International ore dressing professor said that there has a certain relationship between specification of steel ball and granularity of being ground material which used in lime ball mill, that is to say the larger granularity of material, the larger average diameter of steel ball mill. It shows that fully use big diameter grinding media and fully use small diameter grinding media are not suitable for ball mill, it must have both impact ability and grinding ability to achieve the goal of high quality, high output and low consumption.

Steel ball diameter size combines with its quality called grinding media grading, grading is determined by physicochemical property of being ground material and the structure of lime ball mill and fineness requirement of final product. Therefore, the grading of lime ball mill has directly influence on its output and consumption of grinding media.

In summary, the material is large at the beginning when lime ball mill is running, hence, it need larger diameter steel ball to impact. With the decrease of material, the small steel ball is needed to increase grinding ability. Under the same loading capacity circumstance, decreasing grinding media size can increase contact area and improve grinding ability.