To download the below  and all other Useful Books and calculations Excel sheets please click here 

To download the below  and all other Useful Books and calculations Excel sheets please click here 

Grinding Process Important Formulas ( Updated & Complete )

Internal volume of mill

Critical Speed of Ball mill

Ball size calculation

Separator efficiency

Mill Charge volume

Grindability determined according to Hardgrove

Hardgrove’s grindabilty index is based on Rittinger’s first law of grinding.
Equipment
Grinding bin, with 8 balls (D 25.4 mm)
Grinding ring activated by 0.2 kW motor
Ring load on bin approx. 29 kg
Sample: 50 g (590 < x < 1190 microns)
Test procedure
50 g of the material, with a particle size limitation of minimum 590 microns and maximum 1190 microns, is prepared and placed in thegrinding bin.
After 60 revolutions, the ground material is taken out of the bin and theweight of the material passing a 74 micron sieve is determined.

Sample evaluation

The hardgrove index H may be calculated on the basis of the weight D of the material passing a 74 micron sieve.