08-16-2017, 09:33 PM
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PRODUCTION DEPARTMENT
I was in production department, I Shaw and understood various processes to make clinker and cement. Main reaction process occurs in kiln at 1400 C to make clinker. To make cement grinding and rubbing processes take in cement mill. Main process is as below:
MINING:
They have two types of mining process: Conventional mining (Blast mining) and Eco-friendly surface mining. In blast mining, Drill a hole with the help of drilling machine and fill the explosive material into that hole, allow exposing and it will take limestone from earth. Second one is the surface mining. In the mining surface miner is used to extract the limestone from earth. Blast mining is dangerous for surrounding village because it creates shock. They have very rich captive mines. Two mines actually they have one is morasa mines and other ones is prasanavada mines. In this mines almost all grades of limestone is available and a very little quantity of additive is to be added from outside to prepare raw-mix.
CRUSHING:
The mined limestone is hauled through Dumpers to a rotary hammer - impact type crusher that crushes the limestone to a size of 80% up to - 75 mm size. Additive material is added to the crushed limestone through an additive hopper, which bypasses the crusher.
STACKING:
The material is passed on to the stacker via belt conveyors, which stacks the material in longitudinal layers. To perform this function they have chevron-stacking stacker, which was supply by Elecon Company.
RECLAIMING:
They having end reclaim type reclaimer. The stacked material is lifted by the reclaimer, which reclaims it by cutting transversely the longitudinal stacked layers ensuring perfect blending and homogenizing. The reclaim material is transported to raw mill through belt conveyors.
RAW MILL GRINDING:
They having Atox-40 vertical roller mill. The desired material is drawn from lime stone reclaimer pile to the Box feeder and is fed to the vertical roller mill through chute. The vertical mill consists of a rotating table upon which 3 rotating rollers are hydraulically pressed. The material is dried and transported by the hot kiln exit gases. The size of the pulverized material is controlled by a static separator, which separates the oversized particles and sends it back on the table for further grinding. The pulverized material is transported to the C.F. Silo via energy efficient bucket elevators.
PROCESS IN C.F.SILO:
The pulverized material is stored and blended in the controlled flow silo. The blending action is achieved by extracting the material from the 7 outlets at a different flow rate. The extracted material is conveyed to a weighing bin were it is further blended. The operation of extraction is controlled by a PLC. The blended material is fed to the pre heater for preheating via bucket elevator.
PREHEATING:
Preheating process is done in the preheater and pre-calciner string having four stage cyclone. Approximately 40% of the total feed is given to the pre heater string where it get preheated by the hot kiln exit gases and gets calcined up to 30% approximately. The balance 60% feed is fed to the calciner string where coal is fired in the calciner and the 30% calcined feed from the pre heater string is also added to the calciner. Here, about 90% calcinations are achieved. Chemical formula of this process (at 900 C) is as under:
CaCO3 CaO + CO2
900
KILN PROCESS:
The material comes from ph and pc string is feed into the kiln where remaining 10% Calcinations process is done. This calcined feed is transferred to the kiln for the remaining 10 calcinations and sintering where the flux materials and silica melt and react with lime to form four clinker constituents. This is achieved by firing coal in the rotary kiln. Kiln capacity is 4000 TPD.
