The ball mill is the main equipment of the ore dressing plant and also accounts for a considerable proportion of the investment in the construction of the ore dressing plant. Therefore, it is very important to ensure the grinding efficiency and service life of the ball mill. Among them, the ball mill liner, as an important part of the ball mill, can not only effectively protect the ball mill cylinder, but also enhance the impact and grinding between the medium and the material to improve the grinding efficiency.
Under the long-term action of grinding media, the liner of the ball mill generally wears out too quickly. So the question is, what are the reasons for the rapid wear of the liner of the ball mill? How should it be dealt with or improved
1. Mutual wear between ball mill liner and steel ball
The ball mill liner and steel balls are both vulnerable parts. During the grinding process, the ball mill steel balls and materials make parabolic falling motion in the cylinder. At this time, the ball mill liner, steel balls and materials will collide with each other and produce friction. In continuous operation, the ball mill liner and steel balls will be seriously worn, which is directly related to the hardness of the material. The harder the material, the faster the wear rate of the ball mill liner and steel balls. In severe cases, it may cause equipment damage or even safety accidents. In addition, the wear of the ball mill liner is also related to the steel balls. The size and number of steel balls will affect the service life of the ball mill liner. During the operation of the ball mill, if the amount of steel balls or larger diameter steel balls are increased, the wear of the ball mill liner will be aggravated.
How to deal with it:
Reasonable selection of ball mill liner and steel ball is one of the main ways to reduce the wear rate of liner.
a. Relevant staff need to understand the ratio of ball mill liner to steel ball, and select the corresponding steel ball size and quantity according to the ratio. Under normal circumstances, the hardness ratio of conventional ball mill liner to steel ball is about 1:0.8.
b. Control the ratio of material to steel ball. The material is twice as much as the steel ball.
c. When selecting a ball mill, you should choose a suitable ball mill liner according to the type of mineral, control the hardness of the ball mill liner and steel ball, and make a reasonable match between the steel ball and liner.
2. The material of ball mill lining is unreasonable
The material of the ball mill liner and its heat treatment process are the key to determining the mechanical properties of the ball mill liner. If the liner material is not selected properly, its fatigue strength and life will be greatly reduced. Not only will it fail to meet the working requirements of the ball mill, it may even cause plastic deformation or bulging.
How to deal with it:
Choose new wear-resistant lining materials. Currently, the commonly used ball mill lining materials include high manganese steel, high chromium steel, alloy steel and wear-resistant rubber. Among them, wear-resistant rubber is a new lining material that has emerged in the past decade. The composite lining composed of wear-resistant rubber and alloy steel not only improves the toughness of the lining, but also solves the contradiction between its toughness and rigidity.
3. The heat treatment process of ball mill liner is unreasonable
Improper heat treatment of the ball mill liner will not only increase the wear of the liner, but also affect the yield strength of the liner, causing the fixing bolts of the ball mill liner to break under a large shear force.
In actual operation, if the staff lacks knowledge of the liner material and the heat treatment of the ball mill liner is unreasonable, it is easy to cause the strengthening effect of the ball mill liner to be inadequate, and deformation often occurs when it is hit by steel balls and materials.
How to deal with it:
Preheating the ball mill liner can effectively reduce the wear of the ball mill liner. The appropriate preheating process can be selected according to the liner material.
4. The ball mill is not operating normally
When the ball mill is in an abnormal operating state, it will also have an adverse effect on the lining of the ball mill. When the ball mill is in normal operation, the steel balls are mixed with the materials. When the steel balls are thrown onto the lining, they form a barrier with the materials, playing a buffering role while gradually grinding the materials. If the ball mill is in low load operation, the steel balls will directly impact the lining, causing serious wear and even breakage of the lining.
How to deal with it:
Relevant staff need to make timely adjustments according to the operating status of the ball mill. When the ball mill is running under low load, the ore input of the ball mill needs to be adjusted in time to ensure the grindability of the material.
In addition to the four reasons for wear described above, the design, manufacture and installation of the ball mill liner may also cause the ball mill liner to wear too quickly. In order to improve the efficiency of the ball mill liner, it is necessary to analyze the reasons for liner wear in order to develop a reasonable solution.
