Filimonova, Olga N, Wermeille, Didier and Kvashnina, Kristina O
(2023)
State of Ag in Pyrrhotite: Insights from X-ray Absorption Spectroscopy.
ACS EARTH AND SPACE CHEMISTRY, 7 (9).
pp. 1648-1660.
Abstract
Ag-bearing pyrrhotites Fe1-xS were synthesized by using the salt flux technique. The concentration of Ag in pyrrhotite reached 0.08 wt % at 540 °C and 1.3 wt % at 750-760 °C. The synthesized samples are divided into two groups according to the values of sulfur fugacity in the experimental system and the content of Fe (CFe) in pyrrhotite. In group (i) at low sulfur fugacity (log f(S2) ≈ −6.5, CFe > 48.8 at. %), Ag is disseminated in pyrrhotites in an “invisible” form but mostly concentrates on the grain boundaries of crystals as metallic rims. In group (ii) at high sulfur fugacity (log f(S2) ≈ −1.0, CFe < 48.8 at. %), Ag occurs as an invisible form disseminated in the pyrrhotite matrix together with the minor form of Ag-bearing submicron inclusions. Analysis of Ag K-edge XAS spectra recorded at ambient temperature revealed that the samples of group (i) contain a small fraction of the invisible Ag+ form, while the majority of Ag presents in pyrrhotite crystals as Ag°. The samples of group (ii) at a temperature of 750 °C contain the invisible form of Ag-Ag2+S-like clusters. The decrease in temperature leads to the partial decomposition of the invisible form and the appearance of the second (minor) form, Ag-bearing submicron inclusions. The predicted concentrations of Ag in pyrrhotite coincide with those from natural samples of various origins.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | synthetic minerals, silver, pyrrhotite, concentration, X-ray absorption spectroscopy, "invisible"silver, submicron inclusions, miscibility |
| Divisions: | Faculty of Science and Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 21 Sep 2023 10:34 |
| Last Modified: | 30 Sep 2023 09:17 |
| DOI: | 10.1021/acsearthspacechem.3c00002 |
| Open Access URL: | https://doi.org/10.1021/acsearthspacechem.3c00002 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3172915 |
Dimensions
Dimensions
