1.Material situation

•   Material properties

 The grindability coefficient is related to the mechanical strength of the ore, the embedded characteristics and the grinding ratio. The harder the ore is, the less grindable it is. Grinding it requires more energy and the processing capacity of the ball mill is also lower. In addition, the properties of the minerals in the ore are also different, including those that are easy to grind and those that are difficult to grind, so there will be a phenomenon of selective grinding, that is, part of the minerals have not been ground, but the other part has been crushed. For tungsten that is afraid of being crushed, Special attention should be paid to tin ore, and the finely ground parts should be separated out in time. The finer the ore, the more difficult it is to grind. As the grinding ratio increases, the grindability coefficient will also change. The grindability of mineral materials generally cannot be changed, but recent research results have shown that in some special cases, preheating the ores, irradiating them with electric heat, or using surfactant agents can significantly change their grindability. Some of the grinding properties have been used in production practice, which not only reduces the number of grinding and magnetic separation stages, but also improves the concentrate index.

• Material particle size

 The coarser the ore fed by the ball mill, the longer the grinding time required, the more work it takes to grind it to the specified fineness, and the lower the productivity. The impact of changes in feed particle size on ball mill productivity is related to ore properties and product fineness. Therefore, when it is required to increase the production capacity of the ball mill, reducing the feed particle size within a certain range has a significant effect.

• Product fineness

 The particle size of ball mill grinding products directly affects the sorting index. The particle size of the grinding product is too coarse, and the useful minerals and gangue are not fully dissociated. If the particle size is too fine, it will cause serious over-grinding. Both situations will reduce the separation index. If the grinding particle size is changed to finer, energy consumption and steel consumption will increase, productivity will decrease, and the cost per ton of ore ground will be higher than when grinding coarser ore. Therefore, the determination of grinding particle size must be based on comprehensive consideration of technical and economic conditions.

2. Structure and speed of ball mill

• Type of mill

• Mill diameter and length

• The speed of the grinding machine

• Lining type