The grinding methods of planetary ball mills can be roughly divided into wet grinding and dry grinding. Of course, if broken down, there are also low-temperature grinding, high-temperature grinding, protective atmosphere grinding, vacuum grinding, etc. But these grinding methods are essentially classified as wet grinding or dry grinding.
When users of planetary ball mills grind materials, whether they choose dry grinding or wet grinding will have a great impact on the grinding results. How to choose a more appropriate grinding method requires understanding the differences between the two grinding methods.
Wet grinding is a more commonly used method. Compared with dry grinding, its grinding efficiency is higher and the fineness is better. The process of material grinding is that the large particles of the material appear cracks under the friction, shearing and impact of the grinding medium of the planetary ball mill. As the action time increases, the cracks continue to accumulate and break into small particles. During dry grinding, the collision and extrusion between particles and grinding media will cause the cracks to "heal" again, resulting in the failure of small particles to be formed. During wet grinding, liquid grinding aids will enter the cracks to prevent them from "healing", and the formation of small particles will no longer be affected, thereby improving grinding efficiency and fineness.
However, when the planetary ball mill is wet grinding, different grinding aids are needed to prevent them from reacting with the materials and producing other substances during the grinding process, resulting in grinding failure. During the drying process of the material after grinding, crystallization may occur, and the particles gather together to form agglomerates, resulting in a greatly reduced grinding effect. During dry grinding, due to the shape of the grinding jar itself, a certain dead corner will be formed, and the materials in the dead corner cannot be fully ground. It is also not suitable for dry grinding when materials need to be mixed and dispersed.
