The ball mill liner has 3 functions, 8 classifications and 10 installation requirements

The inner surface of the ball mill cylinder is generally equipped with lining plates of various shapes. Liner is the main wearing parts of the ball mill, its use cost is about 2%-3% of the product price, and the performance and service life of the liner is a matter of great concern to users. The performance of liner will directly affect the performance of ball mill. This paper introduces 3 functions, 8 categories and 10 installation requirements of ball mill liner.

The materials used to manufacture lining boards are metal materials (manganese steel, chromium steel, etc.) and rubber. At present, the metal material liner is used more in China, and the rubber liner is also used in the mine.

Lining board mainly has the following functions:

1, protect the cylinder and enhance the rigidity of the cylinder is an important part of the ball mill, and the price is more expensive, after the lining plate is installed in the cylinder body, the cylinder will not directly bear the impact and grinding of the grinding medium and the grinding material, thus protecting the cylinder and extending the service life of the cylinder and the entire equipment. The lining plate and the cylinder are closely combined together, which also plays a role in enhancing the stiffness of the cylinder.

2, transfer energy in the cylinder rotation process, with the help of the special shape and friction of the liner surface, the ball is raised to a certain height, giving it a certain potential energy and throwing kinetic energy, so that they produce in line with the requirements of the grinding process of the "arc and parabola" movement trajectory, impact and grinding materials.

3, automatic grading ball automatic grading lining plate such as Angle spiral lining plate, cone grading lining plate, etc., can make the grinding body of different levels in the cylinder, along the mill axis, according to the change of grinding particle size reasonable forward grading, so that a variety of different diameter grinding body in the process of crushing the corresponding particle size material, play the maximum function. In other words, the automatic grading liner enables the larger steel balls in the same milling bin to be assembled at the feed end of the bin to crush the larger block, while the smaller steel balls are assembled at the discharge end of the bin to crush the smaller block.

The shape of the ball mill liner is divided into 9 shapes according to different needs, which are wedge, waveform, flat convex, flat, stepped, strip, rudder shape, K-shaped rubber liner and B-shaped rubber liner (as shown in the following figure).
① The flat lining plate is used for fine grinding bin, and the height of the grinding body depends on the coefficient of static friction between the tree and the plate.
② The laminate liner used in the first bin can make the grinding body rise higher and have greater impact energy.
The convex lining plate is similar to the laminate lining plate.
④ Corrugated liner is suitable for baseball grinding.
⑤ The stepped lining plate is suitable for crushing silo, which is widely used. It has the following three advantages:
a) The lifting height of the same ball layer is uniform.
b) Wear the surface of the plate evenly.
c) The restraining ability of the liner acts on the other layers of the abrasive body, reducing the sliding wear between the liner and the outermost abrasive body, and also preventing the sliding and wear between the different layers of the abrasive body.
⑥ Hemispherical liner, suitable for crushing silo.
7 Waveform liner, suitable for fine grinding silo laying bolt-free liner, its crest and pinch are very small.
⑧ Grading liner, can make the steel ball automatically grading. The shape of cylinder liner has great influence on the work of ball mill. When dealing with coarse materials, the ball mill cylinder should be undulating (such as waveform, convex, lap shape and stage shape) lining plate.

This shape liner has the ability to lift the grinding medium to a higher height, thereby enhancing the impact capacity of the medium and improving the production capacity of the ball mill. It is often used for first stage grinding. Fine grinding (often refers to the second stage grinding) is mainly by grinding and stripping.
The smooth lining plate is easy to slide and roll the steel ball, and the grinding and stripping effect is strong, so the smooth lining plate is used in the fine grinding ball mill barrel. The gap between the end liner and the end cover of the cylinder must be filled with cement mortar with a compressive strength of 43.5MPa.
The bolt fixing the end liner shall not allow the cement mortar to fill, and shall be able to turn or enter and exit. The liner is generally directional, and attention must be paid to the installation, not to install the reverse.
The arc length of all annular gaps shall not exceed 310mm, and the excess places shall be wedged into with steel plates to partition them. The gap between adjacent lining plates is not greater than 3~9mm.

A partition layer should be laid between the liner and the surface of the cylinder body according to the design requirements. If there is no requirement, cement mortar with compressive strength of 42.5MPa can be filled between them as much as possible. The excess part can be squeezed out through the solid liner bolt, and the liner bolt is tightened again after the cement mortar solidified.
When installing the lining plate with the rubber backing plate, the rolled rubber plate should be opened 3 to 4 weeks before installation to make it freely extend; When using the rubber sheet, the long side of the rubber sheet should follow the axis of the cylinder, and the short side should follow the circumference of the cylinder.
Carefully check the geometry of the liner bolt holes and liner bolts, and carefully clean the flash, burr, and protrudation on the liner bolt holes and liner bolts, so that the bolts can be freely inserted into the required position. The complete set of liner bolts shall consist of dazzling bolts, dust washers, flat washers, spring washers and nuts. In order to prevent dust leakage, do not forget to use dust cushion when using. Use a torque wrench to tighten liner bolts. Tighten liner bolts of different specifications according to the corresponding tightening torque requirements.