The most important raw material needed to produce steel is iron ore. But, as is the case with coal, iron ore cannot be used directly in the blast furnace. That is why we first have to create sinter.
How does this work?
In our sinter plants (Ghent), we bake a mixture of fine iron ores, ferruferous recuperation materials and fluxes. This is done on a slow moving grid conveyor belt which uses coke breeze as its fuel.
The grid conveyor belt is a closed-off chain, composed out of conjoined grid cards. The spread-out layer of mixture is set on fire via the burners on top. While the grid conveyor belt is moving, the fumes are sucked away from the mixture via the fume exhaustion below. The mixture is thus baked from top to bottom. At the end of the line, the (now) sinter cake is discharged on a crash-deck, where it is crushed and cooled.
Sinter has the perfect chemical composition, grain size and physical attributes to be used in the blast furnace.
Sinter typically accounts for 90% of the blast furnace metallic burden. The remaining part of the burden consists of pellets and calibrated ore.