FT-IR Spectroscopic Study on Structure of CaO-SiO2 and CaO-SiO2-CaF2 Slags.

• Park Joo Hyun

  Department of Metallurgical Engineering, Yonsei University

• Min Dong Joon

  Department of Metallurgical Engineering, Yonsei University

• Song Hyo Seok

  Stainless Steel Research Group, Technical Research Laboratory, POSCO

Abstract

The FT-IR spectra of the CaO-SiO₂ and CaO-SiO₂-CaF₂ slags were measured to understand the structural aspects of (fluoro-) silicate systems. The relative intensity of Si-O rocking band is very strong at SiO₂ saturation condition and this band disappears in the composition greater than 44.1 (mol%) CaO in the CaO-SiO₂ binary system. The bands for [SiO₄]-tetrahedra at about 1 150-760 cm^-1 split up with increasing content of CaO greater than 44.1 mol%. The IR bands in this wavenumber range are divided into four groups, that is about 1090, 990, 920, and 870 cm^-1, which have been assigned to NBO/Si=1, 2, 3, and 4, respectively. In the CaO-SiO₂ -CaF₂ (2CaO · SiO₂-Satd.) system, the center of gravity of the bands at about 1170-710 cm^-1 shifts from about 980 to 850 cm^-1 by increasing the ratio X_CaF₂/X_SiO₂ from 0.22 to 0.64. The bands for [SiO₄]-tetrahedra are observed from about 1 070 to 730 cm^-1 in the CaO-17.6(mol%)SiO₂-CaF₂ system, while these bands are observed from about 1120 to 720 cm^-1 in the CaO-40.0(mol%)SiO₂-CaF₂ system. The effect of substitution of CaF₂ for CaO on the depolymerization of silicate network is observed to significantly depend on the SiO₂ content in the slags. The bands for [SiO₄]-tetrahedra are observed from about 1110 to 720 cm^-1 in the CaO-SiO₂ -14.1(mol%)CaF₂ system and the center of gravity of these bands shifts from about 990 to 850 cm^-1 with increasing CaO/SiO₂ ratio. The fraction of the relatively depolymerized units continuously increases from about 0.5 to 0.8 as the composition of slags changes from 2CaO · SiO₂ to CaO saturation condition.

Journal

• ISIJ International

  ISIJ International 42 (4), 344-351, 2002

  The Iron and Steel Institute of Japan

Keywords

• FT-IR spectra
• Si-O rocking
• [SiO₄]-tetrahedra
• NBO/Si
• depolymerization
• silicate network

Details

• CRID: 1390001206451115392
• NII Article ID: 10008008787
• NII Book ID: AA10680712
• DOI: 10.2355/isijinternational.42.344
• COI: 1:CAS:528:DC%2BD38XksVyrsLc%3D
• ISSN: 13475460
• ISSN: 09151559
• ISSN: http://id.crossref.org/issn/00211583
• ISSN: http://id.crossref.org/issn/09151559
• Web Site: http://www.jstage.jst.go.jp/article/isijinternational1989/42/4/42_4_344/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed