Method of Reducing Wear Rate of Ball Mill Steel Ball

In the process of grinding and beneficiation, the consumption of ball mill steel ball is very large, which is the largest consumable of ball mill users. In order to make up for the loss of ball used by ball mill and ensure the invariability of ball load particle size in ball mill, ball mill users need to add steel ball regularly according to a certain proportion.

The consumption of ball mill steel ball mainly includes mechanical wear and corrosion wear. They are irreversible processes of "physical mechanical" and "physical chemical". On the premise of ensuring the normal operation of ball mill equipment, how to effectively reduce the wear consumption of ball mill steel ball is a subject that many ball mill users and ball mill steel ball manufacturers like me have been studying. Through repeated demonstration, it is found that the wear of ball mill steel ball can be reduced mainly through the following ways:

In the process of grinding and beneficiation, the steel ball of the ball mill consumes a lot and is the largest consumable of the ball mill user. In order to make up for the loss of the steel ball used by the ball mill and ensure the constant load particle size of the steel ball in the ball mill, the ball mill user needs to add the steel ball regularly according to a certain proportion.

1. Change grindability of ore

The particle size of the material fed into the ball mill is one of the reasons affecting the wear of the ball mill steel ball. Generally, if the grindability of the feed particle size is small, the ore is easy to grind, the wear of the ball mill steel ball is smaller, and the energy consumption is also smaller; On the contrary, it is the opposite.

In the actual production process, if the ore is difficult to grind or the ore requires fine grinding, it can be considered to appropriately add certain chemical beneficiation agents in the grinding process to improve the grinding effect and increase the grinding efficiency when the economic and site conditions permit; Or heat the ore to change the mechanical properties of the whole ore and reduce the hardness of the ore. These two methods can effectively reduce the wear of ball mill steel ball, and then improve the production efficiency of ball mill.

2. Reduce the particle size of feed into the mill

The larger the grinding particle size of the ball mill, the greater the work of the ball mill on the ore material. In order to achieve the specified grinding and discharging fineness, the workload of the ball mill is bound to increase, and then the wear of the steel ball will also increase.

In order to reduce the wear of the ball mill, it can be solved by reducing the feed particle size of the grinding. Therefore, it is necessary to reduce the particle size of the crushed ore products, that is, "more crushing and less grinding".

3. Reasonable steel ball filling rate

When the rotation speed of the ball mill reaches a certain degree, the filling rate is large, the more times the grinding medium steel ball strikes the ore materials, the larger the grinding lifting area and the faster the wear. In addition, the high filling rate will also change the motion and operation track state of the ball mill steel ball in the ball mill, reducing the striking effect of the steel ball on large particle ore materials. On the contrary, the filling rate is too small and the grinding effect is weak.

At present, the filling rate of steel balls in the grinding and beneficiation operation of concentrator is generally 45% ~ 50%, which is actually too high. According to the actual situation of each concentrator, it is not a reasonable filling rate. Therefore, it is necessary to determine the reasonable ball loading through beneficiation test.

If the filling rate is too high, it is equivalent to a person eating too much, which is easy to produce the phenomenon of "bloating", and the stomach can not operate normally, that is, indigestion. The internal food can not achieve the most efficient grinding and digestion, and the utilization rate is reduced, which will inevitably lead to high wear and waste.

4. Reasonable steel ball ratio, steel ball grading, size and quality of ball mill

Because the steel ball in the ball mill is in point contact with the material, if the diameter of the steel ball in the ball mill is too large, the throwing impact breaking force is also large, the wear is too fast, and it is easy to cause the material to break along the direction of penetration force, which is also an important reason for the breaking of the steel ball in the ball mill, which affects the grinding efficiency. In addition, with the same ball filling rate, if the ball diameter of the ball mill is too large, the number (number) of steel balls will be small. Although the weight of a single steel ball is large and the impact crushing capacity is large, because the gap between the ball mills is too large, individual ores will be crushed and pulverized, and some ores will not be impacted and crushed but the particles are too large, that is, the particle size of the products is uneven; The steel ball diameter of the ball mill is too small, because the weight of a single steel ball is small, the crushing force on the ore is small, but the grinding force between the steel ball, ore and steel ball is large (provided that the ore can be ground, and it is not easy to grind if the particle is too large), which will cause that individual ores are not broken enough and it is not easy to grind, and the grinding efficiency of another part of ores will be reduced. Therefore, a reasonable steel ball size ratio will not only reduce the wear of ball mill steel ball, but also effectively improve the grinding efficiency. The quality of ball mill steel ball is divided into 369 grades and various types. As for what kind of working condition is suitable for what kind of steel ball, it is also a very important topic for us to study. Generally speaking, there is no exactly same two leaves in a radish pit. Specific problems need to be analyzed. Is the more expensive ball mill steel ball the better? On the premise of not asking too much, the more expensive the steel ball, the better the natural quality. However, this quality refers to the high and uniform hardness distribution from the surface of the unused steel ball to the heart of the finished product. However, the physical and chemical changes of the ball mill steel ball during use are not considered according to the working conditions of the ball mill. Therefore, a reasonable ball mill steel ball scheme can be worked out only by investigating the working conditions of the ball mill, Only in this way can we make the best use of ball mill steel balls, and then reduce wear and production costs.

5. Reasonable grinding concentrationThe grinding concentration will affect the specific gravity of the pulp, the adhesion of the material around the steel ball and the flow capacity of the pulp. If the grinding concentration is high, the adhesion of the material around the steel ball is good, the impact and grinding effect of the steel ball on the material is also large, and the wear of the steel ball is faster. In actual production, the grinding concentration can be controlled by controlling the ore feeding amount, or make-up water amount, or adjusting the classification function. Too low grinding concentration is not good, which will lead to small material impact and grinding effect, and the grinding efficiency will also be reduced.

6. Control the speed of ball mill

On the premise that the steel ball ratio of the ball mill is reasonable, with the increase of the speed of the ball mill, the steel ball of the ball mill inside the cylinder will change from the discharge state to the throwing state. When the speed rate increases to a certain extent, the useful power reaches the maximum value. At this time, the grinding effect is the best and the wear of the steel ball of the ball mill is the most reasonable. The theoretical critical speed rate of ball mill is generally 78 ~ 84%. Due to material properties and other factors, the speed of the ball mill shall be determined according to the actual working condition of the ball mill. The high speed of the ball mill will increase the impact force of the steel ball and throw it too high. Just like throwing the shot put too far, the steel ball will not hit the ore and will be in direct contact with the lining plate. Moreover, the impact force will also increase. The particles will be too large because the ore is not broken, or a small amount of ore will be pulverized if broken by the steel ball. The excessive direct contact and impact force between the steel ball and the lining plate will lead to the crushing of the steel ball and the lining plate, resulting in wear and increased cost. If the rotation speed of the ball mill is too low, the steel ball will only be ground without crushing, and the ore will not get enough crushing force, that is, the particle size is too large, and the steel ball will not be effectively utilized, which will eventually lead to unqualified discharge fineness.

In the grinding process, there are many factors affecting the wear of ball mill steel ball, and the variables are also large, and most of them are difficult to analyze. They can only be analyzed and judged according to experience and as many data as possible. In order to reduce the wear of ball mill steel ball on the premise of ensuring the qualified quality index of finished products, we must consider multiple links in order to achieve the final technical and economic index and good product quality index.