Ball mill is mainly used for grinding materials in such production industries as cement, silicate product, new building materials, corhart, chemical engineering, nonferrous and black metal, mineral processing, glass and ceramic, etc. It is used for grinding various ore and other grindable materials dry or wet.
Dry Grinding Ball Mill
Ball mill grinding is a principle and cylindrical revolving device, and belongs to external gear-driving ball mill. The materials are transported by feeder, and gets into mill chamber through hollow screw axis equably, and there is lining plate and steel balls in the chamber. When the cylinder body goes round and round, the steel ball is taken to certain height, then falls down, and the materials are struck and grinded heavily. The above action repeats constantly till the size of materials reaches the required fineness. The powdery materials are discharged through discharge grate plate, and the milling work is over.
Ball mill Grinding mainly consists of feeding part, discharging part, gyre part, transmission part (decelerated machine, small transmission gear, motor, electric control) and so on. The hollow axis adopts cast steel, the lining plate can be replaced, the big gyre gear is made of forging rolling gear, and there is lining plate in the cylinder body, which has favorable abrasion resistance. The ball mill has the features of stable running and reliable working.
Wet Grinding Ball Mill
The void volume between the grinding media, with the mill half charged, represents approximately 20% of the total volume of the ball grinding mills.
Fastest grinding occurs where there is just sufficient material in a batch to fill all voids and slightly cover the grinding media. The material should never be allowed to drop below the surface of the grinding media, because when this happens, excessive wear occurs to the mill and grinding media and contaminates the material itself. The largest size batches should not exceed 60% of total mill volume.
We should establish the batch size consistent with the allowable running time. It is recommended to do a little experimentation with the batch size to try to develop a system that will work out best under particular grinding conditions. The one principal rule to remember is that the grinding media must be covered with material.
Viscosity - The most important element in wet grinding is the viscosity of the batch. Low viscosity materials permit the grinding media to move with excessive speed and this may cause abnormal wear, contamination and heat build-up. If the low viscosities cannot be avoided then it is imperative that small grinding media be used.
With high viscosities free movement of the grinding media is impeded. This can cause a carrying over and "throw" of the media resulting in inefficiencies and contamination.
