Effect of raw material composition on combustion behavior of quasi-particles in the iron ore sintering process

As the basic unit of iron ore sintering bed, the combustion behavior of quasi-particles significantly impacts the sintering process. Adding biomass char leads to the deterioration of sintering quality, which was originally for the reduction of carbon emission. In this study, the isothermal thermogravimetric platform was used to analyze the combustion behavior of quasi-particles using different fuels and ores. The results show that the mass of quasi-particles packed bed decreases rapidly with combustion, then rises slowly, and then tends to be stable. The quasi-particle samples in the combustion process were quenched with liquid nitrogen, and the composition changes in the quasi-particle combustion process were analyzed. The results show that the excessive mass loss is caused by the reduction of iron ore in the sintering atmosphere, which also means heat loss. Compared with the samples using coke, when the fuel is exhausted, the proportion of calcium ferrite in the samples using charcoal decreases by 10.94%, while the proportion of magnetite and FeO is 11.36% and 1.04% higher, respectively, which will further lead to the formation of calcium iron olivine and reduce the sinter strength. The addition of magnetic concentrate may help to reduce the heat loss caused by the reduction reactions, but it is necessary to optimize the sintering process.