Utilization of micro-fines in sinter making and its implications on bed permeability and sinter quality

ABSTRACT Exploiting low-grade resources and raw material fines is a challenge for metallurgists developing new technologies. Iron-bearing and carbonaceous by-products are generated by ironmaking and steelmaking units and fed into the sinter plant. These by-products, which have varying proportions of ultra-fines, balling properties, moisture retention capacities, and so on, have a significant impact on sinter quality when used in sinter green mixtures. This study investigates the use of micro-fines and how it affects sinter quality while keeping operational factors such as moisture addition, balling index, and bed permeability in mind. In addition, the ideal moisture addition is investigated using higher micro-fines bearing dusts/sludges of various iron-bearing materials. The presence of columnar SFCA (Silico-ferrite of Calcium and Aluminium) is revealed by microscopic examination of the sinter produced with higher micro fines and good permeability, which improves the Reduction Degradation Index. It was also demonstrated that using more micro-fines in the blend and maintaining consistent moisture addition reduced the amount of return sinter produced.