TBP从盐酸溶液中萃取锡的研究

EXTRACTION OF TIN FROM HCl SOLUTION BY TBP

本文报道了TBP从盐酸溶液中萃取锡时各种因素对D_(Sn^(4+))的影响。分别讨论了极性稀释剂与非极性释稀剂对萃取过程的影响。研究了五种常用无机盐对萃取过程的盐析作用,其强弱次序为AlCl_3>CaCl_2>NaCl>NH_4Cl>KCl;提出了一简单有效的计算盐析剂浓度对分配比或萃取率影响的经验公式,并用文献中的数据进行了检验,结果令人满意。其它无机酸的加入对Sn^(4+)的萃取性能有较大的影响;加入HNO_3、H_3PO_4使萃取分配比下降,H_2SO_4使分配比迅速增加。实验中比较了Sn^(4+)与Sn^(2+)的萃取性能,发现TBP萃取Sn^(4+)的能力比Sn^(2+)略大。解释了萃取过程中三相出现的原因。

The present paper studies the extraction of tin from hydrochloric acid by TBP. The extraction ability of Sn^(4+) and Sn^(2+) by TBP is compared experimentally, and Sn^(4+) appears a little better ability than Sn^(2+). It is discovered that if kerosene is selected as the diluent for TBP, the third phase appears When MIBK is tile modifier and the concentration of hydrochloric acid is higher than 7mol/l, the third phase will also appear, which may be the misability of MIBK in the concentrated acid solution. Different diluents affect the distribution coefficients of tin. Under the same conditions, for nonpolar diluents, D_(Sn^(4+)) is in the following order: alkane>aromatic>hydrohalic hydrocarbon; for polar diluents, D_(Sn^(4+)) decreases with the decrease of their dielectric constant, dipole moment and solubility parameter. The effect of salting-out agents on D_(Sn^(4+)) is in the followiog order: AlCl_3>CaCl_2>NaCl>NH_4Cl>KCl. An experiential equation is proposed with which the effect of salting-out agents concentration on D_(Sn^(4+)) can be calculated. Other inorganic acids also influence the extraction of tin from HCl solution by TBP. D_(Sn^(4+)) decreases with increasing concentration of HNO_3 and H_3PO_4, but increases with that of H_2SO_4.