Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Effect of oxygen partial pressure on the chromium partition in CaO-MgO-SiO2-Cr2o3 synthetic slag at 1673 k
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
(English)Manuscript (preprint) (Other academic)
Keyword [en]
Cr2O3 containing slags, gas-slag equilibrium, chromium partition, spinel
National Category
Metallurgy and Metallic Materials
Identifiers
URN: urn:nbn:se:kth:diva-50929OAI: oai:DiVA.org:kth-50929DiVA: diva2:463071
Available from: 2011-12-08 Created: 2011-12-08 Last updated: 2011-12-08Bibliographically approved
In thesis
1. Investigations of Stabilization of Cr in Spinel Phase in Chromium-Containing Slags
Open this publication in new window or tab >>Investigations of Stabilization of Cr in Spinel Phase in Chromium-Containing Slags
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The influence of basicity, heat treatment as well as different oxygen partial pressures on the phase relationships in the CaO-MgO-SiO2-Cr2O3 slags was studied with a view to control the precipitation of Cr-spinel in the slag phase. The equilibrium phases in CaO-MgO-SiO2-Cr2O3 slag system in the range on 1673-1873 K have been investigated under low oxygen partial pressure as well as in as air atmosphere. In low oxygen partial pressure experiments, a suitable mixture of CO and CO2 was used to control the oxygen partial pressure. The oxygen partial pressure was kept at 10-4 Pa. The Cr2O3 and MgO contents in the slag were fixed to be 6 and 8wt% respectively. The basicity (CaO/ SiO2) of the slag was varied in the range 1.0-2.0. Gas/slag equilibrium technique was adopted to synthesize the slag at a suitable temperature above the liquidus point. One heat treatment procedure is that the samples were heated to and soaked at 1873 K for 24h in order to achieve the equilibrium state and subsequently quenched in water. The other is that the samples were heated to and soaked at 1873 K for 24h, then slow cooled to 1673 K and soaked at this temperature for additional 24h in order to achieve the equilibrium state at lower temperature before quenching in water. The chromium distribution and phase compositions in the quenched slag were studied using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction techniques (XRD). FACTsage software was used for the phase equilibrium calculations. The experimental results obtained from the present work are compared with the calculation results from FACTsage software as well as with results from samples directly quenched after soaking at 1873K. It is found that the spinel formation at 1873 K in air atmosphere is favored in the slag basicity range of 1.0 to 1.6. The size of spinel crystals increased drastically after slow cooling followed by annealing compared to samples being quenched after soaking at 1873 K. The amount of foreign elements dissolved in the spinel phase, and matrix phases decreased after slow cooling followed by annealing at lower temperature, resulting in purer phases with less defects. It was found that the amount of foreign elements in the spinel phase, and other phases decreased after soaking at very low PO2. The size of the spinel crystals was found to be larger in samples with low basicity. Spinel phase precipitation has improved in the samples with higher basicities compared to the results obtained in air.

 

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. vi, 42 p.
Keyword
Cr2O3 containing slags, gas-slag equilibrium, chromium partition, spinel
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-50709 (URN)978-91-7501-207-0 (ISBN)
Presentation
2011-12-16, Sal B23, KTH, Brinellvägen 23, Stockholm, 10:00
Opponent
Supervisors
Note
QC 20111208Available from: 2011-12-08 Created: 2011-12-07 Last updated: 2011-12-08Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Jelkina Albertsson, Galina
By organisation
Materials Process Science
Metallurgy and Metallic Materials

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 68 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf