Effect of Al_2O_3 on Low-Temperature Reduction Degradation of Iron Ore Sinter

摘要

Al-containing hematite solid solution and Al_2O_3-containing sintered sample were prepared and reduced at 550°C in 20%CO-20%CO_2-60%N_2 to investigate the effect of Al_2O_3 on low-temperature reduction degradation of iron ore sinter. The conclusions are obtained as follows. 1. The solid solution of alumina into hematite resulted in decrease of interplanar spacing, increase of bigger pores in sintering sample, and increase of transforming rate of hematite to magnetite obviously in reduction process, it revealed a main reason of the low-temperature reduction degradation of iron ore sinter with Al_2O_3. 2. The iron ore fines with Al_2O_3 could promote the formations of liquid phase and calcium ferrite in the sintering process, resulting the reduction rate of sintered sample decreased, it is conducive to improve the performance of low-temperature reduction degradation of iron ore sinter. 3. The calcium ferrite could be not reduced at 550°C in 20%CO-20%CO_2-60%N_2, it was deduced an effective way to restrain the appearance of low-temperature reduction degradation for sinter with Al_2O_3 that formation of calcium ferrite is promoted to decrease the hematite content in the sinter.