Effect of Al2O3 content on the viscosity and structure of CaO-SiO2-Cr2O3-Al2O3 slags

• Published in: International journal of minerals, metallurgy and materials Vol. 29; no. 8; pp. 1522 - 1531
• Main Authors: Yuan, Fang, Zhao, Zheng, Zhang, Yanling, Wu, Tuo
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01-08-2022; Springer Nature B.V; State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China
• Subjects: Aluminum oxide; Calcium oxide; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium oxides; Composites; Corrosion and Coatings; Dissolved organic phosphorus; Glass; High temperature; Materials Science; Metallic Materials; Natural Materials; Raman spectra; Silicon dioxide; Slag; Steel making; Surfaces and Interfaces; Tetrahedra; Thin Films; Tribology; Viscosity; Raman spectra; Cr-containing slag; viscosity; structure
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-021-2306-2

The effect of Al
2
O
3
content on the viscosity and structure of CaO-SiO
2
-Cr
2
O
3
-Al
2
O
3
slags was investigated to facilitate recycling of Cr in steelmaking slags. The slags exhibit good Newtonian behavior at high temperature. The viscosity of acidic slag first increases from 0.825 to 1.141 Pa·s as the Al
2
O
3
content increases from 0 to 10wt% and then decreases to 1.071 Pa·s as the Al
2
O
3
content increases further to 15wt%. The viscosity of basic slag first increases from 0.084 to 0.158 Pa·s as the Al
2
O
3
content increases from 0 to 15wt% and then decreases to 0.135 Pa·s as the Al
2
O
3
content increases further to 20wt%. Furthermore, Cr
2
O
3
-containing slag requires less Al
2
O
3
to reach the maximum viscosity than Cr
2
O
3
-free slag; the Al
2
O
3
contents at which the behavior changes are 10wt% and 15wt% for acidic and basic slags, respectively. The activation energy of the slags is consistent with the viscosity results. Raman spectra demonstrate that [AlO
4
] tetrahedra appear initially and were replaced by [AlO
6
] octahedra with further addition of Al
2
O
3
. The dissolved organic phosphorus content of the slag first increases and then decreases with increasing Al
2
O
3
content, which is consistent with the viscosity and Raman results.