Mathematical modeling of and parametric studies on flue gas recirculation iron ore sintering

A relatively more comprehensive 1D mathematical model, compared to previous models, is proposed for flue gas recirculation sintering (FGRS). The proposed model considers multiphase theory, eight major reactions significantly affected by the input gas conditions, and various heat transfer processes within/between different solid and gas phases. Characteristic size distributions of materials including coke, limestone and dolomite are used to correct the reaction rates of key sub-models, as well as specific kinetic parameters determined via thermogravimetric analysis instead of empirical values. Geometric changes caused by the reactive and melting factors are described in improved manners. This model is validated by contrasting the modeling results and the measured data from sinter pot tests. Parametric studies show FGRS technology can significantly enhance combustion characteristic within sinter bed, meaning to increase maximum temperature and melt fraction, improve the uneven distribution of heat. Therefore, the quality of sintered ore can be improved. However, the slightly reduced flame front speed deserves further attention. The velocity of input flue gas exerts the most significant effect, followed by O2 concentration, and then, temperature. The operating parameters of FGRS must be carefully determined. Three measures, which still require further investigations, can be proposed to optimize the process.