Extraction of zirconium(IV) from hydrochloric acid solutions by tri-octylamine and neutral donors

Solvent extraction of Zr(IV) from aqueous HCl solutions by mixtures of TOA and different organophosphorous bases in carbontetrachloride solvent have been found to be always higher than that by any single extractant. Synergism has been observed in the range of 2.4–9.6M HCl. Although the species extracted with neutral donor alone seems to be ZrCl4·TOPO etc, with a mixture of extractants, however, the extracted species appears to be Q2ZrCl6·TOPO where Q is R3NH. The extraction has also been found to increase with increase in the concentration of amines and neutral donors. Enhancement of extraction has been explained by the formation of a complex adduct in organic phase. Synergistic coefficients and apparent formation constants of the complex adducts have also been calculated.