Ball mill
Product description
The ball mill is the key equipment for crushing the material after it has been crushed. It is widely used in the production of cement, silicate products, new building materials 52555, refractory materials, fertilizers, black and non-ferrous metal dressings and glass ceramics. Dry or wet grinding of various ores and other grindable materials. . The ball mill is suitable for grinding various ores and other materials. It is widely used in mineral processing, building materials and chemical industries. It can be divided into dry and wet grinding methods. According to different mining methods, it can be divided into two types: lattice type and overflow type.
Working principle of ball mill
The ball mill is composed of a horizontal cylinder, a hollow shaft for feeding and discharging, and a grinding head. The cylinder is a long cylinder. The cylinder is provided with an abrasive body. The cylinder is made of steel plate, and the steel liner is fixed with the cylinder. The grinding body Generally, it is a steel ball, and is loaded into the cylinder according to different diameters and a certain proportion, and the grinding body can also be used as a steel section.
According to the particle size of the grinding material, the material is loaded into the cylinder body by the hollow shaft of the ball mill feeding end. When the ball mill cylinder rotates, the grinding body acts due to inertia and centrifugal force, and the friction force acts to make it close to the cylinder liner. The cylinder is carried away. When it is brought to a certain height, it is thrown off due to its own gravity. The falling abrasive body crushes the material in the cylinder like a projectile.
The material is uniformly fed into the mill bin by the feeding device through the hollow shaft of the feeding material. The bin has a step liner or a corrugated liner, and various steel balls are loaded therein. The cylinder rotates to generate centrifugal force to bring the steel ball to a certain height. Drops, causing heavy impact and grinding on the material. After the material reaches the coarse grinding, the material enters the second chamber through the single-layer compartment board. The warehouse is provided with a flat lining plate with steel balls inside to further grind the material. The powder is discharged through the discharge raft to complete the grinding operation.
During the process of turning the cylinder, the grinding body also has a sliding phenomenon. In the process of sliding, the material is grounded. In order to effectively use the grinding effect, when the general grain size of the material is large, the grinding body is used. Separated into two sections by the compartment board, which becomes a double warehouse. When the material enters the warehouse, it is crushed by the steel ball. When the material enters the second warehouse, the steel section grinds the material, and the finely-qualified material is discharged from the hollow shaft of the discharge end. When grinding small materials with small particles, such as sand No. 2 slag, coarse fly ash, the mill barrel can be without a partition, which becomes a single-cylinder barrel mill, and the grinding body can also use steel sections.
The raw material is ground into a hollow cylinder through a hollow journal, and the cylinder is filled with grinding media of various diameters (steel balls, steel bars or gravels, etc.). When the cylinder rotates around the horizontal axis at a certain rotation speed, the medium and the raw materials contained in the cylinder are separated from the cylinder by the centrifugal force and the friction force, and when the gravity reaches the certain height, the gravity is greater than the centrifugal force. The body wall is thrown down or rolled down, crushing the ore due to impact. At the same time, during the rotation of the mill, the sliding movement of the grinding media to each other also produces a grinding effect on the raw materials. The ground material is discharged through a hollow journal.
Performance characteristics of ball mill
1. increase the effective volume
Increasing the effective volume of the mill can increase the mill productivity, the thickness of the liner, the weight, increase the power consumption, reduce the effective volume of the cylinder, and reduce the production efficiency of the ball mill. If the magnetic lining plate is selected, the effective volume of the cylinder can be increased, and the weight is relatively reduced, and the power consumption is reduced. However, the use of a thinner magnetic liner also has certain drawbacks. Because of its small thickness, the impact resistance is not as good as the current Cr-Mn-Mo alloy cast steel liner, which is prone to cracking. For example, some manufacturers use grooved annular lining for the lining problem, which increases the contact surface of the ball ore, enhances the grinding effect, and has the ability to lift the ore, reduce energy consumption, and is widely used.
2. increase the filling rate and transfer rate
The processing capacity of the ball mill increases with the increase of the filling rate of the steel ball. Increasing the filling rate increases the probability of grinding the ore and the self-grinding effect of the ore. When the ball filling rate is 45%, the ball mill load is large, and when it exceeds 45%, the load is greatly reduced as the filling rate increases. This is mainly because as the filling rate increases, the ball throwing point is raised, and the combined action point of the falling of the steel ball accelerates toward and closes to the center of rotation, and the resultant moment is greatly shortened to become a negative value. The load required for the impact torque of the steel ball (mineral) falls from large to zero until it becomes the power to push the cylinder to rotate (that is, the resultant force exceeds the center, and the combined torque is negative).
3. Changing the shape of the grinding medium
The elliptical ball medium can be used instead of the existing ball medium. The advantages of the elliptical ball compared with the ball are as follows:
a. Compared with the ball of the same diameter, the elliptical ball has a weight increase of 62%, and the impact force is strong, which improves the crushing ability;
b. The point contact between the elliptical balls is replaced by the line contact instead of the ball, the contact area is 4 times larger than the sphere, the material has selective pulverization and good sieving effect, the product granularity is uniform, and the over-grinding phenomenon is reduced;
c. Compared with the ball of the same diameter, the surface area of the ball is increased by 8%, which increases the contact surface between the steel ball medium and the material, and improves the grinding ability;
d. The elliptical ball and the mill lining plate replace the point contact of the ball with line contact, reduce the wear of the steel ball medium on the lining plate, reduce the impact of the steel ball medium and the mill lining plate, thereby reducing the steel ball medium. And wear of the mill liner to extend the service life;
e. The ellipsoid also has antistatic and anti-moist effects, which can reduce the adsorption of fine powder and reduce the phenomenon of full grinding.
Compared with the spherical body, the ellipsoidal ball can greatly improve the crushing and grinding ability of the ball mill, and at the same time reduce the equipment loss accordingly.
Technical Parameters of ball mill
|
Product specifications
(m)
|
Production capacity
(t/h)
|
Mill
form
|
transmission
form
|
power
(kw)
|
Reducer
|
weight
(t)
|
Remarks
|
|
model
|
Speed ratio
|
|
Φ2.2×7m
|
12-13
|
Loop
|
edge
|
380
|
ZD70
|
5
|
54
|
|
|
Φ2.4×7m
|
15-17
|
Loop
|
edge
|
475
|
JR75
|
-
74
|
-
5
|
|
|
Φ2.4×8m
|
16-18
|
Loop
|
edge
|
475
|
JR75
|
-
74
|
-
5
|
|
|
Φ3×9m
|
42-47
|
Loop
|
edge
|
1000
|
MBY800
|
-
1
|
-
5
|
Motor free
|
|
Φ3.2×9m
|
62-65
|
Loop
|
edge
|
1250
|
MBY900
|
-
1
|
-
5
|
Motor free
|
|
Φ3.8×7.5m
|
80
|
Loop
|
edge
|
1600
|
JDX900
|
-
6
|
233
|
|
|
Φ4.6×10+3.5m
|
190
|
Loop
|
center
|
3550
|
JQS3550
|
-
1
|
358
|
|
|
Φ4.6×10.5+3.5m
|
210
|
Loop
|
center
|
3550
|
JQS3550
|
-
1
|
360
|
|
