Development of Pellet-Sinter Composite Agglomerate for Blast Furnace

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.