萃取过程中的盐析效应

以磷酸三丁酯萃取富马酸和从盐酸溶液中苹取Sn~(4+),三烷基氧化磷革取苹果酸、琥珀酸,二丁基亚矾从天然磷矿的盐酸分解液中萃取盐酸和磷酸为例,进行了萃取过程盐析效应的研究。提出了盐析剂浓度对被萃物分配比或萃取率经验公式,并用文献中的数据对此经验公式进行了检验,计算值与实验值吻合较好。

Salting-Out Effect in Extraction Process

The effects of salting-out agents on the extraction of Sn~(4+) and fumaric acid with TBP, malic acid and succinic acid with TRPO as well as HCl and H_3PO_4 with DBSO are discussed. For the salting-out agents used in Sn~(4+) extraction, the effect is in the following order; AlCl_3>CaCl_2>NaCl>NH_4Cl>KGl. The distribution coefficients(D_(MA), D(SA) and D_(FA)) of malic acid, succinic acid and fumaric acid increase with increasing concentration of NaCl; D_(MA) and D_(SA) decrease while D_(FA) increases with increasing concentration of NaNO_3; D_(MA) and D_(FA) decrease with increasing concentration of Na_2SO_4. The higher the concentration of CaCl_2 in the leach liquor of phosphorite by hydrochloric acid, the higher the distribution coefficients of HCl and H_3PO_4 in extraction. An empirical formula has been proposed, by which the effect of concentration of salting-out agents on distribution coefficient(D_2)and percentage extraction (E_1)can be calculated. Where n is equal to 3/2 when the anion of salting-out agents is the same as that of the solute. The calculated values are in close agreement with experimental results for TBP-UO_2(NO_3)_2-HNO_3 system as reference.