Mineralisation behaviour of iron ore fines in sintering bed with flue gas recirculation

Implementing flue gas recirculation brings changes to gas conditions across the sintering bed, significantly influencing the mineralisation behaviours. Compared with the conventional process, the O2 partial pressure of the sintering bed decreased while COx partial pressure increased, whereas the contents of bonding phases reduced, leading to an increase in porosity and the magnetite content in the product. Simultaneously, the reduction disintegration index of sinter products decreased owing to an increased in porosity. The phase development in roasted products showed that hematite and calcium ferrite were formed in the condensation and cooling processes while more magnetite and silicate were presented in the combustion and melting processes. Consequently, the sinter products with 30% flue gas recirculation ratio were qualified as conventional sinter.