Abstract：As one of the main components in slag, Al2O3 has a particularly prominent impact on the metallurgical properties of slag. For blast furnace ironmaking, the increase of Al2O3 in blast furnace slag will have an adverse impact on ironmaking and desulfurization. However, with the continuous development of China's iron and steel industry, the use of relatively low-cost high Al2O3 imported iron ore is increasing, which makes the content of Al2O3 in blast furnace slag significantly increase compared with the past. The mass percent of Al2O3 in blast furnace slag often exceeds 15%, and even higher can reach more than 20%. At present, there are few reports on the thermodynamic properties of Al2O3 components in high Al2O3 blast furnace slag system (for example, the measurement of Al2O3 activity by reference slag method) and their influence on the metallurgical properties of metallurgical slag, and temperature is one of the important thermodynamic factors affecting the metallurgical properties of metallurgical slag. Therefore, to explore the effect of temperature on the Al2O3 activity in metallurgical slag not only has important academic research significance, but also provides a solid theoretical basis for field practice. Thus, the activity of Al2O3 in CaO-SiO2-Al2O3-MgO blast furnace slag system at 1 773-1 873 K is measured by reference slag method, and the structure of slag is detected by Raman spectrum. The effect of temperature on Al2O3 activity of CaO-SiO2-Al2O3-MgO blast furnace slag system was investigated. The results show that with the increase of temperature, the chemical potential of Al2O3 in slag decreases, and the reaction between slag and Cu molten metal moves to the right to reach a new equilibrium. Therefore, the activity of Al2O3 decreases gradually with the increase of temperature. With the increase of temperature, Al2O3 in the slag reacts with alkaline metal oxides, increasing the formation of complexes such as calcium aluminate (CaO·Al2O3 and CaO·2Al2O3) and magnesium aluminate (MgO·Al2O3). At this time, the structure of the slag gradually depolymerizes due to the increase of O2-, and the free Al2O3 in the slag decreases, which cause the Al2O3 activity decrease gradually.
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2022, Vol. 57 
