Separation and recovery of vanadium from a sulfuric-acid leaching solution of stone coal by solvent extraction using trialkylamine

•Trialkylamine-N235 was used to recover of vanadium from acidic solution with massive impurities.•Various extraction effects were investigated.•The organic system had high efficiency to separate vanadium from massive impurities.•A process flow sheet for vanadium extraction was established.

Trialkylamine-N235, diluted with sulfonated kerosene containing tri-butyl phosphate, was used to separate vanadium and impurities as Fe, Al, Mg, K, Ca, P, and Si from a leaching solution generated by the sulfuric-acid leaching of vanadium-containing stone coal. Variations in aqueous pH exhibited good extraction of vanadium at an equilibrium pH of 1.6. Vanadium was successfully extracted by a three-stage countercurrent process using 20% N235 and 5% tri-butyl phosphate at an organic-to-aqueous (A/O) phase ratio of 2:1. The loaded organic was then scrubbed with 0.5 mol/L H2SO4, and most impurities were scrubbed by three-stage scrubbing. 1.0 mol/L NaOH was used to strip of vanadium from the scrubbed organic solution at an O/A phase ratio of 2:1, where >99% of vanadium was stripped in three stages. After regeneration by 1.0 mol/L H2SO4, the regenerated organic phase showed a good performance on vanadium extraction even after 5 cycles. Finally, a process flow sheet was established to recover of vanadium from a sulfuric-acid leaching solution of stone coal.