1. Select the material of grinding balls.

Material selection takes into account the density, hardness and chemical properties of the material to be ground. 

Generally speaking, you must choose a grinding ball with a larger density and hardness than the raw material to achieve the grinding effect. 

In addition, when the ball mill is working, a large amount of heat is generated in the ball mill due to friction and collision. Therefore, it is necessary to select a grinding ball with good thermal stability and ensure that it does not react physically or chemically with the material to be ground to avoid contamination of the sample.

2. Size selection.

The grinding balls perform different functions depending on the size of the sphere. 

The large ball has a large weight and has a strong impact on the material. It is easy to crush the material, but it is difficult to grind and easily produces dead corners. 

The small ball is small in size and has many collisions, so it has a strong grinding effect on small materials, but its impact force is small, making it more difficult to grind large materials. Therefore, in order to ensure sufficient crushing and grinding of raw materials, grinding balls of different sizes need to be added at the same time.

3. Quantity ratio.

Because large and small balls have different functions, the number must be reasonably allocated. First, calculate the surface area according to the diameter of different grinding balls, and then make the total surface area of different grinding balls roughly equal.

4. Filling space ratio.

During the ball milling process, we must obtain a certain space in the ball mill water tank to function effectively, so it cannot be too full. In addition, in order to achieve good ball milling results, it is recommended that the mass ratio of grinding balls and raw materials be kept between 0.9 and 1.1.