Download - Ball Charge Design
Ball Charge Design Methods
Grinding Course
Ball Charge Design Methods
• Polysius for Finish Mills A formula that covers the entire mill as though it is a
single compartment mill.
• Slegten For Finish Mills Rules for 1st Compartment and “Transition Zone” Formula for Remainder of 2nd Compartment
Polysius Ball Charge for Finish Mills
xeD 13.96
D = Ball Diameter , mm
X = Distance From Feed End of Mill, m
Polysius Ball Charge Design
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
110.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Distance From Feed End of Mill, m
Bal
l Dia
met
er, m
m
Ball Sizes
0.6250.6316
0.750.7920
10.9825
1.251.1830
1.51.5740
21.9750
2.52.3660
2.752.7670
33.1580
3.53.5490
approx std size, inchBall Dia, inchBall Dia.,mm
Example of Polysius Ball Charge
100.00 100.009.5Total C2
0.0049990.0000.625
32.33495531.5830.75
0.0048860.0001
31.53483231.5831.25
15.62478815.791.51.5
20.52471821.0522
0.5Partition
100.00 100.004Total C1
25.00450025.0012.5
25.00450025.0012.75
25.00450025.0013
25.00450025.0013.5
% by wt.Bulk Density,
kg/m3% by VolMill Length,mBall Dia, in
Slegten Ball Charge For Finish Mills
• Use 90 mm Balls for 20% (by wt.) of 1st Compartment Charge.
• Use Same number (“n”) of 80,70, and 60 mm Balls for Remainder of 1st Compartment Charge.
• Use “n” number of 50 and 40 mm Balls in 2nd Compartment. (Transition Zone)
• Fill Remainder of 2nd Compartment According to:
• D = Ball Dia., mm
• X = Distance from Transition Zone, m
xeD 1.33
Slegten FM Ball Charge Design For Fine Grinding Zone
y = 33e-0.1x
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6 7 8
Distance From End Of Transition Zone, m
Bal
l Dia
., m
m
Compartment 1 - Polysius vs Slegten
Ball Charge Comparison,1st Compartment, 4m Dia by 4 m Length
0.0
10.0
20.0
30.0
40.0
3.5 3 2.75 2.5
Ball Sizes, inch
% o
f 1s
t C
om
par
tmen
t C
har
ge
Mas
s
Polysius
Slegten
Compartment 2 - Polysius vs Slegten
Ball Charge Comparison, 2nd Compartment, 4m Dia. By 9.5 m Length
0.00
10.00
20.00
30.00
40.00
2 1.5 1.25 1 .75 .625
Ball Size, inch
% o
f 2nd
C
om
par
tmen
t C
har
ge
Mas
s
Polysius
Slegten
Slegten vs Polysius
Comparison of Slegton and Polysius Ball Charges
00.5
11.5
22.5
33.5
4
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Distance From Mill Feed End, m
Bal
l d
iam
eter
, In
ch
Slegten
Polysius