Mathematical Model Study of the Process Kinetics during Roasting of Iron Ore Pellets

A mathematical model of the kinetics of the redox reactions in a layer of iron ore pellets is developed. The kinetic equations relating the completeness of the redox reactions to the heat treatment time and temperature and to the gas phase composition are the major component of the mathematical model. The model is applied to determine the optimum conditions of roasting pellets in OK-228 conveyor machines. An algorithm is developed to calculate the degree of oxidation of iron monoxide in the pellets situated at any point of the roasted layer. These parameters characterize the metallurgical properties of the pellets both in the initial state and upon reduction in a blast furnace. The methods for calculating the kinetic parameters used for the mathematical processing of the experimental data obtained on studying titanomagnetite oxidation and hematite dissociation on roasting of the Kachkanar pellets are considered. A rather high convergence of the calculated and experimental data is found: the error does not exceed 10–15%.