Modeling of liquid-liquid extraction of vanadium with primary amine N1923 in H2SO4 medium

This paper deals with a systematic thermodynamic study on the liquid-liquid extraction of vanadium from aqueous solution (0.001-0.1 mol/kg) using primary amine N1923 (0.004-0.3 mol/kg). Suitable and practical thermodynamic models (Pitzer-Pitzer and Pitzer-Margules) were improved and verified for the first time. Firstly, the Pitzer parameters were correlated based on solid-liquid equilibrium data, and then employed as the initial values in regression progress. Finally, all the interaction parameters (βaq0, βaq1, βRV,RVorg, βR,RVorg, βR,Rorg, ARV,Rorg, Atol,RVorg and Atol,Rorg) were regressed. Liquid-liquid equilibrium data were predicted using those parameters and compared to the experimental results, which confirmed the reliability and suitability of these models for the present system. Furthermore, these models provided excellent predictions of the effect of the initial amine molality and pH value on the extraction, showing great promise for industrial applications.