University of Oulu

Wan, X., Shi, C., Huang, Y. et al. Effect of SiO2 and BaO/CaO Mass Ratio on Structure and Viscosity of B2O3-Containing CaF2–CaO–Al2O3-Based Slag for Electroslag Remelting of Rotor Steel. Metall Mater Trans B 54, 465–479 (2023). https://doi.org/10.1007/s11663-022-02706-z

Effect of SiO₂ and BaO/CaO mass ratio on structure and viscosity of B₂O₃-containing CaF₂–CaO–Al₂O₃-based slag for electroslag remelting of rotor steel

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Author: Wan, Xiuxiu1; Shi, Chengbin1; Huang, Yi1;
Organizations: 1State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing (USTB), Beijing, 100083, P.R. China
2Process Metallurgy Research Unit, University of Oulu, 90014, Oulu, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe2023031531910
Language: English
Published: Springer Nature, 2023
Publish Date: 2023-12-19
Description:

Abstract

The structure of 20 mass pct CaF₂–CaO–Al₂O₃-based glasses with different SiO₂ contents and BaO/CaO mass ratios were studied by Raman spectroscopy and MAS-NMR spectroscopy. Aluminum exists exclusively as AlIV species (mainly AlO₄ and secondly AlO₃F). The relative fractions of \({\text{Q}}_{\text{Si}}^{1}\), \({\text{Q}}_{\text{Si}}^{2}\text{(1Al)}\), \({\text{Q}}_{\text{Si}}^{2}\) and \({\text{Q}}_{\text{Si}}^{3}\) structural units significantly increase at the expense of \({\text{Q}}_{\text{Si}}^{0}\) species with increasing SiO₂ content or BaO/CaO mass ratio, leading to enhanced polymerization of aluminosilicate networks. Boron is present in three-coordinated boron species (BIII), except for 1 to 2 pct of four-coordinated boron (BIV) in the glasses with 9.82 and 14.56 mass pct SiO₂ or 8.62 mass pct BaO. BIII is mainly orthoborate containing zero bridging oxygen, and the others are pyroborate with one bridging oxygen. The relative fraction of orthoborate decreases and the relative fraction of pyroborate increases with increasing the SiO₂ content or BaO/CaO mass ratio, bringing an increase in the polymerization of borates. The degree of polymerization of both aluminosilicate networks and borate networks increases with increasing the SiO₂ content or BaO/CaO mass ratio. The viscosity of the slag increases with increasing the SiO₂ content due to increased polymerization degree of the slag melts and bond strength of individual structural unit. The increase in the viscosity with increasing the BaO/CaO mass ratio is dominated by enhanced polymerization degree of the slag.

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Series: Metallurgical and materials transactions. B, Process metallurgy and materials processing science
ISSN: 1073-5615
ISSN-E: 1543-1916
ISSN-L: 1073-5615
Volume: 54
Issue: 1
Pages: 465 - 479
DOI: 10.1007/s11663-022-02706-z
OADOI: https://oadoi.org/10.1007/s11663-022-02706-z
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Funding: The authors are grateful for support from the National Natural Science Foundation of China (Grant Nos. 52074027, 51874026 and 52274314).
Copyright information: © The Minerals, Metals & Materials Society and ASM International 2022. This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s11663-022-02706-z