SOLVENT-EXTRACTION SEPARATION STUDY OF TI(IV) FE(III) AND FE(II) FROM AQUEOUS-SOLUTIONS WITH DI-2-ETHYL HEXYL PHOSPHORIC-ACID IN BENZENE

The extraction of titanium(IV), iron(III) and iron(II) by di-2-ethyl hexyl phosphoric acid in benzene has been studied as a function of contact time, the concentration of the extractant in the organic phase, the temperature, etc. The study has been performed at different titanium and iron concentration ratios. It was observed that at around 0.35 M of sulfuric acid in the aqueous phase, the extraction of titanium is at a maximum. The three metal ions are extracted in the order: Ti(IV) > Fe(III) > Fe(II) with 0.2 M extractant and 0.35 M sulfuric acid solution, the separation factors β1 and β2 for Ti(IV)Fe(III) and TI(IV)Fe(II) respectively are found to be: β1= DTi(IV) DFe(III)≈60; β2= DTi(IV) DFe(II)≈500. As β2 is much greater than β1, the separation of titanium is facilitated if all the iron present is in the ferrous state. It has been observed that the separation of the metal ions is dependent on temperature of extraction, concentration of the extractant and acidity of the aqueous solution. Maximum extraction is shown at 50°C for Ti(IV) and Fe(II) and 40°C for Fe(III). © 1979.