Mechanism of Selective Desulphurization in Iron Ore Sintering Process by Adding Urea

Iron ore sintering is an important part during the ironmaking process, and a large amount of SO2is also generated. Our previous research shows that it is an effective way to reduce SO2content of flue gas by adding urea to a special sintering material zone position. In this paper, the mechanism of selective desulphurization by adding urea during the iron ore sintering was carried out. The results show that 88.14 % desulphurization rate was obtained with the addition of 0.05 % urea particles at 100 mm height from the feed bottom. During the sintering process, when drying zone reached the added position of urea, large amounts of NH3were generated by urea decomposition, and then reacted with SO2to produce (NH4)2SO4in the wetting zone. With the accumulated desulphurization reactions during the sintering, the low SO2emission in the flue gas was achieved. Moreover, the addition of urea in the bottom zone avoided the ammonia present in the sintering ore and promoted the urea utilization efficiency.