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Crystallite size of haematite from thermal oxidation of pyrite and marcasite - effects of grain size and iron disulphide polymorph

Eneroth, Erik LU and Koch, CB (2003) In Minerals Engineering 16(11, Suppl.1). p.1257-1267
Abstract
A study relating the properties of haematite (alpha-Fe2O3) produced by thermal oxidation of pyrite and marcasite (both FeS2) in air for 1 h at temperatures between 200 and 650 degreesC, to the iron disulphide polymorph and grain size of the sample is reported. Comparisons feature crystallite sizes of haematite from pyrite and marcasite oxidation, and the 125-250 and 710-1000 mum fractions. The crystallite sizes of the haematite were obtained from analysis of the broadening of X-ray diffraction lines. Haematite could be detected at temperatures above 450-475 degreesC for both pyrite and marcasite. The results show that the initial haematite crystallites forming are equidimensional, having dimensions of approximately 15-20 nm following... (More)
A study relating the properties of haematite (alpha-Fe2O3) produced by thermal oxidation of pyrite and marcasite (both FeS2) in air for 1 h at temperatures between 200 and 650 degreesC, to the iron disulphide polymorph and grain size of the sample is reported. Comparisons feature crystallite sizes of haematite from pyrite and marcasite oxidation, and the 125-250 and 710-1000 mum fractions. The crystallite sizes of the haematite were obtained from analysis of the broadening of X-ray diffraction lines. Haematite could be detected at temperatures above 450-475 degreesC for both pyrite and marcasite. The results show that the initial haematite crystallites forming are equidimensional, having dimensions of approximately 15-20 nm following oxidation at around 500 C. At higher temperatures the crystallites develop a platy habit by sintering, and at 650 degreesC mean crystallite dimensions of 25-35 nm along c-axis and 45-60 nm along a-axis were found. Model surface areas calculated from XRD fall within the range 80-20 m(2)/g. Oxidation of the 710-1000 mum size fractions produced significantly larger crystallites than the 125-250 mum fractions. A comparison of the polymorphs shows that haematite crystals from marcasite were smaller than those forming from pyrite. The oxidation followed a reaction route favouring higher oxidation states of iron. (C) 2003 Elsevier Ltd. All rights reserved. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
particle size, pyrometallurgy, sulphide ores, oxidation, environmental
in
Minerals Engineering
volume
16
issue
11, Suppl.1
pages
1257 - 1267
publisher
Pergamon
external identifiers
  • wos:000186870200005
  • scopus:0345328287
ISSN
0892-6875
DOI
language
English
LU publication?
yes
id
204c45aa-a4ce-44b2-83bc-3bed7faea091 (old id 294406)
date added to LUP
2007-08-29 15:16:10
date last changed
2018-05-29 12:14:12
@article{204c45aa-a4ce-44b2-83bc-3bed7faea091,
  abstract     = {A study relating the properties of haematite (alpha-Fe2O3) produced by thermal oxidation of pyrite and marcasite (both FeS2) in air for 1 h at temperatures between 200 and 650 degreesC, to the iron disulphide polymorph and grain size of the sample is reported. Comparisons feature crystallite sizes of haematite from pyrite and marcasite oxidation, and the 125-250 and 710-1000 mum fractions. The crystallite sizes of the haematite were obtained from analysis of the broadening of X-ray diffraction lines. Haematite could be detected at temperatures above 450-475 degreesC for both pyrite and marcasite. The results show that the initial haematite crystallites forming are equidimensional, having dimensions of approximately 15-20 nm following oxidation at around 500 C. At higher temperatures the crystallites develop a platy habit by sintering, and at 650 degreesC mean crystallite dimensions of 25-35 nm along c-axis and 45-60 nm along a-axis were found. Model surface areas calculated from XRD fall within the range 80-20 m(2)/g. Oxidation of the 710-1000 mum size fractions produced significantly larger crystallites than the 125-250 mum fractions. A comparison of the polymorphs shows that haematite crystals from marcasite were smaller than those forming from pyrite. The oxidation followed a reaction route favouring higher oxidation states of iron. (C) 2003 Elsevier Ltd. All rights reserved.},
  author       = {Eneroth, Erik and Koch, CB},
  issn         = {0892-6875},
  keyword      = {particle size,pyrometallurgy,sulphide ores,oxidation,environmental},
  language     = {eng},
  number       = {11, Suppl.1},
  pages        = {1257--1267},
  publisher    = {Pergamon},
  series       = {Minerals Engineering},
  title        = {Crystallite size of haematite from thermal oxidation of pyrite and marcasite - effects of grain size and iron disulphide polymorph},
  url          = {http://dx.doi.org/},
  volume       = {16},
  year         = {2003},
}