Incorporation mechanism of tungsten in W-Fe-Cr-V-bearing rutile
| Autor: | Stanislava Milovská, Christian Matthes, Juraj Majzlan, Jörg Göttlicher, Tomáš Mikuš, Martin Števko, Mária Čaplovičová, Ralph Bolanz, Christiane Rössler |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Bearing (mechanical) chemistry.chemical_element 02 engineering and technology Tungsten 010502 geochemistry & geophysics 021001 nanoscience & nanotechnology 01 natural sciences law.invention Geophysics chemistry Chemical engineering Geochemistry and Petrology law Rutile 0210 nano-technology Mechanism (sociology) 0105 earth and related environmental sciences |
| Zdroj: | American Mineralogist. 106:609-619 |
| ISSN: | 1945-3027 0003-004X |
| Popis: | Rutile is a common mineral in many types of ore deposits and can carry chemical or isotopic information about the ore formation. For closer understanding of this information, the mechanisms of incorporation of minor elements should be known. In this work, we have investigated natural rutile crystals with elevated concentrations of WO3 (up to 17.7 wt%), Cr2O3,tot (7.5), V2O3,tot (4.1), FeOtot (7.3), and other metals. X-ray absorption spectroscopy (XAS) of rutile at the Fe K, Cr K, V K, and W L1 and L3 edges shows that all cations are coordinated octahedrally. The average oxidation state of V is +3.8, and that of Cr is near +4. Shell-by-shell fitting of the W L3 EXAFS data shows that W resides in the rutile structure. Raman spectroscopy excludes the possibility of hydrogen as a charge-compensating species. High-resolution TEM and electron diffraction confirm this conclusion as the entire inspected area consists of rutile single crystal with variable amounts of metals other than Ti. Our results show that rutile or its precursors can be efficient vehicles for tungsten in sedimentary rocks, leading to their enrichment in W and possibly later fertility with respect to igneous ore deposits. Leucoxene, a nanocrystalline mixture of Ti and Fe oxides, is an especially suitable candidate for such a vehicle. |
| Databáze: | OpenAIRE |
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