Development of Pellet-Sinter Composite Agglomerate for Blast Furnace

Abstract

Microfines of iron ore are generally utilized in Blast furnace in form of indurated pellets because sinter bed has limitation of accepting fines. Charging of acid pellets with basic sinter is the normal practice in blast furnace. However induration of pellets is very cost intensive. Further more, due to low angle of repose pellets distribution during charging with other materials in blast furnace creates inhomogeneous distribution. In order to alleviate the above problem, a composite mass of acid pellet and basic sinter has been developed, wherein; green pellets made-up of microfines were mixed with basic sinter mix and sintered the combined mass in a sinter bed of 10–12 kg scale. A composite mass of indurated pellet and sinter named as ‘Pellet-Sinter Composite Agglomerate’ was obtained. Linz Donawitz converter sludge and mill scale were used in pellet mix to provide in-situ heat in pellets that enhances incipient fusion to form bond in pellets. The developed sinter shows good shatter index (92%), tumbler index (67.5%) abrasion index (7.5%) and reducibility index (70%) and low reduction degradation index (27%), which are comparable with the conventional iron ore sinter made in the same set-up keeping other condition identical. This innovative technique help improving 30% microfines utilization in sinter bed, reduce coke breeze/energy consumption, reduce overall basicity of sinter and decrease flux composition.