After the ball mill starts to run normally, add steel balls (3 for120mm, 4 for100mm and 3 for 80mm) according to the ratio of 3: 4: 3. Note: the addition of small steel balls is only the first time to add balls. Because, in the normal operation of drum ball mill, reasonable grinding between steel balls, between steel balls and ore, and between steel balls and ball mill liner will increase wear and tear, which will make the large ball mill smaller (ground into middle balls) and the middle ball mill smaller. So in general, you don't need to add balls. In the case of adding pellets, there is no monomer dissociation in the particle size of useful minerals. When the fineness of the mill can not meet the flotation requirements, an appropriate amount of pellets can be added. The steel balls in the ball mill are constantly worn during operation. In order to maintain the ball load filling rate and reasonable ball ratio and maintain the stable operation of the ball mill, it is necessary to replenish the balls reasonably and reduce the wear. The addition weight of steel balls is determined according to the quality of steel balls and the quality of steel balls. It is best to use new wear-resistant steel balls. The best (good quality) steel ball addition is calculated according to the throughput per ton of ore (that is, 0.8㎏ per ton of ore). Generally, it is necessary to treat one ton of ore with steel balls (1-1.2). Steel ball size ratio: Different ball mill models have different ratios. The diameter of the ball mill is below 2500㎜, and the added steel balls are 100㎜, 80㎜ and 60㎜. The diameter of the ball mill is over 2500㎜, and the added steel balls are 120㎜, 100㎜ and 80㎜.