Ball mill steel balls, grinding balls in the crushing operation, the grinding quality and fineness of the ore is directly related to the purity and quality of the output material.   

The variation of ball mill table hourly capacity with ore dressing grade in each plant is greatly related to the nature of the ore and the means to improve the concentrate grade. In the beneficiation process is basically fixed, the ore has been ground to a certain size, and then rely on the fine grinding measures to improve the concentrate grade, the ball mill table capacity is bound to be reduced. If it is in the continuous improvement, improve the process on the basis of improving the grade, ball mill table capacity may not be reduced, and even have different degrees of improvement. 

Before individual processing plant adopts fine screening, it mainly relies on reducing the grinding size to improve the quality of iron ore concentrate. However, due to the different nature of ore, ore grindability varies greatly, although in the same ball mill grinding size, the useful minerals and vein minerals are not the same degree of monomer dissociation, can only make most of the minerals monomer dissociation, and therefore inevitably make a small amount of congeners and over-crushed minerals exist in the grinding products, affecting the improvement of the concentrate grade. In order to obtain high grade concentrate, it is necessary to adopt the method of reducing the mill capacity, improving the grinding size, reducing the number of congeners, so that the useful minerals and vein stones are fully dissociated. The higher the concentrate grade required, the finer the grinding size required, and the more serious the over-crushing phenomenon. For example, the concentrate grade increased from 65.13% from July to December 1976 to 66.35% from July 1977 to June 1978, and the ball mill capacity decreased from 62.48t/(unit/h) to 53.40t/(unit/h), a decrease of 9.08t/(unit/h).