reconstruction; microstructure