For the majority of the twentieth century, the dry grinding circuits for that production of completed cement from cement clinker include two-compartment tube mills and the air separators. It isn't uncommon to deliver the cement in an open circuit. Advances in cement grinding engineering is slow and these advances are limited to more developed countries.
Efficient closed-circuit systems, because of their tight particle size control, lead to cements with relatively narrow particle size distributions (i.e. for a given mean particle size, they have fewer large and small particles). This is of advantage in that it maximizes the strength-production potential the clinker, because large particles are inert. As a rule of thumb, only the outer 7 ¦Ìm "skin" of each particle hydrates in concrete, so any particle over 14 ¦Ìm diameter always leaves an un-reacted core. However, the lack of ultra-fine particles can be a disadvantage. These particles normally pack the spaces between the larger particles in a cement paste, and if absent the deficit is made up with extra water, leading to lower strength. This can be remedied by including 5% calcium carbonate in the cement: this soft mineral produces adequate ultra-fines on the first pass through the mill.
All the raw materials are crushed with the help of Jaw Crusher if they contain lumps. The feed size for the Cement Mill should be less than 25 mm The raw materials are fed into their respective hoppers with the help of Belt Conveyor Or elevators. The hoppers are fitted with feeding systems which are connected with auto measuring and control system(Weighing Trolley). The measured quantity of raw material is discharged on a weighing Trolley/ conveyor belt. The weighing trolley/ conveyor belt carry the mixed material to the discharge hopper. The material from discharge hopper is taken to the elevator to feed into the Mill feed hopper. The discharge of the feed hopper is controlled by an adjustable speed rotary feeder. The feed of the mill can be varied as per the requirement. The rotary feeder discharge the material in to the Cement Mill. There are three chambers in the Mill. The chambers are filled with grinding Media ( balls & Cylpebs). The material is ground fine ( 3500 Cm2/gm.). The cement is discharged from the mill to the elevator to fill it in the Storage / Aeration Silo. The silo is fitted with compressed air coils. The air cools down the cement in the silo. The final product is tested from the bags for the quality and quantity and other parameters as per the statutory requirements provided by the Government.