A novel synergistic extraction method for recovering vanadium (V) from high-acidity chloride leaching liquor

• V (V) was effectively separated from high-acidity chloride liquor with many ions.
• Synergistic coefficient of 3.26 was obtained by Aliquat 336–TBP extraction system.
• Over 90.0% of vanadium and almost no other cations were extracted in three stages.
• Vanadium stripping in one stage was above 92.0% and V2O5 product was prepared.
• Mechanism on V (V) extraction by mixed extractant was studied by FT-IR and UV–vis.

A selective synergistic extraction process for recovering vanadium (V) from the high-acidity chloride leaching liquor was proposed. Vanadium (V) extraction from the simulated high-acidity leaching liquor with numerous impurities using a mixed extractant consisting of tricaprylmethylammonium chloride (Aliquat 336) and tri-n-butyl phosphate (TBP) was studied while obvious synergism was found. According to synergistic enhancement coefficient and physical property of organic phase, the suitable extractant composition was the volume ratio of Aliquat 336 to TBP 1:4. The vanadium (V) extraction increased sharply as HCl concentration increased from 1.01 mol/L to 4.13 mol/L. Under the optimum extraction conditions (extractant concentration of 50 vol%, 1 min, 25–30 °C, and phase ratio (O/A) of 1:1), the vanadium extraction with three stages was above 90.0%. Almost no other impurity ions, such as Ca, Al, Mg, Cr, Ti, Mn, and Si, were co-extracted. Under the optimum stripping conditions, the vanadium stripping was above 92.0% in a single stage using water as the effective stripping reagent. High-quality V2O5 product was obtained after precipitation and calcination. The mechanism of vanadium (V) extraction by Aliquat 336–TBP mixed extractant was discussed based on the analysis of FT-IR and UV–vis spectra.