Recent developments in iron ore sintering. Part 4. The sintering process

The major developments around the sinter strand are in four areas: (i) energy consumption, (ii) productivity, (iii) process control, and (iv) environmental control. Significant reductions in energy requirements have already been achieved as a result of installing heat recovery systems, improved ignition, decreasing air leakage, improved raw materials characteristics, and improved fan control. Increased productivity is achieved by maximising the yield of sinter product. This is influenced by factors such as uniformity of sintering both horizontally and vertically in the bed, sinter bonding strength, crushing of the sinter product, and selection of screen aperture for return fines. Other factors such as bed depth, size distribution of coke breeze, ignition, plant availability, and oxygen enrichment may also have an effect on productivity. The latest plant control systems are based on artificial intelligence and their use is spreading. The main emissions from sinter plants are dust, sulphur oxides, and nitrogen oxides. Many plants have installed electrostatic precipitators to control particulate emissions and can achieve levels below 50 mg/Nm3. Desulphurisation equipment has been installed at about half of the operating plants in Japan but at only one plant in Europe.