The thermal decomposition of studtite: analysis of the amorphous phase
| Autor: | Neil C. Hyatt, Nathan B.A. Thompson, Victoria L. Frankland, Martin C. Stennett, Matthew R. Gilbert, Joshua W. G. Bright, David Read |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Health Toxicology and Mutagenesis 010402 general chemistry 010502 geochemistry & geophysics 01 natural sciences Analytical Chemistry law.invention symbols.namesake chemistry.chemical_compound law Radiology Nuclear Medicine and imaging Calcination Spectroscopy 0105 earth and related environmental sciences Thermal decomposition Public Health Environmental and Occupational Health Uranyl Pollution XANES 0104 chemical sciences Amorphous solid Nuclear Energy and Engineering chemistry Studtite symbols Physical chemistry Raman spectroscopy Schoepite |
| Zdroj: | Journal of Radioanalytical and Nuclear Chemistry. 327:1335-1347 |
| ISSN: | 1588-2780 0236-5731 |
| DOI: | 10.1007/s10967-021-07611-4 |
| Popis: | Studtite is known to exist at the back-end of the nuclear fuel cycle as an intermediate phase formed in the reprocessing of spent nuclear fuel. In the thermal decomposition of studtite, an amorphous phase is obtained at calcination temperatures between 200 and 500 °C. This amorphous compound, referred to elsewhere in the literature as U2O7, has been characterised by analytical spectroscopic methods. The local structure of the amorphous compound has been found to contain uranyl bonding by X-ray absorption near edge (XANES), Fourier transform infrared and Raman spectroscopy. Changes in bond distances in the uranyl group are discussed with respect to studtite calcination temperature. The reaction of the amorphous compound with water to form metaschoepite is also discussed and compared with the structure of schoepite and metaschoepite by X-ray diffraction. A novel schematic reaction mechanism for the thermal decomposition of studtite is proposed. |
| Databáze: | OpenAIRE |
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