Study on extracting vanadium by no additive roasting-acid leaching from a illite-type vanadium-containing stone coal

The illite-type stone coal containing vanadium from the Shangluo region of Shaanxi province is selected as raw materials.Vanadium is extracted by no additive roasting-acid leaching, the effects of roasting time, roasting time, and leaching temperature, leaching time, sulfuric acid concentration, liquid to ratio are investigated.The results show that roasting temperature has a significant influence on leaching rate of vanadium recovery.It is difficult to leach vanadium at the condition of lower and higher roasting temperature, and only when roasting temperature is within proper temperature range, the leaching effect of vanadium is better.It is feasible to extract vanadium from illite-type stone coal containing vanadium by additive-free roasting process,under the conditions that roasting temperature remains at 850 ℃ for 2 h, the sulfuric acid concentration is 5%,the leaching temperature remains at 90 ℃ for 1 h, and the liquid-solid ratio of 4∶1 mL/g, the leaching rate of vanadium is 72.53%.The results of SEM analysis show that the main reasons for the loss of vanadium are the produced vanadium inclusions in the roasting process and the vanadium which is not released from the illite.