U(Ⅳ)-U(Ⅵ)同位素交换反应动力学研究 Ⅰ.Fe~(2+)对U(Ⅳ)-U(Ⅵ)同位素交换反应的催化作用

THE KINETIC STUDY ON U(IV)-U(VI) ISOTOPIC EXCHANGE REACTION Ⅰ.THE CATALYTIC EFFECT OF Fe~(21) IN THE U(IV)-U(VI) ISOTOPIC EXCHANGE REACTION

摘要: <正> 一、前言由于U(IV)-U(VI)同位素交换体系具有相当大的同位素效应和很好的稳定性,并且容易实现两相回流,这对于分离U同位素的工业应用都是十分有利的。但是,U(IV)-U(VI)同位素交换反应速度非常慢,常温下 H~+浓度为 1.0—4.0 mol/l时,速度常数为1.0×10~(-4)l~2/mol·s。因此要用 U(IV)-U(VI)交换体系浓缩铀同位素,必须研究 U(IV)-U(VI)交换反应动力学,找到加快交换反应的方法。

Abstract: The kinetics of the U(IV)-U(VI) isotopic exchange reaction was studiedwith ~(233)U as tracer in hydrochloric acid of high concentration. The catalytic effectof Fe~(2+) in the U(IV)-U(VI) isotopic exchange reaction was observed in thepresence of hydrochloric acid of high conentration. The exchange rate was foundto be accelerated by 10~2 times because of the addition of Fe~(2+). The activationenergy was calculated to be 73. 6 kJ/mol for the Fe~(2+) catalyzed U(IV)-U(VI)isotopic exchange reaction. This value is much smaller than that of 134.6 kJ/molwhich was found in the non-catalytic reaction.