Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-26T08:10:03.645Z Has data issue: false hasContentIssue false

Hydroxylian pseudorutile derived from picroilmenite in the Murray Basin, southeastern Australia

Published online by Cambridge University Press:  05 July 2018

I. E. Grey*
Affiliation:
CSIRO Minerals, Box 312 Clayton South, Victoria, Australia 3169
C. Li
Affiliation:
CSIRO Minerals, Box 312 Clayton South, Victoria, Australia 3169
*

Abstract

Ilmenite concentrates obtained from heavy mineral deposits in the Murray Basin, southeastern Australia contain appreciable quantities (up to 10 wt.%) of an unusual hydrated Fe titanate mineral in the form of orange to red coloured translucent grains. The grains are weakly magnetic and have a low apparent density (<3.3 g cm–3) due to microprosity, which enables them to be easily concentrated in a pure state. Samples from different deposits have similar analyses of 67–69% TiO2, 8 –9% Fe2O3, 2–3% FeO, 11 –12% H2O and 8 –9% of intra-pore impurities, mainly SiO2 and Al2O3. The powder pattern for the mineral closely matches that for pseudorutile; having a hexagonal subcell with a = 2.844 (1) Å, c = 4.575 (1) Å. The idealized composition range of the Fe titanate, calculated from analyses and structure refinements, is [FeTi6O12(OH)3].3H2O to [FeTi6O11(OH)5].2H2O. The molecular water is nonstructural, probably adsorbed on the surfaces of nano-scale domains of the mineral. Electron microprobe and scanning electron microscopy studies provide evidence for formation of the mineral by replacement reactions acting on MgO-rich ferrian ilmenite grains. The mineral represents a distinct intermediate in the chemical weathering of ilmenite, having a pseudorutile-like structure but a leucoxene-like composition. It is unusual in not having undergone any recrystallization to phases such as rutile and anatase.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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

Bautsch, H.J., Rohde, G., Sedlacek, P. and Zedler, A. (1978 Kleberit – Ein neues eisen titan oxidmineral aus tert iaren sanden. Zei tschri f t Geologie Wissenschaften, 6, 661671.Google Scholar
Cullity, B.D. (1959 Elements of X-ray Diffraction . Addison-Wesley, Reading, USA.Google Scholar
Dammer, D., McDougall, I.M. and Chivas, A.R. (1999 Timing of weathering-induced alteration of manganese deposits in Western Australia: evidence from K/ Ar and 40Ar/39Ar dating. Economic Geology, 94, 87108.CrossRefGoogle Scholar
Dukino, R.D., England, B.M. and Kneeshaw, M. (2000 Phosphorus distribution in BIF-derived iron ores of Hamersley Province, Western Australia. Transactions of the Institution of Mining and Metallurgy (Section B: Applied Earth Science) , 109, B168176.Google Scholar
Dyadchenko, M.G. and Khatuntseva, A.Ya. (1960 Mineralogy and geochemistry of the weathering process in ilmenite. Doklady Akademii Nauk SSR, Earth Sciences, 132, 593597.Google Scholar
Dyadchenko, M.G. and Khatuntseva, A.Ya. (1961 Stadial alteration of ilmenite under supergene conditions. Voprosy Mineralogii Osadochnykh Obrazovanii, 5, 181209.Google Scholar
Farmer, V.C. (1974 The Layer Silicates. Pp. 331365 in: The Infrared Spectra of Minerals (Farmer, V.C., editor), Mineralogical Society Monograph 4. Mineralogical Society, London.CrossRefGoogle Scholar
Frost, M.T., Grey, I.E., Harrowfield, I.R. and Mason, K. (1983 The dependence of alumina and silica contents on the extent of alteration of weathered ilmenites from Western Australia. Mineralogical Magazine, 47, 201208.CrossRefGoogle Scholar
Grey, I.E. and Li, C. (2001 Low temperature roasting of ilmenite – phase chemistry and applications. The Australasian Institute of Mining and Metallurgy Proceedings 306 (2, 3542.Google Scholar
Grey, I.E. and Reid, A. F. (1975 The structure of pseudorutile and its role in the natural alteration of ilmenite. American Mineralogist, 60, 898906.Google Scholar
Grey, I.E. Li, C. and Watts, J.A. (1983 Hydrothermal synthesis of goethite-rutile intergrowth structures and their relationship to pseudorutile. American Mineralogist, 68, 981988.Google Scholar
Grey, I.E. Watts, J.A. and Bayliss, P. (1994 Mineralogical nomenclature: pseudorutile revalidated and neotype given. Mineralogical Magazine, 58, 597—60.CrossRefGoogle Scholar
Grey, I.E. MacRae, C. and Nicholson, T. (1999 Alteration of ilmenite in the Murray Basin – implications for processing. Australian Institute of Geoscientists Bulletin,, 26, 129134.Google Scholar
Hill, R.J. and Howard, C.J. (1986 A computer program for Rietveld analysis of . xed wavelength X-ray and neutron powder diffraction patterns . In: AAEC Report Number M112, Australian Atomic Energy Commission: Sydney, Australia.Google Scholar
Ignatiev, V.D. (1999 Solid phase mechanism of the ilmenite leucoxenisation. Lithology and Mineral Resources, 34, 184189.Google Scholar
Lasaga, A.C. (1990 Atomic treatment of mineral-water surface reactions. Pp. 1780 in: Mineral-Water Interface Geochemistry (Hochella, M.F. Jr. and White, A.F., editors). Reviews in Mineralogy, 23.CrossRefGoogle Scholar
Mineralogical Society of America, Washington, D.C. Putnis, A. (2002 Mineral replacement reactions: from macroscopic observations to microscopic mechanisms. Mineralogical Magazine, 66, 689708.CrossRefGoogle Scholar
Ruan, H.D. and Gilkes, R.J. (1995 Dehydroxylation of aluminous goethite: Unit cell dimensions, crystal size and surface area. Clays and Clay Minerals, 43, 196211.CrossRefGoogle Scholar
Shore, M. and Fowler, A.D. (1996 Oscillatory zoning in minerals: a common phenomenon. The Canadian Mineralogist, 34, 11111126.Google Scholar
Sinha, H.N. (1984 Hydrochloric acid leaching of ilmenite. Proceedings of Symposium on Extractive Metallurgy , Melbourne, November, 1984, pp. 163168. Published by the Australasian Institute of Mining and Metallurgy, Parkville.Google Scholar
Smellie, J.J.A. (1974 Formation of atoll garnets from the aureole of the Ardara pluton, Co. Donegal, Ireland. Mineralogical Magazine, 39, 878888.CrossRefGoogle Scholar
Teufer, G. and Temple, A.K. (1966 Pseudorutile – a new mineral intermediate between ilmenite and rutile in the alteration of ilmenite. Nature, 211, 179181.CrossRefGoogle Scholar