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@article{1874657,
author = {Plášil, Jakub and Steciuk, Gwladys and Majzlan, Juraj and Škoda, Radek and Filip, Jan and Petr, Martin and Kolařík, Jan and Klementová, Mariana and Bähre, Oliver and Kloss, Gert and Lapčák, Ladislav},
article_number = {5},
doi = {http://dx.doi.org/10.1021/acsearthspacechem.1c00386},
keywords = {3D electron diffraction; uraninite; weathering; supergene uranyl minerals; sorption; nanocrystalline},
language = {eng},
issn = {2472-3452},
journal = {ACS Earth and Space Chemistry},
title = {3D Electron Diffraction as a Powerful Tool to Study the Earliest Nanocrystalline Weathering Products: A Case Study of Uraninite Weathering},
url = {https://pubs.acs.org/doi/10.1021/acsearthspacechem.1c00386},
volume = {6},
year = {2022}
}
TY - JOUR
ID - 1874657
AU - Plášil, Jakub - Steciuk, Gwladys - Majzlan, Juraj - Škoda, Radek - Filip, Jan - Petr, Martin - Kolařík, Jan - Klementová, Mariana - Bähre, Oliver - Kloss, Gert - Lapčák, Ladislav
PY - 2022
TI - 3D Electron Diffraction as a Powerful Tool to Study the Earliest Nanocrystalline Weathering Products: A Case Study of Uraninite Weathering
JF - ACS Earth and Space Chemistry
VL - 6
IS - 5
SP - 1250-1258
EP - 1250-1258
PB - American Chemical Society
SN - 24723452
KW - 3D electron diffraction
KW - uraninite
KW - weathering
KW - supergene uranyl minerals
KW - sorption
KW - nanocrystalline
UR - https://pubs.acs.org/doi/10.1021/acsearthspacechem.1c00386
N2 - 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.
ER -
PLÁŠIL, Jakub, Gwladys STECIUK, Juraj MAJZLAN, Radek ŠKODA, Jan FILIP, Martin PETR, Jan KOLAŘÍK, Mariana KLEMENTOVÁ, Oliver BÄHRE, Gert KLOSS a Ladislav LAPČÁK. 3D Electron Diffraction as a Powerful Tool to Study the Earliest Nanocrystalline Weathering Products: A Case Study of Uraninite Weathering. \textit{ACS Earth and Space Chemistry}. American Chemical Society, 2022, roč.~6, č.~5, s.~1250-1258. ISSN~2472-3452. Dostupné z: https://dx.doi.org/10.1021/acsearthspacechem.1c00386.
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