硝酸体系中Pu(Ⅲ)的Pt催化氧化

为了避免引入过多试剂,针对后处理Purex流程中将Pu(Ⅲ)氧化到Pu(Ⅳ)的调价过程,研究了一种新的催化氧化工艺。研究了在不同温度、酸度、肼浓度等条件下,硝酸体系中Pu(Ⅲ)的Pt催化氧化行为。结果表明:硝酸介质中Pu(Ⅲ)可以被Pt催化氧化为四价;在70℃条件下,当硝酸浓度大于3mol/L时,含支持还原剂肼的溶液中Pu(Ⅲ)的催化氧化调价可以很快实现,Pu(Ⅲ)氧化率大于99.9%;提高温度、加大酸度均有利于Pu(Ⅲ)的氧化;支持还原剂肼的量对其的催化氧化有一定的影响,肼的浓度升高,催化氧化的诱导期变长。

Pt-Catalyzed Oxidation of Pu( Ⅲ ) in Nitric Acid

In order to avoid introducing non-combustible reagents during the valence adjustments of Pu in the Purex process for nuclear fuel reprocessing,a new catalytic oxidation technology for conversion of Pu(Ⅲ) to Pu(Ⅳ) was studied in this paper.The influence of temperature,nitric acid concentration,and hydrazine concentration on the completeness and kinetics of Pt-catalyzed oxidation of Pu(Ⅲ) was investigated.The experimental results show that in the presence of a platinum gauze catalyst Pu(Ⅲ) in a hydrazine-containing solution can be quickly and almost quantitatively(>99.9%) oxidized to Pu(Ⅳ) at 70 ℃ and nitric acid concentrations higher than 3 mol/L.The increase of HNO3 concentration and elevation of temperature favores the oxidation of Pu(Ⅲ).The concentration of hydrazine also shows some influence:the higher the concentration of hydrazine is,the longer the induction period will be.