Kinetics of simultaneous stripping of U(VI) and nitric acid from tri-n-butyl phosphate

• Published in: Progress in nuclear energy (New series) 2021-04, Vol.134, p.103678, Article 103678
• Main Authors: Murali, Remya, Ganesh, S., Desigan, N., Augustine, Elizabeth, Rajeev, R., Pandey, N.K.
• Format: Article
• Language: English
• Subjects: Dodecane; Heat transfer; Impellers; Interfacial reaction; Kinetic control regime; Kinetics; Mass transfer; Nitric acid; Nitric oxide; Rate constants; Reaction kinetics; Stripping; Stripping kinetics of U(VI); Uranium
• ISSN: 0149-1970; 1878-4224
• DOI: 10.1016/j.pnucene.2021.103678

The study of kinetics of simultaneous stripping of uranium U(VI) and nitric acid (HNO3) from the loaded tri-n-butyl phosphate (TBP) in n-dodecane (n-DD) phase was carried out using dilute nitric acid in a constant interfacial area stirred cell (Lewis Cell). The influence of various parameters like rotational speed of impeller, temperature and aqueous to organic phase volume ratio on the kinetics of stripping was investigated. The objective of the present work was to identify the location of reaction and regime of reaction for the simultaneous stripping of U(VI) and nitric acid based on the systematic experimental investigations. A comprehensive kinetic model has been developed and validated with the experimental data to determine the rate constants and the mass transfer coefficients. From the present study, it was concluded that the location of reaction is at the interface between aqueous and organic phases and the reaction regime was found to be kinetic controlled regime for the stripping of U(VI) and diffusion controlled regime for the stripping of nitric acid. [Display omitted] •Kinetic study of simultaneous stripping of uranium and nitric acid from loaded TBP/NDD was carried out in Lewis cell.•Effect of rotational speed of impeller, temperature and aqueous to organic phase volume ratio on the kinetics was studied.•Development and validation of kinetic model with the experimental data to determine kinetic and diffusion parameters.•The location of reaction is found to be at the interface between aqueous and organic phases.•Reaction regime was found to be kinetic controlled for the stripping of U(VI) and diffusion controlled for nitric acid.