温度对CaO-SiO2-Al2O3-MgO高炉渣系Al2O3活度的影响

doi:10.13228/j.boyuan.issn0449-749x.20210450

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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 O^2-, and the free Al₂O₃ in the slag decreases, which cause the Al₂O₃ activity decrease gradually.

Key words： Al₂O₃ activity temperature enthalpy of dissolution slag structure Raman spectrum

Received: 04 August 2021

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	Articles by authors
	HU Xin-guang
	SHEN Feng-man
	ZHENG Hai-yan
	GUO Yong-chun
	JIANG Xin
	GAO Qiang-jian

Cite this article:

HU Xin-guang,SHEN Feng-man,ZHENG Hai-yan等. Effect of temperature on Al₂O₃ activity in CaO-SiO₂-Al₂O₃-MgO blast furnace slag system[J]. Iron and Steel, 2022, 57(4): 25-33.

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http://www.chinamet.cn/Jweb_gt/EN/10.13228/j.boyuan.issn0449-749x.20210450 OR http://www.chinamet.cn/Jweb_gt/EN/Y2022/V57/I4/25

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