L = Internal length of the mill in cms. after lining.
2. For continuous type ball mill :
M = 0.000503 x D2 x L
Example - To calculate grinding media charge for a steatite ceramic lined batch type mill size : Dia 6' x 6' Long (Dia 180 cm x 180 cm L) (mill openings are not considered).
To calculate the motor power required for a cylindrical type ball mill, the following formula can be applied :
W = 0.04116 x D3 x L x n x (0.6d + 0.4d1)
where :
W = Required motor power in HP
D = Internal dia of the mill in mtr
L = Internal length of the mill in mtr
d = Specific gravity of grinding media
d1 = Specific gravity of substance
n = Speed of ball mill in rpm.
Example - 1: Let the internal dia of the mill be 1.8 mtr and internal length be 1.8 mtr. If Alumina grinding media is used density d = 3.6. If milling substance is alumina in slurrry form with around 70% solids then d1 = 2.0
Therefore
W = 0.04116 x (1.8)4 x 19 (3.6 x 0.6 + 2 x 0.4) = 24.3 HP
Example - 2: If Steatite grinding media are used to mill the glass frit
d = 2.65 and d1 = 1.6 then,
W = 0.04116 x (1.8)4 x 19 x (2.65 x 0.6 + 1.6 x 0.4) = 18.3 HP
To calculate the speed of the mill, use the following formula:
