Ball mill operation tipsDate: 2019-07-02 Views:
Ball mills are a very common grinding equipment only in mineral processing applications. The principle of grinding is to use the friction between the material and the steel ball or steel column and the rotating form of the drum to promote the material to the ideal grain size standard. This standard is used to facilitate the classification and flotation in the subsequent beneficiation process. Then, the grinding equipment is very important in the ore dressing equipment. The ball mill bears the heavy responsibility of grinding. If there is a slight error, the consequences will be great. Therefore, whether the ball mill grinding operation as the central link has to be emphasized How about the method? Here, Zhongnuo Machinery believes that as long as you master the secrets of “all ore, large returning sand, high concentration”, you can achieve the most ideal grinding effect. This will be described in detail below.
What is “all mines”?In fact, we can understand this way, we must also pay attention to the situation is "all give mine." Why do you want to say this? In fact, there are two main implications here: one is that the ore size is uniform; the other is that the ore rate (the amount of grinders fed into the mill per unit time) is constant. In order to improve the grinding efficiency, the ore supply should be continuous, uniform and stable at a high level. For a long time, the mass fraction in the mill will fluctuate frequently, which is not conducive to the grinding process. Grinding feedstock tends to have particle size segregation in the silo - the middle is fine, and the surrounding coarse is easy to cause uneven composition of the feed. If it can not be adjusted according to the particle size, the "flatness" will appear. Therefore, the silo should be used as much as possible to feed the mine.
Then the meaning of “large sand returning” is also very simple.We require “big sand return” in the operation of the small ball mill grid plate. In order to explain such benefits, first we will first talk about what is sand return. Sand return refers to the coarse-grained grade that is returned to the grinding machine by the classifier when it is closed. The amount of returning minerals is often several times that of the original ore. The ratio of the amount of sand returned to the amount of ore delivered is called the return sand ratio. Practice has proved that the size of the sand return ratio will directly affect the productivity of the mill. The larger returning sand ratio increases the grouting speed of the grinder due to the increase of the total ore supply of the grinder, and the residence time of the material in the grinder is shortened and the cycle is accelerated. In addition, although the sand returning is a coarse ore, it is finer than the original ore. Therefore, the grain size composition of the mill is fine, and the comprehensive result is beneficial to increase the productivity of the small ball mill. By studying the relationship between the return sand ratio and the relative productivity of the mill. It can be known that within a certain range (such as between 100% and 500%), with the increase of the sand-return ratio, the productivity of the mill increases with a certain value, the productivity increase is small, and the mill is fully fed. Through the ability, it is easy to cause the ball to swell. Therefore, the sand return ratio should be kept stable and close to a constant value.
The so-called “high concentration”, the grinding mass fraction is an important factor affecting the productivity of the mill.It determines the friction between the grinding media and the material to be ground, the fluidity of the slurry and the effective density of the medium (the difference between the medium and the pulp density). ). At the same time, the amount of ore per unit volume in the ore discharge is large, so the amount of ore discharged is large. However, the mass fraction of the pulp is too high. Due to the increase of the pulp density, the effective density and activity of the dry ball mill ball will be weakened, the mass fraction will be high, the viscosity will be high, the fluidity will be deteriorated, and the total discharge capacity will be reduced. On the contrary, it will lead to a decrease in the productivity of the mill, and even a tendency to "bloat". Mainly refers to the mass fraction (pulp mass fraction) is the percentage of ore quality (dry weight) and pulp quality (ore + water) in the pulp, where the mass fraction refers to the pulp mass fraction (grinding mass fraction) in the grinding machine. In the operation of the mill, a higher grinding mass fraction is generally used, so that a layer of pulp can be attached to the surface of the medium to enhance the abrasive effect on the grinding. Therefore, "high concentration" means that the grinding quality fraction is appropriately increased within a certain range, which is advantageous for improving the grinding effect.
As long as you master the above-mentioned ball mill operating specifications, or learn from the experience of the predecessors, you can let the ball mill work under the best working conditions. The core issue exposed by the nine-character secret is the balance between input and output efficiency.