Efficient and environment-friendly vanadium (V) extraction from vanadium shale leachate using tri-n-octylmethylammonium chloride

In this work, an efficient and environmentally friendly method for recovering V (V) from vanadium shale leachate using an ionic liquid, tri-n-octylmethylammonium chloride (TOMAC), was proposed. The main factors affecting the extraction and stripping of vanadium using TOMAC were studied. A significant quantity (93.18%) of vanadium was extracted with almost no impurities under the following conditions: the concentration of TOMAC was 20 vol%; the concentration of 2-octanol as the phase modifier was 15 vol%; the phase ratio (O/A) was 1:10. More than 90% of vanadium in the loaded organic phase could be stripped quantitatively using a mixed solution of 0.8 mol/L NaOH and 1.2 mol/L NaCl. The stripping and regeneration of the loaded organic phase could be carried out in one step. Meanwhile, the anion exchange mechanism of extraction and stripping was analyzed by Fourier transform infrared (FT-IR) spectroscopy. Moreover, the organic phase stripped by the NaOH-NaCl synergistic stripping system maintained a relatively high extraction efficiency (> 90%) even across many cycles, which indicated that the developed system is environmentally friendly and efficient for the recovery of vanadium.