Solvent extraction equilibrium and modeling studies of manganese from sulfate solutions by a mixture of Cyanex 301 and TBP

• Mixture of Cyanex 301 and TBP shows synergism on the extraction of Mn(II).
• The highest synergistic effect was obtained at Cyanex 301 mole fraction of 0.6.
• The solvent extraction reaction was identified by applying a slope analysis method.
• The equilibrium constant of the solvent extraction reaction was estimated.
• Good agreement between the measured and calculated distribution ratios was obtained.

Studies on solvent extraction equilibrium of Mn(II) from sulfuric acid solutions with a mixture of Cyanex 301 and TBP have been carried out. The extraction of Mn(II) by Cyanex 301 was enhanced significantly by the addition of TBP at a Cyanex 301 mole fraction of 0.6 and the synergistic coefficient calculated was 1.16. Synergistic extraction reaction was identified on the basis of slope analysis and extracted species was proposed to be MnA2 · TBP. The solvent extraction equilibrium constant was estimated from the extraction data by considering the formation of complexes and activity coefficients of metal species in the aqueous phase. There was a good agreement between calculated distribution ratios of Mn(II) and experimentally measured values.