Effect of ammonia injection stages and segregation degrees on the characteristics of iron ore sintering process

To reduce solid fuel consumption and carbon emissions during iron ore sintering, ammonia injection-assisted sintering was proposed, and its feasibility was verified through sinter pot experiments. The effects of ammonia injection stages and segregation degrees on the sintering characteristics were investigated based on the uneven heat distribution in the sintering bed. The results show that ammonia injection improves fuel combustion efficiency, sinter bed temperature and melting quantity index. The sinter ore strength and yield were improved, and the effect of injecting ammonia in the early sintering stage was more significant. When the ammonia injection segregation degree is 0.042 %/min, the sinter ore yield and tumbler index increase from 61.93% and 49.4% to 68.85% and 58.8%, respectively, the average fuel combustion efficiency increases from 89.02% to 92.30%. When the segregation degree increases from 0 to 0.125 %/min, the standard deviation of the uniformity coefficient of the high-temperature index first decreases and then increases, reaching the minimum value when the segregation degree is 0.042 %/min. A segregation degree of 0.042 %/min can achieve the most uniform heat distribution in the sintering bed and the best sinter ore quality, which provides a reference for applying ammonia injection-assisted sintering in industrial production.