The laboratory planetary ball mill adopts the working principle of planetary operation. Compared with the traditional ball mill, its grinding effect is greatly improved, and it has received more attention in recent years. When some samples in the laboratory are processed before grinding, because of their physical and chemical characteristics, it is often necessary to control the upper temperature limit to avoid changes in their properties. When the planetary ball mill is working, the grinding balls in the ball mill tank will undergo high-frequency impacts and strong friction, which will generate a lot of heat and affect the samples.
 
In order to maintain the low temperature operation of the planetary ball mill, certain methods are required. Here are three commonly-used methods for cooling the ball mill tank of the planetary ball mill.
 
Three methods of low temperature operation of planetary ball mill:
I. Pre-freezing of ball mill tank
Since the sample is ground in the ball mill tank, we can pre-freeze the ball mill tank before grinding. For example, place the ball mill tank in a liquid nitrogen environment to cool down, and then put in the sample for grinding. In this way, the ball mill tank can be controlled within a certain temperature range. However, this method is only suitable for the rapid grinding within a few minutes, because the temperature of the ball mill tank will gradually rise as the grinding time increases.
 
II. Make refrigerant gas through the working part to create a low temperature environment
The working part of the planetary ball mill is a big wheel with four ball mill tanks rotating. We can cover the working part with a cooling cover, and then make refrigerant gas (such as liquid nitrogen) get into the cooling cover to make the ball mill tank In a continuously low temperature environment. Due to the low temperature around the ball mill tank, the heat generated in the tank body will slowly dissipate, so as to achieve the effect of cooling the tank body. However, the wall of the ball mill tank is usually thick, so this method has low cooling efficiency and cannot control the temperature in real time.It just get little effect in actual use, and is only suitable for some samples that have less strict requirements on the grinding temperature.
 
III. Use a special temperature-controlled ball mill tank
In fact, cooling the tank body is a more direct and effective method. In order to solve the problem of the thickness of the tank that affects the cooling effect, a temperature-controlled ball mill tank can be used. This kind of ball mill tank has an inter-layer between the inner core and the outer shell, and absolute ethanol can be continuously passed through when grinding samples to take away the heat continuously generated by the ball mill tank, thereby reducing the temperature in the tank body. The temperature-controlled ball mill tank reduces the contact distance between the refrigerant and the heat source, and adopts water cooling, a more effective cooling method, which truly achieves the effect of real-time temperature control during the grinding process.