Variable Activation Energy Models for the Shrinkage and Softening Melting Behavior of Iron Ore in Blast Furnace Conditions.

Understanding the shrinkage behavior of iron ore is crucial for achieving blast furnace (BF) operating efficiency and reducing fuel ratio. This study presents high-temperature reduction load experiments on iron ore, simulating BF conditions. Two new shrinkage behavior models (SAEM-PC and SAEM-S&M) were established by combining the effects of temperature and reduction. These models describe the dynamic relationships between the temperature, reduction degree, and the physical properties of iron ore such as density and apparent viscosity during the reduction process. The activation energies ( for the PC stage and for the S&M stage) were determined to range from 79.95 to 42.69 kJ/mol and from 68.74 to 2.51 kJ/mol, respectively. The demonstrates a gradual decrease, indicating a weakening of contraction resistance with temperature rise and reduction progress, while exhibits fluctuations due to the interplay between the formation of liquid slag and the generation of solid sponge iron. The predictive accuracy of the model is substantiated by its average deviations. This study can deepen the understanding of the shrinkage mechanism of iron ore, which is of great significance for enhancing energy efficiency and reducing emissions in the steel industry.