TBP从盐酸溶液中萃取锡的稀释剂效应

TBP从盐酸溶液中萃取Sn~(4+)时,其稀释剂的影响不仅与稀释剂的性质有关,而且与盐酸浓度,萃取剂浓度,初始水相中锡的浓度等有关。只有[HCl]<6mol/L,[TBP]<40%,[Sn~(4+)]_(in)<1.5g/L时,才能排除这些因素的影响,因为这时各种稀释剂对Sn~(4+)的分配比D_(Sn~(4+))随这些因素的变化趋势相一致。在TBP-SnCl_4-HCl体系中,对于非极性类稀释剂,若按D_(Sn~(4+))的大小来排列,则烷烃类(环己烷、正己烷、正庚烷)>芳烃类(苯)>卤代烃类(四氯化碳),且可用稀释剂的极化率与摩尔体积等因素来解释;对于极性类有接受电子基团的稀释剂,则硝基苯>1,2-二氯乙烷>氯苯>氯仿,可用稀释剂的偶极矩、介电常数、溶解度参数或粘度等物性参数来解释其规律。

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.