Recovery of vanadium from leach solutions of vanadium slag using solvent extraction with N235

Leach solutions of vanadium (V) slag was generated from (NH4)(2)SO4 (AS) roasting and water leaching process. After separating titanium (Ti) from the solutions, the remaining liquor contains a large amount of V and iron (Fe). In this study, a system composed of trioctyl tertiary amine (N235) and sulfonated kerosene was used to separate V; moreover, the feasibility, mechanism, and energy evaluation of this system were also investigated. The results indicated that the single-stage V extraction rate was 86.35% using 40% N235 (v/v) and 60% sulfonated kerosene, an initial pH of 1.23, an organic/aqueous phase ratio (O/A) of 1.5:1, a temperature of 298.15 K, and an extraction time of 1 min. Based on McCabe-Thiele analysis, over 99% of the V was extracted by three-stage countercurrent extraction. Using the slope method and Fourier transform infrared (FT-IR) spectroscopy, the V extracted by N235 was proposed to exist as [(R3NH)(4)center dot H2V10O28]. Using 1.4 mol/L ammonia water, over 90% of the V could be stripped. The effects of the impurities Si, Ca, Al, Mg, and Mn on V recovery were negligible. A preliminary material and energy calculation (MEC) indicated that 113.64 kg V2O5 could be recovered from 1000 kg raw V slag using 5.57 x 10(6) kJ of heat and 974.45 kWh of electricity.