Study on Properties of TBP-HNO3 Complex Used for Direct Dissolution of Lanthanide and Actinide Oxides in Supercritical Fluid CO2

• Published in: Chinese journal of chemistry Vol. 25; no. 3; pp. 319 - 322
• Main Author: 段五华 朱礼洋 景山 朱永（贝睿） 陈靖
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2007; WILEY‐VCH Verlag
• Subjects: property; supercritical fluid carbon dioxide; TBP-HNO3 complex; TBP-硝酸配合物; 乏燃料; 直接溶解作用; 超临界二氧化碳流体; 锕类氧化物; 镧系氧化物
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.200790062

The tri-n-butyl phosphate-nitric acid （TBP-HNO3） complex prepared by contacting the pure TBP with the concentrated HNO3 can be used for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide （SCF-CO2）. Properties of the TBP-HNO3 complex have been studied. Experimental results showed that when the initial HNO3/TBP volume ratio was varied from 1 ： 7 to 5 ： 1, the concentration of HNO3 in the TBP-HNO3 complex changed from 1.95 to 5.89 mol/L, the [HNO3]/[TBP] ratio of the TBP-HNO3 complex changed from 0.61 to 2.22, and the content of H20 in the TBP-HNO3 complex changed from 2.02% to 4.19%. All of the density, viscosity and surface tension of the TBP-HNO3 complex changed with the concentration of HNO3 in the complex, and were higher than those of the pure TBE The protons of HNO3 and H2O in the complex underwent rapid exchange to exhibit a singlet resonance peak in nuclear magnetic resonance spectra. When the TBP-HNO3 complex was dissolved in a low dielectric constant solvent, small droplets of HNO3 were formed that can be detected by NMR.