Misunderstandings in Judging the Quality of Ball Mill Steel Balls and Its Influence

The quality of the steel balls of the ball mill affects both the productivity and the consumption of the balls, which in turn affects the cost of the grinding media. It is wrong to simply pursue high hardness and low unit consumption. High hardness and low unit consumption do not mean low cost. Balls with high hardness and low unit consumption are often expensive. High hardness does not necessarily increase productivity, or even decrease it. Only high productivity can reduce the unit consumption indicators. Therefore, the primary criteria for selecting steel balls should be high mill productivity and low grinding media cost. Only high productivity and low grinding media cost can have good economic benefits. Economic efficiency is a necessary condition for the survival and development of an enterprise.

When choosing a steel ball, two issues are often overlooked: the harder the steel ball is, the better it is, but the appropriate hardness value; the density of the steel ball is also an issue that cannot be ignored. Regarding the impact of hardness, generally speaking, as the hardness increases, as long as no crushing occurs, the unit consumption of the steel ball decreases; and the deformation of the ball is small, and the deformation of the ball is small during the crushing, and the energy can be used to crush the ore particles. The productivity of the mill can be increased. But the increase in the hardness of the steel ball can only be moderate, there is an appropriate range, not the harder the better. If only the ball consumption is considered, the higher the hardness, the lower the consumption. But for the mill productivity, within a certain range, the productivity increases with the increase of the hardness of the steel ball, but when the hardness exceeds a certain range, it will have an adverse effect on the mill productivity and reduce the mill productivity. There are two unfavorable reasons for grinding when the hardness of the steel ball is too high:

    ① The rebound of the steel ball is serious, causing part of the energy loss in the rebound, so the energy of the steel ball is not used more for crushing, so it affects the crushing;

    ② When the hardness of the steel ball is too high, the ball will slide severely when in contact with each other, and the ore particles between the balls cannot be effectively gnawed, and the grinding effect of the ore particles is weakened.

    Regarding the influence of steel ball density on ore grinding, generally speaking, balls of the same size have a higher density and a higher productivity, while a smaller density has a lower productivity.

    The density of steel balls is affected by three factors:

    ①The influence of material, steel, cast iron, alloy steel, etc., the density of different materials is different, the density of steel is greater than that of cast iron, and the density of alloy steel varies according to the density and content of the main alloying elements.

    ②The influence of steel ball manufacturing method. Rolled and forged steel balls have dense structure, so the density is high. The structure of cast steel balls, cast iron balls or cast alloy balls is not very dense, and even has pores in them, so the density Smaller.

    ③The influence of the metallographic structure of the steel ball, the density under different crystal structures such as martensite, austenite, bainite, ferrite, etc. is also different, which also affects the crystallinity.