Reaction mechanism analysis of the Al₂O₃ in blast furnace (BF) slag

Abstract

Al2O3 is one of the main component in blast furnace (BF) slag, which the reaction mechanism influence on the metallurgical performance directly in the process of the slag forming. In the paper, ΔGfθ was used to analyzed the slag formation reaction process of the Al2O3, at the same time, the phase diagram and activity were calculated by Fact-Sage with CaO - MgO – SiO2 - Al2O3 slag system, it can be found that the complete liquid phase region temperature is about 1 500°C and the content of the Al2O3 is 11%. Activity of CaO is stronger than the others, from which the liquid phase can be formed easily in the high temperature, meantime the reaction energy barrier between CaO and SiO2 is lower and stabilization of the product is better. By the high temperature experiment, a lot of Ca2Al2SiO7 was separated out with the high content of Al2O3 and slag basicity, as a result, the transformation of the solid phase to the liquid phase was effected by the constantly increasing the content of Al2O3 .

Keywords

• blast furnace
• Al₂O₃ content
• slag formation reaction
• crystallization
• melting temperature