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Iron ore sinter in the analytical transmission electron microscope

Published online by Cambridge University Press:  05 July 2018

R. Mulvaney
R. Mulvaney*
Affiliation:
Department of Metallurgy, University of Sheffield, Mappin Street, Sheffield, S1 3JD *
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Abstract

Iron ore sinters prepared for the blast furnaces at Scunthorpe, Humberside, comprise iron oxides bound in a matrix of aluminium- and silicon-rich calcium ferrites with some calcium orthosilicate and a residual silicate glass. A super-silicon-deficient clinopyroxene with up to half of the Si in the chain replaced by Fe3+ and Al3+ precipitates from the glass in some areas. The iron oxides are principally magnetite and hematite with some wüstite in highly reduced areas. The calcium orthosilicate has been previously reported as the mineral larnite, β-Ca2SiO4. This study found a range of Fe for Ca substitution and three polymorphs were recognised: the range Ca2SiO4 to Ca1.85Fe0.15SiO4 has the structure of larnite; the range Ca1.85Fe0.15SiO4 to Ca1.6Fe0.4SiO4 has the structure of bredigite, α′-Ca2SiO4. Iron substitution beyond this, and up to a maximum of about Ca1.5Fe0.5SiO4, was not recognisable as a polymorph of Ca2SiO4, but an orthorhombic cell is tentatively proposed. The complex ferrite SFCA (silico-ferrite of Ca and Al) is variable in composition, but has a minimum of about 3 wt. % Al2O3 and contains 20 wt. % CaO and SiO2 with a Ca: Si ion ratio of about 2 : 1. A C-face centred monoclinic cell has been deduced: a 15.70, b 9.70, c 8.48 Å; β 105°30′. The Al appears critical for the formation of SFCA in sinter; without it, a eutectic of magnetite and bredigite precipitates in preference.

Keywords

iron ore sinterselectron microscopyferrites.
Type
Electron Microscopy in Mineralogy and Petrology
Information
Mineralogical Magazine , Volume 51 , Issue 359 , March 1987 , pp. 61 - 69
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1987

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Footnotes

*

Present address: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET.

References

Ahsan, S.N., Mukherjee, T., and Whiteman, J.A. (1983) lronmakin9 and Steelmaking,, 10, 54–65. Google Scholar
Bowen, N.L., Schairer, J.F., and Posnjak, E. (1933) Am. J. Sci., 25, 273-97.CrossRefGoogle Scholar
Bredig, M.A. (1950) J. Am. Ceram. Soc., 33, 188-92.CrossRefGoogle Scholar
Bridge, T.E. (1966) Am. Mineral., 51, 1766-7.Google Scholar
Cliff, G. and Lorimer, G.W. (1975) J. Microscopy,, 103, 203-7.CrossRefGoogle Scholar
Coheur, P. (1969) J. Iron Steel Inst., 207, 1291-7.Google Scholar
Deer, W.A., Howie, R.A., and Zussman, J. (1962) Rock Forming Minerals,, 3, Longman, London.Google Scholar
Dowty, E. and Clarke, J.R. (1973) Am. Mineral., 58, 23O-42.Google Scholar
Dyson, D.J. and Juckes, L.M. (1972) Mineral. Mag., 38, 872-7.CrossRefGoogle Scholar
Hancart, J., Leroy, V., and Bragard, A. (1967) CNRM Metall. Rev., 11, 3-7.Google Scholar
Hughes, H., Roos, P., and Goldring, D.C. (1967) Mineral. Mag., 36, 280-91.Google Scholar
Ireland, B.J. (1982) Transmission electron microscopy of authigenic clay minerals. Unpubl. PhD thesis, University of Sheffield.Google Scholar
Lister, D.H. and Glasser, F.P. (1967) Trans. Brit. Ceram. Soc., 66, 293-305.Google Scholar
Malysheva, T.Y. and Batyrev, V.A. (1970) Russ. Met. (Metally)., 3, 8-11.Google Scholar
Mazanek, E. and Jasienska, S. (1968) J. 1ton Steel Inst., 206, 1104-9.Google Scholar
McBriar, E.M., Johnson, W., and Davies, W. (1954) Ibid. 177, 316-23.Google Scholar
Midgely, C.M. (1952) Acta Crystallogr., 5, 307-12.CrossRefGoogle Scholar
Mulvaney, R. (1984) The chemistry and mineralogy of iron ore sinters. Unpubl. PhD thesis, University of Sheffield.Google Scholar
Nyquist, O. (1962) Jernkont. Annlr,, 146, 81-145.Google Scholar
Phillips, B. and Muan, A. (1958) J. Am. Ceram. Soc., 41, 445-54.CrossRefGoogle Scholar
Rankin, G.A. and Wright, F.E. (1915) Am. J. Sei. 39, 1–79 Google Scholar
Scott, P.W., Critchley, S.R., and Wilkinson, F.C. F. (1986) Mineral. Mag., 50, 141-7.CrossRefGoogle Scholar
Tilley, C.E. and Vincent, H.C. G. (1948) Ibid. 28, 255-71.Google Scholar
Wyderko, M. and Mazanek, E. (1968) Ibid. 36, 955-61.Google Scholar
Zerfoss, S. and Davis, H.M. (1943) J. Am. Ceram. Soc., 26, 302-7.Google Scholar