Thermodynamic Study on Modification of Converter Slag by Using Hot Blast Furnace Slag

Blast furnace slag (BFS) and converter slag (CS) are the main by-products of the BF-BOF long-process steel production model. In China, the utilization ratio of BFS is high. CS cannot be widely used in the building materials industry due to its characteristics, which is an important issue for the sustainable development of Chinese steel companies. In this article, FactSage software is used to study the conversion of CS by using the heat of BFS, and the research results provide a theoretical basis for improving the utilization ratio of CS. The thermodynamic calculation results show that when the temperature is lower than 1200 ℃, the liquid phase ratio of the CS is higher than that of the BFS. When the temperature is higher than 1250 ℃, the liquid phase ratio of BFS is much higher than that of CS. When the mass ratio of BFS to CS is increased from 5:5 to 9:1, the liquid phase ratio of the mixed slag at the same temperature will gradually increase. The molten BFS can absorb the free CaO and MgO in the CS through a variety of eutectic phase and peritectic phase melting reactions, and melt part or all of the high melting point Ca₂SiO₄. When the proportion of BFS is relatively high, the fluidity of the mixed slag can be maintained, which provides a guarantee for subsequent processing.