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用二(2-乙基己基)磷酸和三-正辛基氧瞵煤油溶液从浓磷酸水溶液中协同萃取铀,促进了对有机相中 U(Ⅵ)所形成的络合物类型的研究。考察了在形成络合物时水相中磷酸浓度的作用,这种作用严重地影响萃取过程。已经发现 U(Ⅵ)是以 UO_2X_2(HX)_2mTOPO 的形式被萃取入有机相,式中 m≤1.取决于 TOPO 浓度。增加温度也使萃取系数减小。对温度影响的研究导出了该过程热焓的变化值。在磷酸介质中亚铁使 U(Ⅵ)还原成 U(Ⅳ),而 U(Ⅳ)没有协同效应,这与 U(Ⅳ)络合物在配位上是饱和的事实相符。此外,该协萃体系甚至在浓的磷酸溶液中仍得到相当好的萃取系数。
The synergistic extraction of uranium from concentrated phosphoric acid aqueous solution with di (2-ethylhexyl) phosphoric acid and tri-n-octylene oxide kerosene promoted the study of the complex types of U (Ⅵ) in the organic phase. The effect of the concentration of phosphoric acid in the aqueous phase on the formation of the complex was examined and this effect severely affected the extraction process. It has been found that U (VI) is extracted into the organic phase in the form of UO_2X_2 (HX) _2mTOPO where m≤1, depending on the TOPO concentration. Increasing the temperature also decreases the extraction factor. The effect on temperature leads to a change in the enthalpy of the process. The reduction of U (Ⅵ) to U (Ⅳ) by ferrous iron in phosphoric acid medium, while U (Ⅳ) has no synergistic effect, is consistent with the fact that U (Ⅳ) complex is saturated in coordination. In addition, the synergistic extraction system still yields a fairly good extraction factor even in concentrated phosphoric acid solutions.