Solvent extraction equilibrium study of manganese(II) with Cyanex 302 in kerosene

The single-stage extraction of manganese(II) sulphate with Cyanex 302 in kerosene (O:A = 1:1) has been studied. The pH50 values are 5.75, 5.35, 5.20 and 4.15 for 0.025, 0.05, 0.07 and 0.1 M Cyanex 302, respectively. The mechanism of extraction and stoichiometries of metal-containing extracted species has been established on the basis of slope analysis and the distribution data has been used to calculate the extraction equilibrium constant. From the slope analysis data, the composition of the extracted species in the organic phase is proposed to be MnR2(RH)4. The temperature variation studies show that the extraction process is exothermic which is confirmed from the negative value of ∆H. The negative value of ∆S indicates strong complexation between Mn(II) and Cyanex 302.