Analysis and Modeling of Iron Ore Reduction and Melting Behavior under Blast Furnace Ore-Coke Coupling Conditions

The efficiency of blast furnace (BF) ironmaking, a predominant method for pig iron production, is profoundly influenced by the reduction-contraction behavior and melting reduction mechanism of iron ore within the cohesive zone. These factors are critical for optimizing BF operations and energy utilization, yet remain incompletely understood, particularly under ore-coke coupling conditions. This study introduces a novel methodology to investigate the complex interactions between iron ore and coke, focusing on oxygen and carbon transfer during high-temperature reduction processes. Results demonstrate that the contraction rate of the iron ore layer is positively correlated with the direct reduction rate prior to melting, whereas inversely related trends emerge during the melting process. Postmelting, the contraction rate is governed by the dripping behavior of slag and molten iron permeating through the coke layer. The melting reduction mechanism is delineated into two distinct stages: the initial stage involves direct reaction between FeO and coke, while the subsequent stage is characterized by carbon monoxide production from the reaction of coke with CO2, which subsequently permeates into the iron layer, establishing a gas film (CO and CO2) at the coke-iron interface. This research provides fundamental insights into the thermal behavior and modeling of iron ore reduction and melting in BFs, offering a robust theoretical foundation for enhancing iron ore and coke utilization efficiency while reducing carbon emissions.