Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-19T11:22:19.483Z Has data issue: false hasContentIssue false
  • English
  • Français

The thermal behaviour of an Fe-rich illite

Published online by Cambridge University Press:  09 July 2018

E. Murad  and
U. Wagner
E. Murad
Affiliation:
Bayerisches Geologisches Landesamt, Concordiastraße 28, D-96049 Bamberg, Germany
U. Wagner
Affiliation:
Physik-Department El5, Technische Universität München, D-85747 Garching, Germany
Get access Rights & Permissions [Opens in a new window]

Abstract

The phase changes that took place upon heating an Fe-rich illite (OECD #5) to 1300°C in an oxidizing atmosphere were studied by a variety of mineralogical techniques. Infrared spectra, showing the stepwise dehydroxylation of the illite, showed good agreement with variations in sample colour and Mössbauer spectra. Dehydroxylation did not lead to noticeable variations in X-ray powder diffraction patterns until the structural breakdown of illite and formation of new phases at about 900°C Mössbauer spectroscopy proved to be very sensitive to all changes induced by heating, showing the disappearance of Fe2+ at 250°C, the gradual dehydroxylation between about 350 and 900°C, and characteristic features of the products formed at higher temperatures, e.g. the formation of hematite as the illite structure breaks down and the subsequent disappearance of hematite due to the incorporation of Fe in glass above 1200°C. The formation of hematite in clusters large enough to order magnetically at room temperature was first observed in the sample heated to 900°C, whereas at 4.2 K, significant proportions of a magnetically ordered phase could already be identified in the sample heated to 650°C.

Type
Research Article
Information
Clay Minerals , Volume 31 , Issue 1 , March 1996 , pp. 45 - 52
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barron, V. & Torrent, J. (1986) Use of the Kubelka-Munk theory to study the influence of iron oxides on soil colour. J. Soil Sci. 37, 499–510.Google Scholar
Dyar, M.D. (1985) A review of Mössbauer data on inorganic glasses: the effects of composition on iron valency and coordination. Am. Miner. 70, 304–316.Google Scholar
Farmer, V.C. (1974) The layer silicates. Pp. 331-363 in: The ln(rared Spectra of Minerals (Farmer, V.C., editor). Mineralogical Society, London.Google Scholar
Guggenheim, S., CHANG Y-H. & Koster Van Groos, A.F. (1987) Muscovite dehydroxylation: high-temperature studies. Am. Miner. 72, 537–550.Google Scholar
Heller-Kallai, L. ∼ ROZENSON 1. (1980) Dehydroxylation of dioctahedral phyllosilicates. Clays Clay Miner. 28, 355–368.Google Scholar
Mackenzie, K.J.D., Brown, I.W.M., Cardme, C.M. & Meinhold, R.H. (1987) The thermal reactions of muscovite studied by high-resolution solid-state 29-Si and 27-A1 NMR. J. Mater. Sci. 22, 2645–2654.Google Scholar
Malatih, N., Purl, S.P. & Saraswat, I.P. (1971) Mössbauer studies of iron in illite and montmorillonite. II. Thermal treatment. J. Phys. Soc. Japan 31, 117–122.Google Scholar
Michael, P.J. & Mcwmnnm, W.R. (1989) Mössbauer and ESR studies of the thermochemistry of illite and montmorillonite. Polyhedron, 8, 2709–2718.Google Scholar
Murad, E. & Wagner, U. (1994a) The Mössbauer spectrum of illite. Clay Miner. 29, 1–I0.Google Scholar
Murad, E. & Wagner, U. (1994b) Mössbauer study of pure illite and its firing products. Hyperfine Interact. 91, 685–688.Google Scholar
Olphen, H. VAN & Fripiat, J.J. (1979) Data Handbook for Clay Materials and Other Non-Metallic Minerals. Pergamon Press, Oxford.Google Scholar
Stanjek, H. & Friedricu, R. (1986) The determination of layer charge by curve-fitting of Lorentz- and polarization-corrected X-ray diagrams. Clay Miner. 21, 183–190.CrossRefGoogle Scholar
Velde, B. (1978) Infrared spectra of synthetic micas in the series muscovite-MgA1 celadonite. Am. Miner. 63, 343–349.Google Scholar