Experimental study and modelling of viscosity of chromium containing slags
No Thumbnail Available
Journal Title
Journal ISSN
Volume Title
Doctoral thesis (article-based)
Checking the digitized thesis and permission for publishing
Instructions for the author
Instructions for the author
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Author
Date
2007-12-07
Major/Subject
Mcode
Degree programme
Language
en
Pages
64, [54]
Series
Helsinki University of Technology publications in materials science and engineering, 196
Abstract
An apparatus was constructed to measure the viscosities of molten slags at high temperatures up to 1750 °C. Techniques and methods of viscosity measurement for chromium containing slags were developed using a concentric rotating cylinder method in combination with a high temperature furnace. The viscosities were measured for Al2O3-CaO-MgO-SiO2 slags, and for several slag systems containing chromium oxides, from a quasi-binary system CrOx-SiO2 to quasi-ternary and quaternary systems. At low oxygen partial pressures such as in typical metallurgical processes, the chromium in the slag appears simultaneously as divalent (CrO) and trivalent (CrO1.5) oxides. It was proven that decreasing the oxygen partial pressure in the system by contacting the slag with metallic chromium increased the amount of divalent CrO, which consequently lowered the melting temperature and viscosity of the slag as well. The measured data were used to develop viscosity models based on the Iida model, the modified Iida model, the modified Urbain model and neural network algorithm methods. The Iida model and the modified Iida model performed well for slags with relatively low chromium content, less than 5 wt. %. In favour of the Iida model, it must be remembered that the chromium content in metallurgical slags is normally quite low. Also, the modified Urbain model accurately predicted the viscosities of slags with higher chromium levels. The neural network computation also proved to be a promising approach for predicting viscosities of metallurgical slags.Description
Keywords
slag viscosity, viscosity modelling, ferrochromium slag, chromium containing slag
Other note
Parts
- Forsbacka L., Holappa L., Iida T., Kita Y., Toda Y., Experimental study of viscosities of selected CaO-MgO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> slags and application of the Iida model, Scandinavian Journal of Metallurgy, Blackwell Publishing, 2003; 32: 273-280.
- Forsbacka L., Holappa L., Viscosity of CaO-CrO<sub>x</sub>-SiO<sub>2</sub> slags in a relatively high oxygen partial pressure atmosphere, Scandinavian Journal of Metallurgy, 2004; 33: 261-268.
- Forsbacka L., Holappa L., Viscosity of SiO<sub>2</sub>-CaO-CrO<sub>x</sub> slags in contact with metallic chromium and application of the Iida model, Proceedings of the VII International Conference on Molten Slags, Fluxes and Salts, Capetown, South Africa, SAIMM, Johannesburg, 2004, 129-136.
- Forsbacka L., Holappa L., Kondratiev A., Jak E., Experimental study and modelling of viscosity of chromium containing slags, Steel Research International, 2007; 78, no. 9: 676-684.
- Nakamoto M., Forsbacka L., Holappa L., Assessment of viscosity of slags in ferrochromium process, Proceedings of the XI International Conference on Innovations in the Ferro Alloy Industry (INFACON XI), 2007; vol. 1: 159-164.
