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When using a ball mill for fine mill, the strength of the ore particles is high, the broken ore particles are small, and the process conditions are difficult to control, the finer mill is low, and the energy consumption is low. Big. Therefore, improving refining efficiency is particularly important. The key to improving fine mill is to greatly increase the area of \u200b\u200bthe mortar. To this end, just use force methods to reduce the diameter of the ball and increase the number of balls. Therefore, in order to carry out fine grinding, the diameter of the ball should be as small as possible while ensuring sufficient grinding force. For ore feeds having a particle size of 0.15 mm, fine grinding balls of 8 to 10 mm in diameter are sufficient.
The ball mill is an important equipment for fine pulverization and ultra-fine pulverization. When working, the material is sent to the pulverized chamber under the action of centrifugation, and then the material in the steel ball and the crushing chamber will strike and grind the material to achieve the purpose of pulverizing, and fine. Therefore, the increase in the temperature of the ball mill is mainly due to the effects of grinding minerals, the mechanical friction of the abrasive material, or the energy released during crushing, or may be caused by too high temperature. Briefly, when the internal temperature of the ball mill is too high, we need to reduce the temperature method to avoid affecting normal production. Please refer to the following three basic cooling methods:1. Strengthen the internal ventilation of the ball mill
This should be a simple method of calculating the cooling air volume of the mill according to the heat balance of the ball mill, but if the air is too large Then the grinding effect will deteriorate economically.
2. Adding watering means
can be sprayed from a grinding head or a grinding. Only when the temperature of the incoming abrasive is higher than 100 degrees, the feed end of the ball mill can be sprayed downstream.
3. Spray water cooling
Cooling in the ball mill is cooled based on cold water outside the ball mill. The compressed air process is used to spray water into the ball mill, which not only utilizes water, but also uses the latent heat of water during the evaporation. Take the heat in the ball mill, but it should be noted that the spray water is about 1% to 1.5% cement, generally no more than 2%, otherwise the water cannot be fully evaporated.
The coarse grinding of the ball mill depends on the impact. It should be ensured that the steel ball and the liner are adhered to a coarse particle, which can make the impact in the impact more effectively. Therefore, coarse grinding should ensure that the pulp concentration is about 75% to 80%. In fine grinding, the ore itself is very fine, some of which are suspended. The viscosity of the slurry itself is very large. The higher concentration of slurry produces a large buoyancy, which has a great impact on finely grinding small diameter steel balls. The relatively thin pulp concentration should be used, about 50% to 65% sufficient.
The coarse pulverization process of the ball mill is large, the pulverization rate is large, and the fine pulverization method and the pulverization rate of small particle size are small. The material of the coarse ball mill has a wider particle size, usually a particle size of about 25 mm, which can reach 20-15 mm. If we grind to 0.15 mm (-0.074 mm is about 80%, the grinding ratio will reach 166-100. The concentrate size is calculated according to 0.30mm, and the product particle size is 0.074mm. You can see grinding ratio, coarse grinding It is much larger than the grinding grinding ratio.
