A thermogravimetric study of the kinetics of hydrofluorination of uranium dioxide
| Autor: | Fabrice Patisson, Ch. Nicole, D. Ablitzer, J.-L. Houzelot |
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| Rok vydání: | 1996 |
| Předmět: |
Thermogravimetric analysis
Order of reaction Chemistry Applied Mathematics General Chemical Engineering Inorganic chemistry Uranium dioxide General Chemistry Activation energy Uranium tetrafluoride Hydrogen fluoride Industrial and Manufacturing Engineering chemistry.chemical_compound Reaction rate constant Pellet Nuclear chemistry |
| Zdroj: | Chemical Engineering Science. 51:5213-5222 |
| ISSN: | 0009-2509 |
| DOI: | 10.1016/s0009-2509(96)00271-0 |
| Popis: | The kinetics of the transformation of uranium dioxide to uranium tetrafluoride by hydrofluorination have been studied with the aid of thermogravimetric experiments performed at temperatures from 220 to 450°C in a nitrogen-diluted hydrogen fluoride atmosphere. Using the Grainy Pellet Model coupled with an optimization program, the rate controlling mechanisms and the characteristic kinetic parameters were determined. The reaction was found to be first order with respect to hydrogen fluoride, with an activation energy of 25 kJ/mol. It follows a chemical or intermediate regime, depending on the pellet diameter. Diffusion in the bulk of the small grains comprising the pellets is not rate-controlling. It is shown that the ideal pellet size in the industrial process is of the order of 1 mm. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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