Balan Etienne, De Villiers J.P.R., Eeckhout S.G., Glatzel P., Toplis M. J., Fritsch Emmanuel, Allard T., Galoisy L., Calas G. (2006). The oxidation state of vanadium in titanomagnetite from layered basic intrusions. American Mineralogist, 91 (5-6), p. 953-956. ISSN 0003-004X.
Titre du document
The oxidation state of vanadium in titanomagnetite from layered basic intrusions
Balan Etienne, De Villiers J.P.R., Eeckhout S.G., Glatzel P., Toplis M. J., Fritsch Emmanuel, Allard T., Galoisy L., Calas G.
Source
American Mineralogist, 2006,
91 (5-6), p. 953-956 ISSN 0003-004X
The redox conditions prevailing during the formation of vanadiferous titanomagnetites from three layered intrusions (Bushveld; Koillismaa; Skaergaard) have been estimated from the valence state of vanadium using synchrotron X-ray absorption near edge structure spectroscopy (XANES). Using a high energy-resolution X-ray emission spectrometer, we show that vanadium occurs mostly as V3+, with minor V4+. The most concentrated samples (up to 2.4 Wt% V2O3) contain approximately 10% of vanadium as V4+. Both V3+ and V4+ occur in the octahedral site of the spinel structure. Considering the low magnetite/melt V4+ partition coefficients, this suggests that vanadium ores crystallized under specific oxidizing conditions.
