Influence of ammonia and Brown gas injection on the iron ore sintering characteristics under biochar substitution

By dividing the high-temperature stage of the sintering bed, the heating rate and cooling rate were calculated, and the reasons for poor sintering quality under a high biochar substitution ratio were explored.

The results showed that under the 40% biochar substitution ratio, the cooling rate of the sintering bed significantly increased, the high-temperature duration time was short, and the sintering quality deteriorated severely. Additional injection of 0.5–1% vol ammonia or 1–2% vol Brown gas can reduce the cooling rate, prolong the high-temperature duration, and optimize the sintering quality. Based on 1% vol ammonia or 2% vol Brown gas injection, reducing the proportion of biochar with equal calorific value further increases the sintering comprehensive index, which means that using 1% vol ammonia or 2% vol Brown gas injection to assist sintering can reduce the proportion of coke usage to 60%, while the proportion of biochar substitution is 33.76% and 32.47%, respectively.