Solvent extraction of aluminium in the presence of cobalt, nickel and magnesium from sulphate solutions by Cyanex 272

The extraction and separation of aluminium from cobalt, nickel and magnesium sulphate solutions have been carried out using the organo-phosphinic extractant Cyanex 272. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of extraction pH at equilibrium, temperature, extractant concentration and organic to aqueous phase ratio. A statistically designed experiment was also carried out in order to study the stripping of the aluminium loaded Cyanex 272 organic phase by sulphuric acid solution. The number of stages required for both extraction and stripping processes of aluminium was also evaluated. The results of the continuous counter current, mini plant tests demonstrated the recovery of aluminium from cobalt, nickel and magnesium sulphate solution.