Thermodynamic study of uranium oxalate precipitation supersaturation ratio determination taking into account ideality deviation

A. Gutierrez-Chavida (1) , M. Bertrand (1) , G. Jouan (1) , E. Plasari (2) , H. Muhr (2) , J. Nos (3)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 UL - Université de Lorraine
3 ORANO

Oxalic precipitation is usually applied to process radioactive wastes or to recover actinides from a multicomponent solution. The driving force of precipitation reactions is given by supersaturation, which characterizes the deviation from the equilibrium state. Precipitation mechanisms, such as nucleation, crystal growth or agglomeration, are governed by supersaturation, which is therefore a crucial parameter to determine for process control. This work focuses on the description of a thermodynamic study of uranium (IV) oxalate precipitation in order, on the one hand, to develop a solubility model and, on the other hand, to estimate supersaturation ratio.

Keywords: Uranium; oxalate; supersaturation; activity coefficients; solubility

Domains: Nuclear Experiment [nucl-ex]; Nuclear Theory [nucl-th]

A. Gutierrez-Chavida, M. Bertrand, G. Jouan, E. Plasari, H. Muhr, et al.. Thermodynamic study of uranium oxalate precipitation supersaturation ratio determination taking into account ideality deviation. Cristal9, May 2019, Nancy, France. ⟨cea-02394046⟩