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Ball Mills |
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Ball mill is an efficient
tool for grinding materials like ores, chemicals, ceramic raw
materials , paints etc. in to fine powder or fine paste by
grinding in a wet way. The Ball Mill operates by rotating a
cylinder with grinding balls like steel, CI, ceramic and pebble
balls as grinding media. Material fed through the mill is
crushed by impact and grounded by attrition between the balls
and also the internal cascading effect reduce the material in to
a fine powder. Ball Mills usually have liners inside which are
replaceable when they wear. Liners will be of wave shape which
key the ball charge in to the shell and prevent the slippage.
The rotation of the powder mixer is usually between 4 to 20
revolutions per minute, depending upon the diameter of the mill.
The larger the diameter is, the slower the rotation will be.
Ball Mills are generally used to grind material ¼" and
finer, down to the particle size of 20 - 75 microns.
To achieve reasonable efficiency, the ball mills are to be
operated in a closed system, with oversize particles
continuously being re-circulated back to the mill and to be
reduced
Types : Cylindrical Single /
Multi compartment with classifier and without classifier.
Conical cylindrical with classifier.
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Cylindrical Ball Mill |
Single / Multiple
Compartment Cylindrical Ball Mill
Single compartment Mill is a conventional type of batch mill,
consists of cylindrical steel shell with flat steel ends welded to
shell. Ball Mill rotates around a horizontal axis partially filled
with raw materials to be ground plus the grinding medium. The
material and the grinding medium are fed and discharged through an
opening manhole on the cylinder shell. Ball Mills usually have
replaceable liners inside and replaced when they wear out. Material
fed through the mill is crushed by impact and grounded through
attrition between the balls
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Technical Data
| Size Dia x L, ft |
Max. Ball Load lb. |
Motor HP |
Normal RPM |
Cement clinker
From 97%
<200 - m To
95% < 325 -
m bbl / hr. (a) |
LimeStone
from
<12.m to 95%
< 100m t.p.h. (b) |
Calcined
Gypsum to 95%,
100m t.p.h. (c)
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| 4 x 10 |
8.500 |
50 |
28 to 30 |
9 |
2 |
2 |
| 4 x 18 |
15.300 |
100 |
28 to 30 |
17 |
5 |
4 |
| 5 x 22 |
36.000 |
200 |
25 to 27 |
37 |
10 |
9 |
| 6 x 24 |
70.000 |
350 |
22 to 24 |
65 |
17 |
16 |
| 7 x 26 |
102.000 |
500 |
20 to 22 |
95 |
25 |
23 |
| 8 x 30 |
180.000 |
900 |
18 to 20 |
170 |
45 |
42 |
| 9 x 30 |
223.000 |
1200 |
16 to 18 |
235 |
65 |
60 |
| 10 x 30 |
278.000 |
1500 |
15 to 17 |
280 |
80 |
74 |
- Closed-circuit with air classifier. Product size equivalent to
1.750 to 1.800 cm²/gm
- Open circuit ; moisture less than 0.5%, average grind ability
- Feed temperature , 200° to 300°F - Open circuit
operation
Conical Ball Mill
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Conical Ball Mill
The Conical Ball Mill is most efficient when compare with
cylindrical mill. Classification and circulation within the mill is
the principle of operation for the conical mill. In a cylindrical
mill most of the work is accomplished in only a portion of the mill
cylinder length and the end corners are in effective. In conical
ball mill it is maximum utilization. More over the structural
advantage of a cone are well known. The truss is the strongest type
of structure. The conical ball mill is built on this structurally
sound principle. Minimum shell surface per unit of grinding volume,
less liner weight and thereby reduced dead weight load of the mill,
less bearing friction loss and over all power consumption,
classification are added advantages.
Conical Ball Mill a closed circuit system incorporate the
classification system comprising the Rotary Classifier, Dynamic
Classifier, Multi cyclone & Bag Filter
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Layout of Conical Ball Mill |
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Technical Data
| Mill dia. ft X
cylinder Length in |
Ball Load lb
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RPM |
Motor HP |
CAPACITY t.p.h. |
| Lime stone |
Cement clinker |
Chrome ore From
<¾" to 97% <200. m.
(e) |
Ilmenite Sand
From <40.m To 98% <200.m.
(f) |
From <¾" to
99% <20. m.
(a) |
From <3/8" to 90% <200.
m.
(b) |
From <1" to 99% <20.
m.
(c) |
From <20.m to 95% <325.
m.
(d) |
| 4½ x 16 |
3,800 |
30 |
20 |
1.6 |
1.0 |
7.0 |
3.1 |
0.67 |
0.44 |
| 5 x 22 |
6,700 |
28 |
40 |
3.3 |
2.0 |
1.5 |
7.3 |
1.1 |
0.90 |
| 6 x 22 |
11,100 |
26 |
60 |
5.7 |
3.5 |
2.8 |
13.0 |
1.9 |
1.50 |
| 7 x 22 |
17,000 |
24 |
100 |
9.0 |
5.2 |
43.0 |
18.0 |
2.8 |
2.20 |
| 3 x 36 |
32,000 |
21 |
150 |
15.0 |
9.7 |
80.0 |
35.0 |
5.2 |
4.10 |
| 9 x 48 |
50,000 |
19 |
300 |
30.0 |
19.0 |
150.0 |
68.0 |
10.5 |
8.00 |
| 10 x 66 |
65,000 |
18 |
400 |
43.0 |
26.0 |
215.0 |
94.0 |
14.0 |
11.00 |
| 12 x 60 |
105,000 |
17 |
700 |
70.0 |
43.0 |
360.0 |
150.0 |
23.0 |
19.00 |
| 12 x 120 |
170,000 |
16 |
1200 |
120.0 |
80.0 |
650.0 |
270.0 |
40.0 |
38.00 |
- Closed circuit with vibrating screen ; product will contain 38 to
42% <200.m
- Closed circuit with air classifier; Fan power is 4 to 5 hp/ton.
- Closed circuit with vibrating screen classifier ; product will
contain 35 to 40%<200. m.
- Closed circuit with classifier ; fan power 2 to 2.5 hp per bbl.
- Chrome ore pre-dried; crushes readily but hard to grind ; add 6
hp/ton for air classifier fan power.
- Very hard. Closed circuit with air classifier requires 9 hp/ton
additions.
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