Establishment and industrial practice of high-temperature process evaluation system in sintering

The behaviors of typical iron ores at high temperature were observed by confocal scanning laser microscopy. Four critical temperature points and liquid flow velocity at high temperatures of iron ores were obtained and the temperature points contain temperature at which sample starts to shrink, temperature at which the initial liquid phase forms, temperature at which a lot of liquid forms and temperature at which liquid consolidation ends. Under the same CaO to Fe₂O₃ ratio, the liquid phase fluidity of iron ore fines of Carajas (IOC) is good. However, under the same basicity, as the content of SiO₂ in IOC is low, the liquid phase fluidity of IOC is much smaller than that of Yandi fine. After analysis of the initial formation and development of the liquid phase and the final consolidation process, the high-temperature process evaluation system (HTPES for short) of iron ore was established. The idea of “dense ore matching fusible ore” instead of “relatively fusible ore” was proposed based on the results of HTPES and applied in ore matching of a sinter plant from Shougang Jingtang. The use of IOC (13–18%) instead of standard sintering fines (SSF) improved liquid phase fluidity and ensured the sinter quality. Furthermore, the use of IOC fine (18–23%) with Hainan fine (0–2%) instead of SSF, a mixture of hematite and Marra Mamba ore and concentrates guaranteed the quality of sinter ore through improving fluidity, in the meantime reducing ore matching costs. With the establishment and application of HTPES, the sinter plant has achieved good economic benefits under the premise of ensuring the quality of sinter ore.