Diluent Effect on Extraction of Tin from HCI Solution with TBP

The present paper relates to the study on the diluent effect on the extraction of tin from hydrochloric acid solution with TBP. It is discovered that the effect of diluents on the extraction process of tin is related not only to their properties, but also to the technical conditions of the extraction process (HCl, (?) and (Sn~(4+)_(initial). Different diluents affect the distribution coefficients of tin D_((Sn)~(4+)). Under the same extraction conditions, D_((Sn)~(4+)) decreases with different diluents in the order of nitrobenzene, 1,2-dichloroethane, chlorobenzene, chloroform for polar diluents, and alkane (cyclohexane, n-hexane, n-heptane), aromatic hydrocarbon (benzene), halogenated hydrocarbon (tetrachloromethane) for nonpolar diluents. In the former case, it is explained by the dipole moment dielectric constant and solubility parameter of diluents, while in the latter case, by their polarizability and molar volume.