How to Select the Appropriate Steel Balls for Your Ball Mill?

The grinding effect of ball mill depends on the friction between grinding balls and materials to reach the grinding purpose, so the quality of steel ball has the very significant impact on the ball mill production efficiency, the energy consumption of ball mill and ore grinding quality, even the cost of grinding medium. Therefore, selecting the appropriate grinding balls is very important, then how to select them, FTM will explain this for the ball mill users in the following words.

When choosing the steel balls, two problems are often overlooked: The steel ball is not the harder the better, but has a proper hardness value; The density of steel ball is also an important issue.

It’s wrong to purely pursuit the high hardness and low unit-consumption. High hardness and low unit-consumption do not equal the low cost, because the high hardness and low unit-consumption grinding balls price tends to be very high. And the high hardness does not necessarily lead to the productivity increased, or even decline, only the high productivity can reduce the specific unit consumption index. Therefore, the primary standard for choosing steel balls is to have the high-productivity of ball mill and the low-cost of ore grinding medium.

About the influence of steel ball hardness, generally speaking, with the increase of hardness, as long as the steel ball isn’t broken, the unit consumption of steel ball will decline, at the same time the steel ball has the little deformation in the grinding process, with stronger force for grinding the ore grains, so as to improve the productivity of ball mill. However, the increase in steel ball hardness can only be moderate, and there is a proper range, not the harder the better. If only considering the steel ball consumption, the higher the hardness, the lower the consumption, but for ball mill productivity, within a certain range the productivity increases with the increasing of steel ball hardness, but when the hardness is over the certain range, which is harmful to ball mill productivity and makes it down.

About the influence of steel ball density on the ore grinding, for the same size of steel ball, big density then big productivity, little density then little productivity. The density of steel ball is mainly influenced by three factors.

1.Material quality. The material of grinding ball is usually the steel, cast iron, alloy steel and so on, the density of different material is different, the density of steel is bigger than cast iron, and the density of alloy steel is different depending on the different density and content of main alloy element.

2.Manufacturing method. The structures of rolling steel ball and forging steel ball are dense, so the density is large；The structures of casting steel ball, casting iron ball and casting alloy ball are not very dense, even with the stomata, so the density is small.

3.Metallographic structure. The density of martensite, austenite, bainite, ferrite and other different crystal structures is different, and it also has an effect on the fineness of crystallization.

In summary, choosing the right steel ball for the ball mill is not the pursuit of high hardness. However, for steel balls of the same size, you should give priority to the large-density steel balls, because selecting this type of steel balls can make the production efficiency of ball mill better. For more ore beneficiation equipment, please contact FTM for details.