Investigation into the possibility of using a novel ionic liquid leaching method to obtain vanadium from vanadium slag

An environmentally friendly, novel method for extracting vanadium from slag with two imidazolium-based ionic liquids, namely1-butyl-3-methylimidazolium trifluoromethane sulfonate [Bmim+CF3SO3-], and 1-butyl-3-methyl-imidazolium hydrogen sulfate [Bmim+HSO4-], before and after magnetic separation, was proposed in this study. The effect of the type of ionic liquid, the concentration of ionic liquid, temperature and liquid to solid ratio were examined. The optimum experimental condition after examining these influential factors was found to be: ionic liquid [Bmim+HSO4-] 50% (v/v), a leaching temperature of 100 °C, and a liquid to solid ratio of 12 ml/g (12:1), at a leaching time of 90 min, with shaking speed of 250 rpm. The results indicated that a maximum vanadium extraction of 94.2% with 57.6% iron as an impurity could be achieved from the non-magnetic slag fraction. The kinetics of vanadium dissolution in 50% (v/v) [Bmim+HSO4-] was governed by a surface chemical reaction with an estimated Ea= 65.5 kJ/mol