Influence of a three-layered coke breeze distribution scheme on the iron ore sintering performances

The heat accumulation effect of the iron ore packed bed leads to uneven temperature distribution within the iron ore sintering process. This causes the under-sintering and over-melting of the sinter, reducing its performance. To address this issue, a three-layered coke breeze distribution scheme was proposed. Nine cases were designed, and their transient sintering processes were simulated to explore their influence on the sintering performances of the iron ore. The results show that directly increasing the coke breeze ratio of the upper layer can raise the peak temperature and melt quantity index (MQI) of the entire layer while reducing the cooling rate of the upper layer, but it will increase the risk of over-melting. Keeping the total coke breeze ratio constant, reducing the coke breeze amount in the top layer, and increasing the coke breeze ratio in the upper layer has a minor impact on the peak temperature, but it will lead to a faster sintering rate, which in turn causes a decrease in the MQI and an increase in cooling rate. Keeping the total coke breeze ratio constant and shortening the thickness of the upper layer while increasing its coke breeze ratio has a minimal impact on the sintering performance. Keeping the total coke breeze ratio constant and lowering the coke breeze ratio in the lower layer while increasing it in the upper layer is the most effective method to optimize the sintering performances. It can effectively raise the peak temperature and MQI in the upper layer while reducing its cooling rate. Besides, the heat generated by the upper layer can be effectively transmitted to the lower layer, so the peak temperature, MQI, and cooling rate of the lower material layer are less affected by its reduced coke breeze ratio.