2022
3D Electron Diffraction as a Powerful Tool to Study the Earliest Nanocrystalline Weathering Products: A Case Study of Uraninite Weathering
PLÁŠIL, Jakub; Gwladys STECIUK; Juraj MAJZLAN; Radek ŠKODA; Jan FILIP et. al.Základní údaje
Originální název
3D Electron Diffraction as a Powerful Tool to Study the Earliest Nanocrystalline Weathering Products: A Case Study of Uraninite Weathering
Autoři
PLÁŠIL, Jakub; Gwladys STECIUK; Juraj MAJZLAN; Radek ŠKODA; Jan FILIP; Martin PETR; Jan KOLAŘÍK; Mariana KLEMENTOVÁ; Oliver BÄHRE; Gert KLOSS a Ladislav LAPČÁK
Vydání
ACS Earth and Space Chemistry, American Chemical Society, 2022, 2472-3452
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10505 Geology
Stát vydavatele
Spojené státy
Utajení
není předmětem státního či obchodního tajemství
Odkazy
Impakt faktor
Impact factor: 3.400
Kód RIV
RIV/00216224:14310/22:00126262
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000806001000009
EID Scopus
2-s2.0-85130829215
Klíčová slova anglicky
3D electron diffraction; uraninite; weathering; supergene uranyl minerals; sorption; nanocrystalline
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 14. 7. 2022 11:58, Mgr. Marie Novosadová Šípková, DiS.
Anotace
V originále
Weathering of ore minerals proceeds through initialtransient products to many crystalline secondary minerals. However,the initial products are usually poorly characterized or overlookedbecause of their extremely small particle size, poor crystallinity, andchemical variability. Here, we document the strength of theprecession-assisted three-dimensional (3D) electron diffraction inthe characterization of such nanocrystalline phases in a case study onuraninite-sulfide weathering in Ja??chymov (Czech Republic). Theglassy, yellow-to-green near-amorphous coatings on the ore fragmentscontain at least two phases. 3D electron diffraction identifiedK0.268[(U6+O2)2O(OH)2.25](H2O)0.676as the dominant phase, yetunknown from nature, with fourmarierite topology of its uranylsheets. The minor phase was characterized as K-rich fourmarierite,but its crystallinity was too low for complete structure refinement.Glassy and brownish coatings occur on samples that are not rich in uraninite. They are mainly composed of schwertmannite, i.e.,iron oxides with structural sulfate and, in the case of our material, with a substantial amount of adsorbed uranium. This materialcontains up to 17 wt % of UO3,totaland 0.5-1.4 wt % of CuO according to the WDS study. Surprisingly, X-ray photoelectronspectroscopy showed that the adsorbed uranium is a mixture of U(IV) and U(VI), the reduced species formed most probably duringFe(II) oxidation to Fe(III) and coeval precipitation of schwertmannite. Hence, here, uraninite weathering produces initialnanocrystalline phases with fourmarierite-sheet topology. In the abundance of iron, schwertmannite forms instead and adsorbs muchuranium, both tetra- and hexavalent. This study demonstrates the power of 3D electron diffraction techniques, such as precessionelectron diffraction tomography, to study the alteration nanosized phases. Such nanocrystalline phases and minerals should beexpected in each weathering system and may impart significant control over the fate of metals and metalloids in such systems.
Návaznosti
| EF16_026/0008459, projekt VaV |
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