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Thermal expansion of troilite and pyrrhotite determined by in situ cooling (873 to 373 K) neutron powder diffraction measurements

Published online by Cambridge University Press:  05 July 2018

C. Tenailleau ,
B. Etschmann ,
H. Wang ,
A. Pring ,
B. A. Grguric  and
A. Studer
C. Tenailleau
Affiliation:
Mineralogy Department, South Australian Museum, North Terrace, Adelaide, S.A. 5000, Australia
B. Etschmann
Affiliation:
Mineralogy Department, South Australian Museum, North Terrace, Adelaide, S.A. 5000, Australia
H. Wang
Affiliation:
Mineralogy Department, South Australian Museum, North Terrace, Adelaide, S.A. 5000, Australia
A. Pring*
Affiliation:
Mineralogy Department, South Australian Museum, North Terrace, Adelaide, S.A. 5000, Australia Department of Geology and Geophysics, University of Adelaide, North Terrace, Adelaide, S.A. 5005, Australia
B. A. Grguric
Affiliation:
Exploration Group, WMC Resources Ltd, P.O. Box 91, Belmont, W.A. 6984, Australia
A. Studer
Affiliation:
Physics Division, ANSTO, PMB 1 Menai, N.S.W. 2234, Australia
*
E-mail: [email protected]
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Abstract

The thermal expansion coefficients for natural troilite, FeS, Ni-rich pyrrhotite, Fe0.84Ni0.11S, and Ni-poor pyrrhotite, Fe0.87Ni0.02S, were measured during cooling by in situ neutron powder diffraction over the temperature range 873–373 K. Between 873 and 573 K, the mean thermal expansion coefficients for the three compositions are 7.4(3)×10−5 {FeS}, 8.0(4)×10−5 {Fe0.84Ni0.11S} and 8.5(4)×10−5 K−1 {Fe0.87Ni0.02S}. Below 573 down to 373 K, the first two increase considerably to 14.1(7)×10−5 {FeS} and 9.3(5)×10−5 {Fe0.84Ni0.11S} while the latter sample shows no significant variation, 8.4(5)×10−5 K−1. Below 573 K, the thermal expansion is highly anisotropic, with Δa/100 K−1 ranging from 0.89(9)% {FeS} to 0.48(12)% {Fe0.87Ni0.02S} while Δc/100 K−1 ranges from −0.39(11)% {FeS} to −0.13(2)% {Fe0.87Ni0.02S}.

Upon cooling through 573 K, troilite and pyrrhotite undergo a transition where the FeS6 octahedra distort and in the case of pyrrhotite, cation-vacancy clustering occurs. The thermal expansion coefficients are bigger for low cation-vacancy concentrations and decrease as the pyrrhotites become less stoichiometric. This indicates that the thermal expansion in these minerals is damped by vacancy ordering or clustering. The thermal expansion coefficients for troilite and pyrrhotite are amongst the largest reported for sulphide minerals and their role in the formation of ore textures is discussed briefly.

Keywords

thermal expansiontroilitepyrrhotiteα and β transitionsneutron powder diffraction
Type
Research Article
Information
Mineralogical Magazine , Volume 69 , Issue 2 , April 2005 , pp. 205 - 216
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2005

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References

Dutta, B.N. (1962) Lattice constants and thermal expansion of silicon up to 900C. Physical Status Solidi, 2, 984–987.CrossRefGoogle Scholar
Etschmann, B.E, Pring, A., Putnis, A., Grguric, B.A. and Struder, A. (2004) A kinetic study of the exsolution of pentlandite (Ni,Fe)9S8 from the monosulphide solid solution (Fe,Ni)S. American Mineralogist, 89, 39–50.CrossRefGoogle Scholar
Fei, Y. (1995) Thermal Expansion (extract from: Mineral Physics and Crystallography; A handbook of Physical Constants, Ahrens, TJ., editor). American Geophysical Union Reference Shelf, 2, pp. 29–44.Google Scholar
Fleet, M.E. (1971) The crystal structure of a pyrrhotite (Fe7S8). Acta Crystallographica, B27, 1864–1867.CrossRefGoogle Scholar
Hägg, G. and Sucksdorff, I. (1933) Die kristallstruktur von troilit und magnetkies. Zeitschrift fur Physikal Chemie, B22, 444–452.Google Scholar
Haraldsen, H. (1941) Uber die eisen(II)-sulfidmischkristalle. Zeitschrift für Angoranische Chemie, 246, 195–226.Google Scholar
Hunter, B.A. (1997) IUCr Powder Diffraction 22, 21. Rietica 1.7.7. Rietveld Analysis Program.Google Scholar
Ibberson, R.M., David, W.I.F. and Knight, K.S. (1992) The High Resolution Neutron Powder Diffractometer (HRPD) at ISIS - A User Guide. Report RAL-92-031.Google Scholar
Keller-Besrest, F. and Collin, G. (1990a) Structural aspects of the α-transition in stoichiometric FeS: Identification of the high-temperature phase. Journal of Solid State Chemistry, 84, 194–210.CrossRefGoogle Scholar
Keller-Besrest, F. and Collin, G. (1990b) Structural aspects of the α-transition in off-stoichiometric Fe1-xS crystals. Journal of Solid State Chemistry, 84,211–225.CrossRefGoogle Scholar
Kelly, D.P. and Vaughan, D.J. (1983) Pyrrhotine-pentlandite ore textures: a mechanistic approach. Mineralogical Magazine, 47, 453–463.CrossRefGoogle Scholar
King, H.E. and Prewitt, C.T. (1982) High-pressure and high-temperature polymorphism of iron sulphide (FeS). Acta Crystallographica, B38, 1877–1887.CrossRefGoogle Scholar
Misra, K.C. and Fleet, M.E. (1973) Unit cell parameters of monosulphide, pentlandite and taenite solid solutions within the Fe-Ni-S system. Materials Research Bulletin, 8, 669–678.CrossRefGoogle Scholar
Morimoto, N., Gyobu, A., Tsukuma, K. and Koto, K. (1975a) Superstructure and nonstoichiometry of intermediate pyrrhotite. American Mineralogist, 60, 240–248.Google Scholar
Morimoto, N., Gyobu, A., Mukaiyama, H. and Izawa, E. (1975b) Crystallography and stability of pyrrhotites. Economic Geology, 70, 824–833.CrossRefGoogle Scholar
Nakazama, H. and Morimoto, N. (1971) Phase relations and superstructures of pyrrhotite, Fe1-xS. Materials Research Bulletin, 6, 345–358.CrossRefGoogle Scholar
Pósfai, M. and Dódony, I. (1990) Pyrrhotite super-structures. Part I: Fundamental structures of the NC (N=2, 3, 4 and 5) type. European Journal of Mineralogy, 2, 525–528.CrossRefGoogle Scholar
Powell, A.V., Vaqueiro, P., Knight, K.S., Chapon, L.C. and Sanchez, R.D. (2004) Structure and magnetism in synthetic pyrrhotite Fe7S8: A powder neutron-diffraction study. Physical Review B (Condensed Matter and Materials Physics - 1), 70, 014415.CrossRefGoogle Scholar
Rajamani, V. and Prewitt, C.T. (1975) Thermal expansion of the pentlandite structure. American Mineralogist, 60, 39–48.Google Scholar
Roberts, D.E. and Travis, G.A. (1986) Microtextural evaluation of nickel sulphide gossans in Western Australia. Transaction of the Royal Society of Edinburgh: Earth Sciences, 77, 81–98.CrossRefGoogle Scholar
Schwarz, E.J. and Vaughan, D.J. (1972) Magnetic phase relations of pyrrhotite. Journal of Geomagnetism and Geoelectricity, 24, 441–458.CrossRefGoogle Scholar
Sugaki, A. and Kitakaze, A. (1998) High form of pentlandite and its thermal stability. American Mineralogist, 83, 133–140.CrossRefGoogle Scholar
Taylor, L.A. (1970) Low temperature phase relations in the Fe-S system. Carnegie Institute of Washington Year Book, 68, 259–267.Google Scholar
Thomas, J.E., Skinner, W.M. and Smart, R.St.C. (2001) A mechanism to explain sudden changes in rates and products for pyrrhotite dissolution in acid solution Geochimica et Cosmochimica Acta, 65, 1–12.CrossRefGoogle Scholar
Thomas, J.E., Skinner, W.M. and Smart R.St.C. (2003) A comparison of the dissolution behavior of troilite with other iron(II) sulfides; implications of structure. Geochimica et Cosmochimica Acta, 61, 831–843.CrossRefGoogle Scholar
Tokonami, M., Nishiguchi, K. and Monmoto, N. (1972) Crystal structure of a monoclinic pyrrhotite (Fe7S8). American Mineralogist, 37, 1066–1080.Google Scholar
Tsatis, D.E. (1988) Thermal expansion of pyrrhotite (Fe7S8) at high temperatures. Journal of Physics and Chemistry of Solids, 49, 359–362.CrossRefGoogle Scholar
Vaughan, D.J. and Craig, J.R. (1978) Mineral Chemistry of Metal Sulphides. Cambridge University Press, Cambridge, UK, 493 pp.Google Scholar
Wang, H., Pring, A., Ngothai, Y. and O'Neill, B. (2005) A low temperature kinetic study of the exsolution of pentlandite from the monosulfide solid solution using a refined Ayrami equation. Geochimica et Cosmochimica Acta, 69, 415–425.CrossRefGoogle Scholar