Computer modelling of the solvent extraction of iron by versatic acid from aluminium nitrate solutions

The development of a chemically based computer model of the extraction of ferric iron from concentrated aluminium nitrate solutions by Versatic 10 is outlined. The model uses previously determined equilibrium constants to calculate the distribution of iron in the various metal complexes present in the organic phase, together with empirical relationships for the pH changes occurring in the aqueous phase during extraction. A mean error of ±13% was found between computer predicted and experimentally determined organic phase iron concentrations for a four-stage counter-current extraction system. It is concluded that iron extraction by Versatic 10 is a technically feasible method of achieving aluminium nitrate with a sufficiently low iron content to enable the production of smelter grade alumina.