核化学与放射化学2025，Vol.47Issue(3)：235-241,7.DOI:10.7538/hhx.2025.47.03.0235
ThO2在HNO3中的回流溶解
Reflux Dissolution of Thorium Dioxide in Nitric Acid
卢宗慧 1于婷 1李斌 1何辉 1张烨1
作者信息
- 1. 中国原子能科学研究院放射化学研究所,北京 102413
- 折叠
摘要
Abstract
This study aims to investigate the reflux dissolution process of thorium dioxide in nitric acid,seeking an alternative to the current fluoride ion-dependent dissolution methods to prevent corrosion of stainless steel dissolvers and subsequent processing issues.By employing a reflux dissolution apparatus and utilizing nitric acid as the solvent,the effects of initial nitric acid concentration,temperature,and initial thorium ion concentration on the dissolution efficiency of thorium dioxide were systematically studied.The experimental results reveal that the apparent activation energy for the dissolution process of thorium dio-xide in nitric acid is 41.47 kJ/mol.An increase in initial nitric acid concentration from 9 mol/L to 12 mol/L corresponded with an increased dissolution rate of thorium dioxide,exhibiting an apparent order of about 3.However,a decline in the dissolution rate was observed when the initial nitric acid concentration surpassed 12 mol/L.Additionally,the initial thorium ion concentration was found to have a minimal impact on the dissolution rate.Further kinetic studies employing the shrinking core model indicate that the dissolution process of thorium dioxide is predominantly controlled by interfacial chemical reactions.Data fitting yield an apparent reaction rate constant k of(0.132±0.007)min-1.These findings provide significant theoretical support for optimizing the dissolution process in thorium-based fuel cycles and improving subsequent processing techniques.By systematically examining the impact of various factors on the dissolution of thorium dioxide,this research offers new insights and solutions for the dissolution process within thorium-based fuel cycles.Effective dissolution of thorium dioxide can be achieved without the use of fluoride ions by optimizing nitric acid concentration and controlling dissolution temperature,which is of considerable importance for the subsequent processing and application of thorium-based nuclear fuels.关键词
ThO2/回流溶解/动力学Key words
thorium dioxide/reflux dissolution/kinetic分类
核科学引用本文复制引用
卢宗慧,于婷,李斌,何辉,张烨..ThO2在HNO3中的回流溶解[J].核化学与放射化学,2025,47(3):235-241,7.
