Published October 1987 | Version v1
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Investigation of the extraction kinetics of uranyl nitrate by tributyl phosphate: application of the single drop method in pulsed medium

Description

The investigation by the single drop technique of the uranium extraction kinetics in 3N nitric medium by tributyl phosphate diluted to 30 % in a hydrocarbon, revealed the composite nature of the transfer. The solvation of uranyl nitrate by TBP, assumed to be first order with respect to uranium, is the rate controlling mechanism when the continuous phase is aqueous whereas when the continuous phase is organic, the presence of a diffusional resistance was observed, more or less preponderant, depending on the degree of internal circulation of drops. Analysis in pulsed medium confirmed these observations and showed that the transfer kinetics is only accelerated by pulsation when the continuous phase is organic, for drops around 3mm in diameter only. The results of the analysis of the transfer mechanism serves to explain the influence of plate wettability by the dispersed phase on the transfer performance, observed during the extraction of uranium in a pulsed column

Abstract (French)

L'etude par la technique de la goutte unique de la cinetique de l'extraction de l'uranium en milieu nitrique 3N par le phosphate de tributyle dilue a 30 % dans un hydrocarbure a mis en evidence la nature mixte du transfert. La reaction de solvatation du nitrate d'uranyle par le TBP, supposee interfaciale et d'ordre un par rapport a l'uranium est limitante en phase aqueuse continue alors qu'en phase organique continue, la presence d'une resistance diffusionnelle plus ou moins preponderante selon le degre d'agitation interne des gouttes, a ete observee. L'etude en milieu pulse a confirme ces observations en precisant que la cinetique du transfert n'est acceleree par la pulsation qu'en phase organique continue, pour des gouttes de diametre voisin de 3 mm uniquement. Les resultats de cette analyse de la nature du transfert permettent d'expliquer l'influence de la mouillabilite des plateaux vis a vis de la phase dispersee sur les performances de transfert, observee lors de l'extraction de l'uranium en colonne pulsee

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Additional details

Additional titles

Original title (French)
Etude de la cinetique d'extraction du nitrate d'uranyle par le phosphate de tributyle: mise en oeuvre de la methode de la goutte unique en milieu pulse

Publishing Information

Imprint Pagination
164 p.
Report number
CEA-R--5414(rev.)