How to choose the grinding media ball of the ball mill?

During the use of the ball mill, the choice of grinding media is very important. Grinding media is affected by many factors such as material, filling amount, shape, particle size, etc. In the grinding process, using different grinding media for different materials, models, and equipment can reduce production costs and improve production efficiency.

Media density, hardness, size

The greater the density of the grinding media, the shorter the grinding time. In order to increase the grinding effect, the hardness of the grinding medium must be greater than the hardness of the material to be ground. According to long-term experience, the Mohs hardness of the medium is better than the hardness of the material to be ground by more than 3 levels. In addition, the smaller the size of the grinding media, the more media contact points, and the more opportunities for grinding materials.

Media filling quantity

The filling quantity has a direct influence on the grinding efficiency, and the particle size of the grinding media determines the filling quantity of the grinding media. It must be ensured that when the grinding medium moves in the disperser, the void ratio of the medium is not less than 40%.

For different fineness requirements, it is necessary to adjust the capacity distribution of grinding media for crushing and grinding, with high filling rate and strong grinding ability. High filling rate is generally used for superfine grinding.

Material

The grinding material determines the cost and efficiency of grinding. Grinding materials can be divided into three types: metallic media, rock mineral materials and non-metallic materials. In addition to considering the production cost, the choice should also consider whether the materials and media will cause pollution.

Commonly used grinding media include steel balls, alumina balls, and zirconia balls.

Shape and size

Grinding media are generally spherical, because other irregularly shaped media will wear themselves and cause unnecessary pollution. The size of the medium directly affects the grinding efficiency and the fineness of the product. The larger the diameter, the larger the product particle size and the higher the output; on the contrary, the smaller the medium particle size, the smaller the product particle size, and the lower the output. In actual production, it is generally determined according to the feed size and required product fineness.

Media ratio

Generally speaking, in the continuous grinding process, the size of the grinding media is distributed regularly, and the size ratio of the media is directly related to the big problem of whether the grinding ability can be exerted and how to reduce the wear of the media. In the process, the fixed media ratio will not always be maintained. In the production, the method of supplementing large balls is often used to restore the grinding of the system. It is difficult for the mill to maintain a fixed medium ratio for a long time, and the medium diameter difference is too large It will aggravate the ineffective grinding between the media and increase the cost of the grinding process;

In the production process, it is necessary to explore the appropriate ratio according to the type of material and process characteristics, and remove the medium that is too small in time to reduce the cost.

Abrasion resistance and chemical stability

The wear resistance and chemical stability of the grinding media are important conditions for measuring the quality of the grinding media. The non-wearable media needs to be supplemented due to abrasion, which will not only increase the cost, but also affect the production.

In the specific grinding process, the grinding medium needs to have a certain degree of chemical stability, and cannot chemically react with the material during the grinding, causing pollution to the material.