The ball mill jar is one of the grinding kits of the planetary ball mill used in the laboratory, where the sample to be ground and the grinding ball are placed. There are many types of ball mill jars. According to the grinding mode, they can be divided into horizontal ball mill jars, vertical ball mill jars, vacuum ball mill jars, etc., and according to materials, they can be divided into stainless steel, nylon, agate, corundum, polyurethane, zirconia, Silicon carbide, polytetrafluoroethylene (PTFE), etc.
 
Generally speaking, different types of samples need to use ball mill jars made of corresponding materials to ensure the grinding effect of the samples, so how do we choose a ball mill jar of suitable material for planetary ball mill?
 
Principles for the material selection of the ball mill jar of planetary ball mill
In general, when choosing a ball mill jar, we usually consider its hardness and corrosion resistance, and whether it causes pollution or it can be used for vacuum grinding.
 
The first to be considered is the hardness. The hardness of the sample needs to be smaller than that of the ball mill jar and the grinding ball, otherwise the sample will wear the ball mill jar and the grinding ball during the ball milling process, resulting in pollution to the sample, at the same time, failure to achieve a good grinding effect, so we are choosing the ball mill jar and the grinding ball, a ball grinding jar and a grinding ball with a hardness equal to or greater than the hardness of the sample are better. Among the several ball mill jars commonly used today, in order of hardness from high to low, they are silicon carbide, zirconia, agate, corundum, and stainless steel.
 
The second is corrosion resistance. In the laboratories of food, medical, and beauty industries, there will be some strong acid and alkali samples, which are strongly corrosive. If you choose a ball mill jar with an inappropriate material, it will be corroded and damaged, and even contaminate the sample. For corrosive samples, we generally choose ball mill jars made of polymer materials such as polytetrafluoroethylene (PTFE) and polypropylene (PP), so as to prevent the samples from corroding the jar.
 
Finally, we should consider whether the ball mill jar will contaminate the sample. When using the ball mill, we must not only see the effect of the material size, but also pay attention to whether the sample will be contaminated due to the ball mill jar during the ball milling process, so as to prevent other impurities from being mixed into the sample and affecting  the experimental results.
 
In addition, in some special cases, some samples should avoid contact with oxygen and other gases in the air during grinding, so vacuum ball milling method or inert gas ball milling method is required. At this time, it is necessary to use a special vacuum ball mill jar, which is generally made of stainless steel. If the sample cannot be contaminated by metal or will corrode stainless steel, we need to embed other materials on the inner wall of the vacuum stainless steel ball mill jar to avoid direct contact between the sample and the stainless steel while realizing vacuum grinding.
 
The above is the selection principle of the ball mill jar for planetary ball mills used in the laboratory. There are many types of ball mill jars. Therefore, we should consider the above four aspects when selecting and using it to achieve a good grinding effect.