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A revised phase diagram for the bornite-digenite join from in situ neutron diffraction and DSC experiments

Published online by Cambridge University Press:  05 July 2018

B. A. Grguric ,
R. J. Harrison  and
A. Putnis
B. A. Grguric
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
R. J. Harrison
Affiliation:
Institut für Mineralogie, Universität Münster, Corrensstrasse 24, D-48149 Münster, Germany
A. Putnis*
Affiliation:
Institut für Mineralogie, Universität Münster, Corrensstrasse 24, D-48149 Münster, Germany
*
*E-mail: [email protected]
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Abstract

Phase relations along the join bornite (Cu5FeS4)-digenite (Cu8.52Fe0.12S4.88) have been redefined using a combination of in situ high-resolution neutron diffraction and differential scanning calorimetry (DSC). Time-of-flight neutron diffraction patterns were collected on a synthetic sample of bn90 at 16 temperatures between 35 and 350°C. This data is compared with data from a natural end-member bornite sample obtained in an earlier study under identical conditions. Phase relations along the bornite-digenite join are inferred from the temperature evolution of the lattice parameters and the intensity of subcell and supercell reflections of coexisting phases.

The DSC scans over the temperature range 50–300°C were performed on a natural digenite sample and samples synthesized at 5 mol.% intervals along the join Cu5FeS4-Cu9S5. The thermal anomalies are correlated with structural phase transitions in componen phases and the solvus temperature for each bulk composition. A phase diagram topology is defined, which was consistent with both diffraction and calorimetric data, but in marked contrast to previous diagrams, shows a consolute point at X = Cu5FeS4 and T = 265°C. This temperature corresponds to that of the tricritical intermediate-high transition in bornite. Isothermal annealing experiments carried out on synthetic starting materials for up to 7 months showed coarsening behaviour consistent with the revised phase diagram topology.

Keywords

bornitedigenitedifferential scanning calorimetryneutron diffractionexsolution
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 2 , April 2000 , pp. 213 - 231
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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Footnotes

†

Present address: Department of Geology and Resource Evaluation, WMC Mount Keith Operations, P.O. Box 238, Welshpool Delivery Centre, W.A. 6986, Australia

References

Berger, R. and Bucur, R.V. (1996) Potentiometric measurements of copper diffusion in polycrystalline chalcocite, chalcopyrite and bornite. Solid State Ionics, 89, 269–78.CrossRefGoogle Scholar
Brett, P.R. (1963) The Cu-Fe-S system. Carnegie Institute of Washington Yearbook, 62, 193–6.Google Scholar
Brett, R. (1964) Experimental data from the system Cu-Fe-S and their bearing on exsolution textures in ores. Econ. Geol., 59, 1241–69.CrossRefGoogle Scholar
Callanan, J.E. and Sullivan, S.A. (1986) Development of standard operating procedures for differential scanning calorimeters. Rev. Sci. Instr., 57, 2584–92.CrossRefGoogle Scholar
David, W.I.F., Akporiaye, R.M., Ibberson, R.M. and Wilson, C.C. (1988) The high resolution powder diffractometer at ISIS: an introductory user guide. Rutherford Appleton Laboratory Report.Google Scholar
Gordon, P. (1968) Principles of Phase Diagrams in Materials Systems. McGraw-Hill.Google Scholar
Grguric, B.A. and Putnis, A. (1998) Compositional controls on phase transition temperatures in bornite: a differential scanning calorimetry study. Canad. Mineral., 36, 215–27.Google Scholar
Grguric, B.A. and Putnis, A. (1999) Rapid exsolution behaviour in the bornite-digenite series: implications for natural ore assemblages. Mineral. Mag., 63, 1–14.CrossRefGoogle Scholar
Grguric, B.A., Putnis, A. and Harrison, R.J. (1998) An investigation of the phase transitions in bornite (Cu5FeS4) using neutron diffraction and differential scanning calorimetry. Amer. Mineral., 83, 1231–9.CrossRefGoogle Scholar
Grùnvold, F. and Westrum, E.F. (1980) The anilite/lowdigenite transition. Amer. Mineral., 65, 574–5.Google Scholar
Holland, T.J.B. and Redfern, S.A.T. (1997) Unit cell refinement from powder diffraction data: the use of regression diagnostics. Mineral. Mag., 61, 65–77.CrossRefGoogle Scholar
Ibberson, R.M., David, W.I.F. and Knight, K.S. (1992) The high resolution powder diffractometer (HRPD) at ISIS – a user guide. Rutherford Appleton Laboratory Report RAL-92-031.Google Scholar
Kanazawa, Y., Koto, K. and Morimoto, N. (1978) Bornite (Cu5FeS4): stability and crystal structure of the intermedi ate form. Canad. Mineral., 16, 397–404.Google Scholar
Koto, K. and Morimoto, N. (1975) Superstructure investigation of bornite, Cu5FeS4, by the modified partial Patterson function. Acta Crystallogr., B31, 2268–73.CrossRefGoogle Scholar
Kullerud, G. (1960) The Cu9S5-Cu5FeS4 join. Carnegie Institute of Washington Yearbook, 59, 114–6.Google Scholar
Morimoto, N. (1970) Crystal-chemical studies on the Cu-Fe-S system. In: Volcanism and Ore Genesis (Tatsumi, T., editor). University of Tokyo Press.Google Scholar
Morimoto, N. and Gyobu, A. (1971) The composition and stability of digenite. Amer. Mineral., 56, 1889–909.Google Scholar
Morimoto, N. and Koto, K. (1970) Phase relations of the Cu-S system at low temperatures: stability of anilite. Amer. Mineral., 55, 106–17.Google Scholar
Morimoto, N. and Kullerud, G. (1963) Polymorphism in digenite. Amer. Mineral., 48, 110–123.Google Scholar
Morimoto, N. and Kullerud, G. (1966) Polymorphism on the Cu9S5-Cu5FeS4 join. Zeits. Kristallogr., 123, 235–54.CrossRefGoogle Scholar
Pierce, L. and Buseck, P.R. (1978) Superstructuring in the bornite-digenite series: a high resolution electron microscope study. Amer. Mineral., 63, 1–16.Google Scholar
Porter, D.A. and Easterling, K.E. (1992) Phase Transitions in Metals and Alloys. 2nd edition, Chapman & Hall, London.CrossRefGoogle Scholar
Pósfai, M. and Buseck, P.R. (1994) Djurleite, digenite, and chalcocite: intergrowths and transformations. Amer. Mineral., 79, 308–15.Google Scholar
Putnis, A. and Grace, J. (1976) The transformation behaviour of bornite. Contrib. Mineral. Petrol., 55, 311–55.CrossRefGoogle Scholar
Roseboom, E.H. (1966) An investigation of the system Cu-S and some natural copper sul. des between 258 and 700°C. Econ. Geol., 61, 641–72CrossRefGoogle Scholar
Smallman, R.E. (1985) Modern Physical Metallurgy, 4th edition. Butterworths.Google Scholar
Yund, R.A. and McCallister, R.H. (1970) Kinetics and mechanisms of exsolution. Chem. Geol., 6, 5–30.CrossRefGoogle Scholar