To find out the cause of the stress on the ball mill liner, we need to understand the ball mill liner. Here I will tell you about the types of ball mill liners and the functions of the ball mill barrel liner.

Ball mill liners are mainly divided into: flat liner, pressure strip liner, convex rib liner, corrugated liner, step liner, hemispherical liner, small corrugated liner, graded liner, end cover liner.

The main function of the ball mill barrel liner is to use the liner surface and convex peaks to bring up steel balls to crush and grind the materials.

The cause of the stress on the ball mill liner:

When the grinding media group and the material are in motion, the large-diameter steel balls are mainly distributed in the outer circle. Most of them fall on the bottom of the material bed when they fall, and a small part falls on the liner. Due to the buffering effect of the material and the collision between the material and the steel ball during work, the movement trajectory of the steel ball is disrupted, causing the impact point to deviate and the height to decrease, so the impact stress of the steel ball on the liner can be reduced. Therefore, in general, the falling steel balls and materials do not directly impact the lining of the cylinder, but impact the steel balls and material layer.

Through a lot of analysis, it is confirmed that most steel balls hit the lining after several collisions, so the impact on the lining is much smaller than the impact energy generated by the vertical falling object within the effective diameter. The main force of the steel ball impacting the lining and causing the lining to break is the vertical component of the tangent between the lining surface and the contact point of the steel ball. The magnitude of this force is affected by many factors such as the shape of the lining surface, the motion state, speed and direction of the steel ball, which also greatly weakens the intensity of the direct force and reduces the impact of the lining.

Since the impact time of the lining is extremely short and difficult to measure, it can be explained by the impact energy received. For the convenience of calculation, the following assumptions are made: the gravitational potential energy of the steel ball after being lifted is completely converted into the impact energy of the lining; the lining is 314mm long, 250m wide and 40mm thick, and the number of balls falling at the same time in the axial direction is 4. The diameter of the steel ball is 100mm; the specific calculation formula is not mentioned here.

From the above, we can see that the impact load per unit area of the liner is proportional to the diameter of the ball mill and the number of steel balls that can be simultaneously discharged on the axial direction of the liner, and inversely proportional to the thickness of the liner. When the diameter of the ball mill increases, the speed increases, and the weight of the steel ball increases, the impact force on the liner also increases. Therefore, appropriately increasing the thickness of the liner will not have a significant effect on the effective diameter of the ball mill, but it is very effective in reducing the impact energy.

However, in the actual process, when the steel ball falls, it will be impacted by the surrounding steel balls and buffered by the material. Therefore, the actual impact energy received by the liner is somewhat different from the theoretical calculation result, and the theoretical result is much larger than the actual value.