Title

PHASE DIAGRAM CALCULATION OF HIGH ALUMINA BLAST FURNACE SLAG SYSTEMS AND EXPERIMENTAL STUDY OF THEIR FLUIDITY

PHASE DIAGRAM CALCULATION OF HIGH ALUMINA BLAST FURNACE SLAG SYSTEMS AND EXPERIMENTAL STUDY OF THEIR FLUIDITY

Authorship

Bi, Xue-gong; Rao, Changrun; Yang., Fu

Bi, Xue-gong

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Rao, Changrun

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Yang., Fu

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DOI

10.5151/2594-357X-22144

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Abstract

Firstly, the commercial thermodynamic software package FactSage was applied in the calculation of phase diagram from the view point of melting point for the definition of slag composition range at different Al2O3 content levels; secondly, the KTH melt viscosity model was used in viscosity at 1,450°C calculation for slag compositions proposed by FactSage; thirdly, slag specimen were prepared with Al2O3 content of 18 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.% for viscosity experiments based on analysis of the above theoretical calculation results; and finally optimization schemes were proposed of blast furnace slag composition at different Al2O3 content levels. This kind of research method with the combination of theory and experiment accelerated remarkably working process, reduced test cost and improved reliability and accuracy of the results. Taking the highest Al2O3 content 20 wt.% that is possibly attained in China at the present as an example, it is revealed by this work that CaO/SiO2 ratio should be regulated between 1.20 and 1.30 and MgO content should be controlled at about 8 wt.%. Control of lower MgO content is favorable for the decrease of slag volume and coke rate. This concept has already been applied into the practical production of blast furnaces in Wuhan Iron and Steel Corporation (Group).

Firstly, the commercial thermodynamic software package FactSage was applied in the calculation of phase diagram from the view point of melting point for the definition of slag composition range at different Al2O3 content levels; secondly, the KTH melt viscosity model was used in viscosity at 1,450°C calculation for slag compositions proposed by FactSage; thirdly, slag specimen were prepared with Al2O3 content of 18 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.% for viscosity experiments based on analysis of the above theoretical calculation results; and finally optimization schemes were proposed of blast furnace slag composition at different Al2O3 content levels. This kind of research method with the combination of theory and experiment accelerated remarkably working process, reduced test cost and improved reliability and accuracy of the results. Taking the highest Al2O3 content 20 wt.% that is possibly attained in China at the present as an example, it is revealed by this work that CaO/SiO2 ratio should be regulated between 1.20 and 1.30 and MgO content should be controlled at about 8 wt.%. Control of lower MgO content is favorable for the decrease of slag volume and coke rate. This concept has already been applied into the practical production of blast furnaces in Wuhan Iron and Steel Corporation (Group).

Keywords

Phase diagram calculation; Viscosity calculation; High alumina blast furnace slag; Properties optimization.

Phase diagram calculation; Viscosity calculation; High alumina blast furnace slag; Properties optimization.