Extraction equilibrium of manganese(II) from sulfate solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene

The distribution ratios of manganese(II) extracted from an aqueous sulfate medium by di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in kerosene were studied at 25 °C. The extraction equilibria are influenced by the total extractant concentration in the organic phase, equilibrium pH values and total sulfate concentration in the aqueous phase. The distribution data have been analyzed both graphically and numerically. The results show that the species extracted into the organic phase have compositions of MnR2(HR)2¯ and MnR2(HR)3¯. The stability constants of MnSO4 and HSO4− in the sulfate solutions were also estimated from the extraction data.