Time: 2022-03-12

Ball mills are a very common type of grinding equipment only in beneficiation applications. The grinding principle is to use the friction between the material and the steel ball or steel column and the drum rotation way to promote the material to reach the ideal particle size standard. This standard is used to facilitate operations of classification and flotation in the process of subsequent benefit. Then the very important grinding equipment in the beneficiation equipment, the ball mill bears the great responsibility of grinding. If there is a small mistake, the consequences will be great, so the core link of the ball mill grinding operation Balls, is there any operation to emphasize? method? Shanghai Joyal tells you that as long as you master the nine-character secret of “uniform ore feeding, large sand return and high concentration”, you can achieve the most ideal grinding effect.
What is “everything to me”? In fact, we can understand it like this, and we should also pay attention to the “all supply to the mine” situation. Why do you say that? In fact, there are two main meanings here: one is that the ore feed particle size is uniform; In order to improve grinding efficiency, the amount of ore to be fed must be continuous, uniform and stable at a high level. More time and less time will cause the mass fraction in the grinding machine to fluctuate frequently, which is not conducive to the grinding process. Grinding raw materials tend to have particle size segregation in the silo: fine in the middle and coarse in the surrounding area, which can easily cause uneven raw material composition. Therefore, the silo must try to use multi-point discharge to feed the ore.
So the meaning of “big sand return” is also very simple. We require that the “big sand return” be done during the operation of the small ball mill grate plate. To explain such benefits, let’s first talk about what sand return is. Sand return refers to the grade of coarse grain returned by the classifier to the crushing machine for re-crushing during closed circuit crushing. The amount of ore returned is usually several times the original amount of ore supplied. The ratio of the amount of sand returned to the amount of raw ore feed is called the sand return ratio. Practice has shown that the size of the sand return ratio will directly affect the productivity of the mill. The higher sand return ratio increases the total ore feed volume of the mill, thus increasing the discharge rate of the mill, shortening the residence time of the materials in the mill and speeding up the cycle. In addition, although the returned sand is a coarse-grained ore, it is finer than the original ore after all, so the particle size composition of the entire mill feed becomes finer and the overall result is beneficial. to improve mill productivity. small ball mill Studying the relationship between the sand return rate and the relative productivity of the mill. It can be known that within a certain range (such as between 100% and 500%) as the sand return ratio increases, the productivity of the mill increases with it, when it reaches a certain value, the productivity increase is very small, and the full feed of the mill is close to the maximum. Through the skill, it is easy to make the ball distend through the belly. Therefore, the sand return ratio must be kept stable, close to a constant value.
The so-called “high concentration”, the grinding mass fraction is an important factor affecting the productivity of the mill, which determines the friction between the grinding medium and the material to be ground, the fluidity of the pulp and the effective density of the medium (the difference between the density of the medium and the pulp is different). 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, if the pulp mass fraction is too high, due to the increase in pulp density, the effective density and mobility of the grinding medium and the impact effect will be weakened by the loss of the steel balls from the grinding medium. dry ball mill on the contrary, it will reduce the productivity of the grinding machine and even be prone to “swelling”. It mainly refers to the mass fraction (pulp mass fraction), which is the percentage of ore mass (dry weight) and pulp mass (ore + ag