Sinter is produced from fine raw ore, small coke, crushed sand-sized limestone and numerous other steel plant waste materials that contain some iron. The fine materials are proportioned to obtain a desired product chemistry then mixed together (using a boom stacker). They are blended using a boom in horizontal layers of appropriate thickness to give the correct blend on a 800m long ore bed (See diagram below). It is important to mix the right ores together in the right proportion to get a suitable mix for the blast furnace.
Before being delivered to the sinter machine, the ore mixture is moistened to cause fine particles to stick to larger ones, and then the appropriate amount of coke is added.
Recycled iron-bearing materials are also added at this stage. A reclaiming rake removes a cross-section of this pile of layers and carries it to the sintering plant.
Large amount of coal are needed which are converted to coke by heating in the absence of oxygen. The granulated coke is feed into the sinter plant along with along with the ore where they are sintered or heat treated.
The iron ore, pellets and sinter then become the liquid iron produced in the blast furnace with any of their remaining impurities going to the liquid slag.
