Highly efficient separation and extraction of vanadium from a multi-impurity leachate of vanadium shale using tri-n-octylmethylammonium chloride

An efficient separation and extraction method for the recovery of V (V) from a sulfuric acid leaching solution of vanadium shale was developed using the ionic liquid tri-n-octylmethylammonium chloride (TOMAC). In this study, the main factors affecting the extraction of vanadium using TOMAC were investigated. Under optimum conditions, including a TOMAC concentration of 20 vol%, initial aqueous phase pH of 1.8, phase ratio (O/A) of 1:10, and extraction time of 2 min, 98.1% of vanadium was separated by a three-stage extraction, while almost no other impurities were extracted. The V (V) present in the scrubbed organic phase could be quantitatively stripped using 1.0 mol/L NaOH. Moreover, the extraction mechanism using TOMAC was analyzed by Fourier transform infrared (FT-IR) spectroscopy as well as the slope method. The obtained results supported the existence of an anion exchange mechanism between the Cl- atoms of TOMAC and H2V10O284- (HV10O285-) within the extraction system.