Grinding Process Important Formulas ( Updated & Complete )
Internal volume of mill
Critical Speed of Ball mill
Ball size calculation
Mill Charge volume
Grindability determined according to Hardgrove
Hardgrove’s grindabilty index is based on Rittinger’s first law of grinding.
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)
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.
The hardgrove index H may be calculated on the basis of the weight D of the material passing a 74 micron sieve.