Extraction of uranium(Ⅵ) with di-(2-ethylhexyl) sulfoxide in toluene

The mechanism of extraction uranium(Ⅵ) with di(2-ethylhexyl) sulfoxide (DEHSO)from aqueous nitric acid media has been studied. The influence of the concentrations of nitricacid, cxtractant, salting-out agent, temperature and complex anions (C2O24-) on the distribution ratio was studied.

KINETIC STUDY ON THE EXTRACTION OF THALLIUM(Ⅲ) WITH DI(2-ETHYLHEXYL) SULFOXIDE FROM HYDROCHIORIC ACID MEDIA

The extraction of thallium (Ⅲ) with di (2-ethylhexyl) sulfoxide from hydrochloric acid media was studied by means of single-drop method.An extraction rate expression and the activation energysupport a mechanism,in which the ratelimiting step is HTlCl4+DEHSO(i) =HTlCl4DEHSO(i).

二(2—乙基己基)亚砜和磷酸三丁酯萃取铀、钍性能的比较

对二(2-乙基己基)亚砜(DEHSO)和磷酸三丁酯(TBP)萃取Th、U的性能进行了比较,研究了水相HNO_3浓度、萃取剂浓度、温度等因素对萃取Th、U的影响。DEHSO与U、Th和HNO_3形成的萃合物为UO_2(NO_3)_2·2DEHSO,Th(NO_3)_4·2DEHSO和HNO_3·DEHSO。在本实验浓度条件下测得萃取U、Th及NHO_3反应的平衡常数为14.9、0.027、0.13,U、Th萃取反应的热焓为-44.30和-42.50kJ/mol。同时试验了有机相中U(Ⅵ)和Th(Ⅳ)的反萃。

二(2-乙基己基)亚砜从硝酸介质中萃取铀(Ⅵ)的动力学研究

采用恒界面池法研究了二(2-乙基己基)亚砜(DEHSO)从稀硝酸介质中萃取铀(Ⅵ)的动力学行为。结果表明,在该条件下,DEHSO萃取铀(Ⅵ)的过程为扩散控制。硝酸根浓度是萃取过程重要动力学因子。萃取动力学方程为:R=K_fA[UO_2^+][H^+]^(-0.33)[NO_3^-]^(2·16)[DEH-SO]^(0.63)。萃取速率常数K_f为7.90×10^(-2)m·s^(-1)·l^(2.5)·mol^(-2.5)萃取表观活化能为0.9KJ·mol^(-1)。

HDEHP及其为载体的乳化液膜提取铀（VI）的动力学研究

用恒界面池法研究了二（２－乙基己基）磷酸（ＨＤＥＨＰ）－环己烷和以ＨＤＥＨＰ为载体的乳化液膜从硫酸介质中提取铀（ＶＩ）的动力学。通过分析水相组成、有机相或液膜组成、搅拌器转速和温度对提取速率的影响，分别得出了ＨＤＥＨＰ萃取和乳化液膜提取铀（ＶＩ）的速率规律。并对两种过程的提取机制进行了比较和讨论。研究表明：溶剂萃取过程属扩散控制；液膜提取过程属化学反应控制。