Sinter strength evaluation using process parameters under different conditions in iron ore sintering process

There exists internal connection between the process parameters and real sinter quality in the sintering process. However, few investigations on bridging the process parameters and real sinter quality for engineering applications were reported. For example, only process parameters (flow resistance, heat condition of sintering bed and off-gas composition) can be obtained by numerical method in the previous studies. Actual sinter strength and reducibility can’t be captured due to lacking of reliable models and the limited computing resource. This paper focused on solving the problem, which was substantial for parameters optimizing in both numerical simulation and on-line control of sinter quality. The melt quantity index (MQI), combining the peak temperature and duration time of melting temperature (DTMT), was used in this study. We also explained its physical significance as the effective “energy” for melting phase formation. Then the corresponding relation between MQI and sinter yield was widely confirmed by our own experimental data and the reproduced data from published references. Consequently, the MQI was recommended as a wise indicator of real sinter strength. The effects of three operating parameters (fixed carbon content, sintering pressure and fuel reactivity) on sinter strength were investigated by examining the MQI, sintering speed and air flowrate. Besides, the influencing mechanism of two important performance parameters (combustion and heat utilization efficiencies) on MQI was clarified. The monitoring of the above parameters would provide a powerful support for the transparency of sintering process “black-box” and optimization of operating parameters. Finally, a conceptual design for the on-line control of sinter strength was even proposed based on the present results.