Structural design of rubber lining board for ball mill

18-06-2019

Authors:Kosga Sales Director Johnny Ren


After introducing the application of Kosga 3.6x4m rubber bushing for ball mill, many mining companies and letters inquired about the structural design of rubber bushing for ball mill. In exchange for experience, Kosga introduces the following.


During the operation of the mill, the impact kinetic energy generated by the material falling in the cylinder varies with the height of the material. If the material slides along the tube liner, it accelerates liner wear. The section shape of cylinder rubber liner is similar to that of steel liner, but it wears out too fast. Through practice, the rubber liner structure composed of flat liner and lifting rod can minimize sliding.

Ball mill rubber lining

Kosga company introduced according to the actual operation data: when the impact angle of the ball is between 0-90° the bigger the impact angle is, the smaller the sliding friction is. It is according to this dominant idea that we correctly select the shape and size of the cross section of rubber liner and strip.


Shell rubber bushing lifting rod, also known as cylindrical lifting bushing plate, can be divided into symmetric lifting and asymmetric lifting two types. According to its section shape can be divided into K, D, S, F and so on. It adopts asymmetric k-shaped strip, which is the basic structure of rubber lifting rod of circular shell of wet mill.Kosga also found in the industrial test that the natural cross-section shape of rubber lifting rod wear is mostly K-shaped. The non-lifting surface of K-type lifting rod is vertical, and the lifting surface is composed of straight line and arc. Practice has proved that although the asymmetric K-type lifting rod can not be used reversely compared with the symmetrical lifting rod, its service life is higher.


It is very important to choose the height and size of lifter bars, which will directly affect the grinding efficiency and the lifetime of lifter bars. The lifter bars designed by us are 50 mm higher than the lining plate, and the angle between the arc of lifter bars lifting surface and the radius of mill is 60 degrees, so that a more advantageous impact angle of falling sphere can be obtained. The non-lifting surface of lifter bars is kept perpendicular and has a small rounded angle of R5, which prevents the abrasive body from moving disorderly after falling. The impact in the opposite direction.


It is also very important to choose the ratio of lifter bars height to spacing reasonably. If the distance between lifter bars is too large, it will form a large space, and the ball material will easily slide. If the distance between lifter bars is too small, the material will fill it and form a plane, which will easily lead to worsening of the top of lifter bars, and reduce the grinding efficiency. Kosga summarizes an empirical formula:

SAG mill rubber liners

The formula only considers the influence of mill speed, but does not consider the influence of mill diameter, mill medium and feed size, so we only use it for reference in design.


According to Kosga's operation, when the speed is 75%, the influence of A/B ratio on productivity and power consumption

FGD mill rubber liners

When A/B-3-5, the mill has higher production capacity and lower power consumption. According to the specific conditions of the mill, the ratio of A/B is 4.6.


The cross section shape of shell rubber liner adopts rectangular flat liner widely used in the world. Flat lining plate should not be too thick, too thick will not only make lifter bars scrap too much, but also reduce the effective capacity of the mill. We choose the liner thickness of 80mm, so that lifter bars protrusion liner height of 50mm.


Rubber lining, lifter bars and mill shell connection mode, using the world's current universal flexible connection Insert T-shaped pressing plate into lifter bars without direct contact with ball material


Firm and reliable connection, good sealing, long service life, and because there is a gap between T-type pressure plate and T-type groove of lifter bars, the force acting on the surface of lifter bars is reduced, thus achieving the purpose of reducing wear. Using this connection method, the service life can be increased by more than 30%.


The structure design of the rubber liner is selected according to the specific working conditions of the kosga ball mill and international experience. The thickness and width of rubber liner and the height, spacing and cross-section shape of the strip are selected and designed carefully according to the diameter, speed, medium diameter and feed size of the mill operated by Kosga.



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