How fine the high-energy planetary ball mill can grind, you need to pay attention to the following conditions:
The main ones are: material properties (strength, brittleness, hardness, softness, toughness, corrosion resistance), solvents, grinding aids, ball diameter, ball-to-material ratio, rotational speed, ball milling time, etc.
At present, the planetary ball mill on the market can achieve D50400~600nm, which is very good. If it is required to achieve a particle size of tens of nanometers, then only a sand mill can be used. In addition, it also largely depends on the primary particle size and brittleness of the raw material.
If it is required to achieve 500nm, this requires:
1. Find a good ratio of balls to materials, including the ratio of large, medium and small balls
2. Find a good grinding aid, such as ethanol or something
3. To add surfactant, 13 sodium methanesulfonate or something
4. The rotational speed is not as fast as possible. The moderate rotational speed is the so-called optimal grinding speed. If it exceeds the critical value, it may cause problems if it is too fast. If the ball does not fall down, it will not be effective.
5. Choose a good ball mill, planetary or vibration, and the grinding method. The wet grinding effect is better than the dry grinding. The particle size that can be ground is related to the diameter of the zirconium ball used and the hardness of the material. It is recommended to use larger zirconium balls for coarse grinding, and then use small zirconium balls for fine grinding.
6. Post-processing is very important. Your filtration method and drying method will affect the final particle size. In many cases, it is ground fine, but it is reunited when it is filtered and dried. It is recommended to consider centrifugation and freeze-drying.
