Stages of Manufacturing Process

Traditional Process of Manufacture

Improvements in Modern Process of Manufacture

Stage I

Raw materials are reduced to the desired sizes by passing them through Primary & Secondary Crushers.

The stone reduces to about 5” (125mm) size after passing through Primary crusher & to ¾” (20mm) size after passing through Secondary Crusher. (Crushed) Raw materials are stored separately & are now ready for being conveyed to grinding mills.

Basically the same as Traditional process

Stage II

Raw materials are proportioned, ground in grinding mill & blended.

Either of the “Wet”, “Dry” or “Semi Dry” process can be adopted. Ground Raw material is now ready for being feeded to the kiln.

Grinding is done using Roller mill. Roller mill combines crushing, grinding, drying & classifying in one unit.

High-Pressure grinding rolls usually in conjunction with ball mills can also be optionally used (along with roller mill)

Only the dry process is adopted.

Stage III

Raw material is now fed to the kiln. Burning changes the raw mix chemically into cement clinker. Clinker & Gypsum are conveyed to the grinding mill

Hot gases from kiln heat raw feed in the pre-heater (four stage) & provide 40% calcination before feed enters kiln. 

Some installations include a Flash Furnace that provides about 85-95% calcination before feed enters kiln.

The kiln length is lesser due to these improvements.

Stage IV

Clinker with Gypsum is ground into Portland Cement, packaged & stored/shipped.

Twin High pressure roll press to precrush clinker entering the ball mill, High efficiency Dust Collectors & High efficiency Separators are used