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Pandya, T. C.

doi:10.1023/a:1026665823572

Cited by 6 publications

(1 citation statement)

References 18 publications

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“…No variation was observed for the Debye−Waller factor σ 2 linked to the thermal agitation of the structure, and its value was found to be close to that of bulk ThO 2 , 53,54 confirming the very good crystallinity of the samples and the lack of significant amounts of structural defects. For the first shell Th−O 1 , the hydrothermal treatment or the temperature used had no significant impact.…”

Section: Resultsmentioning

confidence: 81%

Hydrothermal Conversion of Thorium Oxalate into ThO₂·nH₂O Oxide

et al. 2020

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Hydrothermal conversion of thorium oxalate, Th(C 2 O 4) 2 .nH 2 O, into thorium dioxide was explored through a multiparametric study, leading to some guidelines for the preparation of crystallized samples with the minimum amount of impurities. As the formation of the oxide appeared to be operated through the hydrolysis of Th 4+ after decomposition of oxalate fractions, pH values typically above 1 must be considered to recover a solid phase. Also, due to the high stability of the thorium oxalate precursor, hydrothermal treatments of more than 5 hours at a temperature above 220°C were required. All the ThO 2 .nH 2 O samples prepared presented amounts of residual carbon and water in the range of 0.2-0.3 wt.% and n  0.5, respectively. Combined FTIR, PXRD and EXAFS study showed that these impurities mainly consisted in carbonates trapped between elementary nanosized crystallites, rather than substituted directly in the lattice, which generated a tensile effect over the crystal lattice. The presence of carbonates at the surface of the elementary crystallites could also explain their tendency to self-assembly, leading to the formation of spherical aggregates. Hydrothermal conversion of oxalates could then find its place in different processes of the nuclear fuel cycle, where it will provide an interesting opportunity to set up dustless routes leading from ions in solution to dioxide powders in a limited number of steps.

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Section: Resultsmentioning

confidence: 81%