Study on Properties of TBP-HNO3 Complex Used for Direct Dissolution of Lanthanide and Actinide Oxides in Supercritical Fluid CO2
✍ Scribed by Wu-Hua Duan; Li-Yang Zhu; Shan Jing; Yong-Jun Zhu; Jing Chen
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 64 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0256-7660
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✦ Synopsis
The tri-n-butyl phosphate-nitric acid (TBP-HNO 3 ) complex prepared by contacting the pure TBP with the concentrated HNO 3 can be used for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide (SCF-CO 2 ). Properties of the TBP-HNO 3 complex have been studied. Experimental results showed that when the initial HNO 3 /TBP volume ratio was varied from 1∶7 to 5∶1, the concentration of HNO 3 in the TBP-HNO 3 complex changed from 1.95 to 5.89 mol/L, the [HNO 3 ]/[TBP] ratio of the TBP-HNO 3 complex changed from 0.61 to 2.22, and the content of H 2 O in the TBP-HNO 3 complex changed from 2.02% to 4.19%. All of the density, viscosity and surface tension of the TBP-HNO 3 complex changed with the concentration of HNO 3 in the complex, and were higher than those of the pure TBP. The protons of HNO 3 and H 2 O in the complex underwent rapid exchange to exhibit a singlet resonance peak in nuclear magnetic resonance spectra. When the TBP-HNO 3 complex was dissolved in a low dielectric constant solvent, small droplets of HNO 3 were formed that can be detected by NMR.