Interface interaction between SiO 2 and magnetite under high temperature: particle migration and inhibition mechanism

Silicon is one of the main gangue components in iron ore, usually in the form of quartz and olivine. Numerous studies have shown that SiO 2 has a two-sided effect on the consolidation of pellets during high-temperature oxidation roasting of magnetite. However, it is very difficult to capture the structural evolution and migration mechanisms during high-temperature roasting process by existing experimental methods. Therefore, the influence of SiO 2 on the consolidation behavior of magnetite was studied through a series of roasting experiments and molecular dynamic simulation. The results show that the consolidation index and particle growth index decrease with the increase in SiO 2 content in the particles. At 1573 K, the liquid phase promotes the recrystallization growth of hematite at high temperature. Molecular dynamic study shows that it is difficult for quartz SiO 2 to form sintering neck with Fe 2 O 3 . When the calcination temperature is higher than 1400 K, the Fe 2 O 3 –Fe 2 SiO 4 system produces a considerable sintering neck structure after relaxation. The atomic migration ability of Fe 2 SiO 4 is much higher than that of Fe 2 O 3 . The higher atomic migration ability of Fe 2 SiO 4 is the main reason for the formation of the sintering neck.