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

The influence of ammonia and Brown gas injection on the iron ore sintering characteristics was explored through sintering pot experiments based on biochar substitution to increase biochar substitution proportion and reduce fossil energy consumption. 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. The research results provide an effective solution for low-carbon sintering.