Limestone rocks are sedimentary rocks that are made from the mineral calcite which came from the beds of evaporated seas and lakes and from sea animal shells. This rock is used in concrete and is an excellent building stone for humid regions.
Limestone Grinding Plant
The feed material is fed pneumatically through a venturi eductor into the mill. The particles are pulverized by a high speed agitated grinding media. The grinding media can be stainless steel, chrome steel, alumina or zirconia. The micronized particles are entrained in the air stream and exit the mill in a high efficiency air classifier. The on size particles are separated and the oversize returned to the mill for regrinding.

 

This grinding process is suitable for calcium carbonate, marble and limestone grinding down to 1 micron average particle size.

Limestone Grinding Control System
In a process not involving the liberation of a valuable mineral, such as in producing limestone for the scrubbing of flue gases from power plants, the control requirements could be as follows:

Control density of the classifier product.
Add Ball mill water at a ratio to the new feed rate.
Maintain a set feed rate.
Provide for intermittent operation.
The control circuit shown in below figure provides for these control requirements in this manner: 

Limestone Grinding Case in Belgium
As a material supplier for a paper making company, a factory from Belgium needs a mill to get limestone powder. The required output size is D90=105μm, required capacity is 3-5t/h. Since this client just needs medium output size, our MTM Medium Speed Trapezium Mill will be suitable for him; and the required capacity is low, so the small model MTM100 is his best choice. Under guidance of our engineer, they have finished the installation and commissioning. The classifier is adjusted for required size and the capacity has reach to more than 4t/h. Now the plant is running stably with good performance.