chapter - 1 introduction - Meghalaya State Pollution Control Board

Hills Cement Co. Limited.
6.1. RAW MATERIALS PREPARATION
1. Efficient Transport Systems (Dry Process) - Transport systems are
required to convey powdered materials such as kiln feed, kiln dust,
and finished cement throughout the plant. Mechanical conveyors use
less power than pneumatic systems & the average energy savings are
estimated at 2.0-kWh/tonne raw materials with a switch to mechanical
conveyor systems. Conversion to mechanical conveyors is costeffective
when replacement of conveyor systems is needed to
increase reliability and reduce downtime.
2. Use of roller mills (Dry Process)- Traditional ball mills used for grinding
certain raw materials (mainly hard limestone) can be replaced by highefficiency
roller mills, by ball mills combined with high-pressure roller
presses, or by horizontal roller mills. The use of these advanced mills
saves energy without compromising product quality.
3. High-efficiency classifiers/separators- A recent development in
efficient grinding technologies is the use of high-efficiency classifiers
or separators. Classifiers separate the finely ground particles from the
coarse particles. The large particles are then recycled back to the mill.
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