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
Dissolution of Lime in Synthetic 'FeO'-SiO2 and CaO-'FeO'-SiO2 Slags
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Micro-Modelling.ORCID iD: 0000-0002-3548-8638
2010 (English)In: Steel Research International, ISSN 1611-3683, Vol. 81, no 5, 347-355 p.Article in journal (Refereed) Published
Abstract [en]

Dissolution of different CaO samples into molten synthetic 'FeO'-SiO2 and 'FeO'-SiO2-CaO slags was carried out in a closed tube furnace at 1873K. The slag was kept stagnant. It was found that the dissolution rate was very fast when CaO rod was dipped into 'FeO'-SiO2 slag. In the case of 'FeO'-SiO2-CaO slag, the dissolution of CaO rod in the stagnant slag was retarded after the initial period (2 minutes). Only less than 16 percent CaO reacted with the slag, irrespective of the type of lime. Three phase-regions were identified in the reacted part of the lime rod by SEM-EDS analysis. The formation of these regions was explained thermodynamically. A dense layer of 2CaO center dot SiO2 was found to be responsible for the total stop of the dissolution. It could be concluded that constant removal of the 2CaO center dot SiO2 layer would be of essence to obtain a high dissolution rate of lime. In this connection, it was found necessary to study the dissolution of lime in moving slag to reach a reliable conclusion regarding the relevance of the reactivity obtained by water ATSM test to the real reactivity of lime in high temperature slag.

Place, publisher, year, edition, pages
2010. Vol. 81, no 5, 347-355 p.
Keyword [en]
Lime, Slag, Dissolution
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-27521DOI: 10.1002/srin.201000017ISI: 000278292200003Scopus ID: 2-s2.0-77953955982OAI: oai:DiVA.org:kth-27521DiVA: diva2:379495
Note
QC 20101217Available from: 2010-12-17 Created: 2010-12-13 Last updated: 2012-08-29Bibliographically approved
In thesis
1. Study on the dissolution of lime and dolomite in converter slag
Open this publication in new window or tab >>Study on the dissolution of lime and dolomite in converter slag
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In the present study, the dissolution mechanism and rate of lime, limestone and dolomite in converter slag was studied. Lime dissolution in stagnant slag was studied first and dissolution of lime, limestone and dolomite under forced convection were carried out by new experimental setup.

Dissolution of different CaO samples into stagnant converter slags was carried out in a closed tube furnace at 1873K. In the case of CaO-‘FeO’-SiO2 slag, the dissolution of CaO rod in the stagnant slag was retarded after the initial period (2 minutes). A dense layer of 2CaO∙SiO2 was found to be responsible for the total stop of the dissolution. It could be concluded that constant removal of the 2CaO∙SiO2 layer would be of essence to obtain high dissolution rate of lime. In this connection, it was found necessary to study the dissolution of lime in moving slag.

In order to obtain reliable information of lime dissolution under forced convection, the commonly used rotating rod method was examined. Both CFD calculation and cold model experiments showed evidently that the mass transfer due to radial velocity introduced by forced convection was zero if the rod was centrally placed in a cylindrical container. A new experimental design was therefore developed. A cube was placed in the crucible and stirred by Mo rod along with slag. The whole system could be quenched in order to maintain the state of the system at high temperature. A linear relationship between normalized length and time was obtained for lime dissolution. Different lime samples showed big difference in dissolution rate. It was found that the main mechanism of CaO dissolution in slag was due to the removal of 2CaO∙SiO2 layer.

Decomposition and dissolution of limestone and dolomite in slag at 1873 K were studied. The decomposition was carried out both in argon and in slag under argon atmosphere. The decomposition process was simulated using Comsol. The results showed evidently that the decomposition of limestone and dolomite was controlled mostly by heat transfer.

It was also found that the decomposition of limestone product: CaO had very dense structure, no matter the sample was decomposed in slag or in argon. The slow decomposition and the dense CaO layer would greatly hinder the dissolution of lime in the slag. The present results clearly indicate that addition of limestone instead of lime would not be beneficial in converter process.

Discontinuous 2CaO∙SiO2 layer along with MgO∙Fe2O3 particles was found on the surface of the dolomite sample. Some 2CaO∙SiO2 islands were found in the vicinity of the sample in the slag, which revealed therefore that the dissolution was dominated by the peeling-off of the layer of 2CaO∙SiO2-MgO∙Fe2O3 mixture. 2CaO∙SiO2, (Mg, Fe)Oss along with super cooled liquid phases were found inside dolomite sample close to the surface. 2CaO∙SiO2 phase was replaced gradually by 3CaO∙SiO2 towards the centre of the decomposed sample.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. 45 p.
Keyword
dissolution, lime, limestone, dolomite, converter slag
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-101461 (URN)978-91-7501-454-8 (ISBN)
Public defence
2012-09-28, B1, Brinellvägen 23, Kungliga Tekniska Högskolan, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20120829

Available from: 2012-08-29 Created: 2012-08-29 Last updated: 2013-03-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Sichen, Du

Search in DiVA

By author/editor
Deng, TengfeiGran, JimmySichen, Du
By organisation
Micro-Modelling
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 266 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