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Pyrite: Linking Mossbauer spectroscopy to mineral magnetism

Ferrow, Embaie LU ; Sjoberg, BA and Mannerstrand, Maria LU (2003) Conference of the NATO Advanced Research Workshop on Material Research in Atomic Scale by Mossbauer Spectroscopy In Material Research in Atomic Scale by Mössbauer Spectroscopy 94. p.251-259
Abstract
Gold-bearing pyrite ores are refractory and must be pre-treated to break down the sulphides by oxidation. This is done usually by roasting, bacterial oxidation and smelting. Moreover, ores with high sulphur content require pre-treatment to prevent excessive chlorine consumption, an important source of pollution. The pyrite waste created in mining operation presents serious problems on the environmental impact of acid mine drainage. In order to improve separation of pyrite from other metals as well as for the development of new strategies to inhibit oxidation of pyrite, it is necessary to understand the thermal, chemical, magnetic and biological implications during alteration of pyrite. The oxidation of pyrite in air was studied using... (More)
Gold-bearing pyrite ores are refractory and must be pre-treated to break down the sulphides by oxidation. This is done usually by roasting, bacterial oxidation and smelting. Moreover, ores with high sulphur content require pre-treatment to prevent excessive chlorine consumption, an important source of pollution. The pyrite waste created in mining operation presents serious problems on the environmental impact of acid mine drainage. In order to improve separation of pyrite from other metals as well as for the development of new strategies to inhibit oxidation of pyrite, it is necessary to understand the thermal, chemical, magnetic and biological implications during alteration of pyrite. The oxidation of pyrite in air was studied using Mossbauer spectroscopy and mineral magnetic methods. A pyrite concretion from biogenic limestone shows a very weak natural remanent magnetization. Heating of the pyrite produced alpha-hematite as the end product. Intermediate mineral phases created during heating depend mainly on temperature, heating rate, grain size and the atmosphere in the oven. The most magnetic phases occur about 500 T as determined from magnetic susceptibility and hysteresis measurements. The components of the compound hysteresis were iron sulphates and polymorphs of hematite as determined by Mossbauer spectroscopy. Heating of powder of pyrite produced higher concentration of pyrrhotite than grains of mm size as a result of more thorough oxidation as a result of increased ratio of iron to sulphur produced by degassing during heating. Since pyrite and its oxidation products are all Fe-bearing phases, combining Mossbauer spectroscopy with rock magnetic methods provides information to monitor the oxidation of pyrite in air and identify the different phases produced and their relation to different experimental parameters. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
Material Research in Atomic Scale by Mössbauer Spectroscopy
volume
94
pages
251 - 259
publisher
Springer
conference name
Conference of the NATO Advanced Research Workshop on Material Research in Atomic Scale by Mossbauer Spectroscopy
external identifiers
  • WOS:000183172700026
ISBN
1-4020-1196-2
language
English
LU publication?
yes
id
046c1753-51c8-4b41-98e9-bf6daf67b7d8 (old id 1406965)
date added to LUP
2009-06-03 13:58:34
date last changed
2016-04-16 10:33:11
@misc{046c1753-51c8-4b41-98e9-bf6daf67b7d8,
  abstract     = {Gold-bearing pyrite ores are refractory and must be pre-treated to break down the sulphides by oxidation. This is done usually by roasting, bacterial oxidation and smelting. Moreover, ores with high sulphur content require pre-treatment to prevent excessive chlorine consumption, an important source of pollution. The pyrite waste created in mining operation presents serious problems on the environmental impact of acid mine drainage. In order to improve separation of pyrite from other metals as well as for the development of new strategies to inhibit oxidation of pyrite, it is necessary to understand the thermal, chemical, magnetic and biological implications during alteration of pyrite. The oxidation of pyrite in air was studied using Mossbauer spectroscopy and mineral magnetic methods. A pyrite concretion from biogenic limestone shows a very weak natural remanent magnetization. Heating of the pyrite produced alpha-hematite as the end product. Intermediate mineral phases created during heating depend mainly on temperature, heating rate, grain size and the atmosphere in the oven. The most magnetic phases occur about 500 T as determined from magnetic susceptibility and hysteresis measurements. The components of the compound hysteresis were iron sulphates and polymorphs of hematite as determined by Mossbauer spectroscopy. Heating of powder of pyrite produced higher concentration of pyrrhotite than grains of mm size as a result of more thorough oxidation as a result of increased ratio of iron to sulphur produced by degassing during heating. Since pyrite and its oxidation products are all Fe-bearing phases, combining Mossbauer spectroscopy with rock magnetic methods provides information to monitor the oxidation of pyrite in air and identify the different phases produced and their relation to different experimental parameters.},
  author       = {Ferrow, Embaie and Sjoberg, BA and Mannerstrand, Maria},
  isbn         = {1-4020-1196-2},
  language     = {eng},
  pages        = {251--259},
  publisher    = {ARRAY(0xbdadad0)},
  series       = {Material Research in Atomic Scale by Mössbauer Spectroscopy},
  title        = {Pyrite: Linking Mossbauer spectroscopy to mineral magnetism},
  volume       = {94},
  year         = {2003},
}