Size reduction is an important part of many industrial processes, making ball mills and other pulverizing mechanisms vital to these industries and in high demand. Particularly in processes that involve the mixing of materials, the smaller the particulate size of the materials to be mixed, the easier and more complete the mixing will be. Ball mills are useful tools for metal alloying processes for this reason; they can crush and grind the constituent materials into very small particles, which makes them easier to combine.
Ball mills are also used for the particle size reduction of black powder, cement, fertilizer, silicates and even a variety of ferrous and non-ferrous metals. Ball mills are very similar in design and operating concept to rock tumblers, which used milling media to polish rocks in a rotating cylinder.
Ball mill machines usually include a cylinder, a motor and crushing media. The cylinder is where the crushing happens. The material intended for crushing is fed into the cylinder along with crushing media. Crushing media can be composed of many materials; a few examples include lead-antimony alloys and steel as well as non-metals like flint and ceramics.
When the crushing media and material to be crushed are combined in the cylinder, the cylinder is rotated by a powerful motor. As the cylinder rotates, the crushing media are thrown about the cylinder, smashing the material to be crushed as they move. After enough time has passed, the materials become crushed into very small particles. Once sufficiently crushed, the materials can be discharged from the cylinder and replaced with new materials to be crushed.
This process can be carried out in batches, or it can be continuous. Continuous ball milling involves the ongoing automatic loading of materials to be crushed and unloading of crushed materials. Depending on the scale of the milling operation, ball mills can be small enough to fit on work benches or large enough to take up entire rooms.