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Characterization of pyrrhotite in Cu-Ni-ore bodies from mines in Botswana by Mossbauer spectroscopy, X-ray diffraction, and thermomagnetometry

Ferrow, Embaie LU ; Adetunji, Jacob and Nkoma, John S. (2006) In European Journal of Mineralogy 18(5). p.653-664
Abstract
Cu-Ni ore bodies from five Botswana mines were investigated, using a combination of X-ray diffraction, thermomagnetic measurements, Mossbauer spectroscopy, and Inductively Coupled Plasma-Atomic Absorption Electro-optic Spectroscopy (ICP-AES). The four dominant phases in the ores were found to be pyrrhotite, magnetite, pentlandite, and chalcopyrite. Mossbauer spectroscopy shows that pyrrhotite is the dominant Fe-bearing phase in the samples with 75 % in B-S1, 84 % in B-S2, and 80 % in B-S4 and was selected for detailed characterization. Our results show that the three first techniques provide an excellent approach to estimate the degree of polytype intermixing in pyrrhotite. Accordingly, the ores can be grouped into three types: A hexagonal... (More)
Cu-Ni ore bodies from five Botswana mines were investigated, using a combination of X-ray diffraction, thermomagnetic measurements, Mossbauer spectroscopy, and Inductively Coupled Plasma-Atomic Absorption Electro-optic Spectroscopy (ICP-AES). The four dominant phases in the ores were found to be pyrrhotite, magnetite, pentlandite, and chalcopyrite. Mossbauer spectroscopy shows that pyrrhotite is the dominant Fe-bearing phase in the samples with 75 % in B-S1, 84 % in B-S2, and 80 % in B-S4 and was selected for detailed characterization. Our results show that the three first techniques provide an excellent approach to estimate the degree of polytype intermixing in pyrrhotite. Accordingly, the ores can be grouped into three types: A hexagonal (or peak-type), with a 5c stacking arrangement; a monoclinic (or Weiss-type), with a 4c stacking arrangement; and a mixture of monoclinic and hexagonal types. A low-temperature study of the monoclinic form shows that the low-temperature magnetic transition close to 35 K has features similar to the Verwey transition in magnetite induced by Jahn-Teller distortion due to orbital order-disorder transition. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
magnetism, pyrrhotite, Mossbauer spectroscopy, Verwey transition, polytype
in
European Journal of Mineralogy
volume
18
issue
5
pages
653 - 664
publisher
E Schweizerbartsche Verlags
external identifiers
  • wos:000241928900012
  • scopus:71149111066
ISSN
1617-4011
DOI
10.1127/0935-1221/2006/0018-0653
language
English
LU publication?
yes
id
27f80b38-f87a-47ba-9864-34b9eb31ae15 (old id 377114)
date added to LUP
2007-10-02 19:53:24
date last changed
2019-02-20 04:18:50
@article{27f80b38-f87a-47ba-9864-34b9eb31ae15,
  abstract     = {Cu-Ni ore bodies from five Botswana mines were investigated, using a combination of X-ray diffraction, thermomagnetic measurements, Mossbauer spectroscopy, and Inductively Coupled Plasma-Atomic Absorption Electro-optic Spectroscopy (ICP-AES). The four dominant phases in the ores were found to be pyrrhotite, magnetite, pentlandite, and chalcopyrite. Mossbauer spectroscopy shows that pyrrhotite is the dominant Fe-bearing phase in the samples with 75 % in B-S1, 84 % in B-S2, and 80 % in B-S4 and was selected for detailed characterization. Our results show that the three first techniques provide an excellent approach to estimate the degree of polytype intermixing in pyrrhotite. Accordingly, the ores can be grouped into three types: A hexagonal (or peak-type), with a 5c stacking arrangement; a monoclinic (or Weiss-type), with a 4c stacking arrangement; and a mixture of monoclinic and hexagonal types. A low-temperature study of the monoclinic form shows that the low-temperature magnetic transition close to 35 K has features similar to the Verwey transition in magnetite induced by Jahn-Teller distortion due to orbital order-disorder transition.},
  author       = {Ferrow, Embaie and Adetunji, Jacob and Nkoma, John S.},
  issn         = {1617-4011},
  keyword      = {magnetism,pyrrhotite,Mossbauer spectroscopy,Verwey transition,polytype},
  language     = {eng},
  number       = {5},
  pages        = {653--664},
  publisher    = {E Schweizerbartsche Verlags},
  series       = {European Journal of Mineralogy},
  title        = {Characterization of pyrrhotite in Cu-Ni-ore bodies from mines in Botswana by Mossbauer spectroscopy, X-ray diffraction, and thermomagnetometry},
  url          = {http://dx.doi.org/10.1127/0935-1221/2006/0018-0653},
  volume       = {18},
  year         = {2006},
}