SINTERING PLANT (Pakistan Steel).
Sintering is the agglomeration of fines of iron ore, manganese ore, coke breeze, limestone and dolomite along with recycled metallurgical wastes mineral particles into a lumpy porous mass by heat of combustion of fine coke added within the mass itself.
This agglomerated or lumpy mass combines efficiently in the Blast furnace charge and allow more consistent and controllable iron manufacture.
Pakistan Steel’s sintering plant is comprised of two sintering machines. Sintering Machine is a ( 4 meter wide and 100 meter long ) continuous circulating heat resistant steel belt (made up of 92 pellet cars or wagons linked together).
To obtain a desired product chemistry, the proportioned raw materials are obtained from 12 bunkers, sided in 2 rows which are mixed and moistened in a mixing drum. Then the raw material is passed through the shuttle conveyor into the hopper where it drops into the baling drum for mixing. The material bed depth over the grate is kept constant by adjusting the cut-off plate which is fitted with probes to sense the depth of material and automatically vary with the roll feeder speed.
The raw mix is ignited by the ignition hood, fuelled by a mixture of coke oven gas, blast furnace gas and sometimes natural gas. The carbon in the charge burns to raise the temperature (1150-1200 °C ) with the aid of the air sucked through wind box situated under the grate by means of blower fans at the bottom of sintering machine.
Burn-through area where the sintering material is completely fused and combined by the heat of combustion of coke fines to form an agglomerate. On completion of sintering process, the sintered agglomerate is crushed by passing it through a spiked roll crusher and cooled in the rotating circular cooler. The cooled sinter is screened where sizes up to -20mm size are returnd back to the sintering plant for reprocessing and sizes +20mm diameter are sent to the discharge bunker and finally transported to the Blast Furnace stock house through conveyor belts for preparing the Blast furnace burden (B.F. Charge material).
Therefore Sintering Plant plays an important role in converting ore fines ( which may be the part of shipments of iron ore & coal or result of in plant handling of raw materials or metallurgical waste generated within steel plant ) into lumpy fused material chargeable in blast furnace and hence thereby helps in reduction of coke consumption and enhance the productivity of Blast furnace operation by reducing waste.