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Hydrothermal Conversion of Thorium Oxalate into ThO2 · nH2O Oxide
- Source :
- Inorganic Chemistry, Inorganic Chemistry, In press, ⟨10.1021/acs.inorgchem.0c01633⟩, Inorganic Chemistry, American Chemical Society, In press, ⟨10.1021/acs.inorgchem.0c01633⟩
- Publication Year :
- 2020
- Publisher :
- HAL CCSD, 2020.
-
Abstract
- Hydrothermal conversion of thorium oxalate, Th(C2O4)2·nH2O, 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 Th4+ after decomposition of oxalate fractions, pH values typically above 1 must be considered to recover a solid phase. Also, because of the high stability of the thorium oxalate precursor, hydrothermal treatments of more than 5 h at a temperature above 220 °C were required. All the ThO2·nH2O samples prepared presented amounts of residual carbon and water in the range 0.2-0.3 wt % and n ≈ 0.5, respectively. A combined FTIR, PXRD, and EXAFS study showed that these impurities mainly consisted of 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.
- Subjects :
- Thorium dioxide
010405 organic chemistry
Metal ions in aqueous solution
Inorganic chemistry
Oxide
[CHIM.MATE]Chemical Sciences/Material chemistry
010402 general chemistry
01 natural sciences
7. Clean energy
Oxalate
Hydrothermal circulation
0104 chemical sciences
Inorganic Chemistry
Thorium oxalate
chemistry.chemical_compound
chemistry
13. Climate action
Impurity
Crystallite
Physical and Theoretical Chemistry
[CHIM.RADIO]Chemical Sciences/Radiochemistry
ComputingMilieux_MISCELLANEOUS
Subjects
Details
- Language :
- English
- ISSN :
- 00201669 and 1520510X
- Database :
- OpenAIRE
- Journal :
- Inorganic Chemistry, Inorganic Chemistry, In press, ⟨10.1021/acs.inorgchem.0c01633⟩, Inorganic Chemistry, American Chemical Society, In press, ⟨10.1021/acs.inorgchem.0c01633⟩
- Accession number :
- edsair.doi.dedup.....ee67545a2f2908c95526dd83fe709838