Vanadium Extraction from Korean Vanadiferous Titanomagnetite Ore Using Alkali Roasting: Evaluation of Optimal Conditions and Leaching Rate

The extraction process of vanadium from vanadiferous titanomagnetite ore deposited in Korea was investigated by combining alkali roasting and water leaching processes. The effect of Na 2 CO 3 addition on the efficiency with which the vanadium could be leached was investigated along with an X-ray diffraction analysis. When more than 30-wt% Na 2 CO 3 was added at 1273 K, a vanadium leaching efficiency of approximately 70% was achieved. The minimum alkali-roasting temperature was determined to be 1273 K with the addition of 30-wt% Na 2 CO 3 . Thermodynamic calculations revealed that the formation of the liquidus phase of Na 2 CO 3 enhanced the reaction between the vanadium in the concentrate and sodium, resulting in a higher leaching efficiency for vanadium being attained. The thermodynamic calculation results were indirectly supported by the characteristic temperature determination through hot-stage microscope analysis. After 30 min of thermal treatment, a leaching efficiency for vanadium of 75% was achieved, which remained constant as the thermal treatment time was increased. Finally, the effects of the leaching time and temperature on the efficiency with which vanadium and other impurities, namely, aluminum, silicon, and sodium, could be leached was analyzed by varying the leaching time. A higher leaching efficiency was attained at higher temperatures. The leaching rate of vanadium decreased considerably after 10–20 min and subsequently remained almost constant.