Different from other pulverizers, airflow mill smashes materials through the impact between its own particles, the impact and shear of airflow on materials, and the impact, friction and shear of materials and other parts under the action of high-speed airflow. Therefore, after air flow crushing, the average particle size of the material is fine, the particle size distribution is narrow, the particle surface is smooth, the particle shape is regular, the purity is high, the activity is large and the dispersion is good; It can crush low melting point and heat sensitive materials and bioactive products (because the air mill is powered by compressed air, the adiabatic expansion of compressed gas at the nozzle will reduce the system temperature). Moreover, if N2, CO2 and other gases are used, it can be crushed in inert atmosphere under special occasions.
Airflow crushing can be operated in sterile state; The production process is continuous, the production capacity is large, and the degree of automatic control and automation is high. However, the production cycle of crushing equipment such as mechanical impact crusher, vibration mill and stirring mill is often long, resulting in low production efficiency; A large amount of heat will be generated during material crushing, resulting in the deterioration of heat sensitive materials; Moreover, the wear and tear of the equipment will pollute the product. Therefore, these mechanical pulverizers can not fully meet people's higher and higher requirements for ultra-fine powder materials. Air flow pulverizing equipment has the trend to replace mechanical pulverizers in the production of ultra-fine powder. Since the air mill came out in the 1930s, through the efforts of many researchers, its structure has been continuously updated and its types have been increasing. There have been flat (or disk) air mill, circulating air mill, collision air mill, fluidized bed air mill, target air mill, supersonic air mill and so on.
There are many kinds of ultra-fine airflow mills with different structures. Each model has its advantages and disadvantages. In recent years, the crushing equipment has been greatly improved on the previous basis, its structure has been continuously improved, and the crushing performance has been continuously improved. In order to meet the higher requirements of the development of information technology, biotechnology and new material technology for the particle size, purity and particle size distribution of powder products, the following aspects should be paid attention to in the research of ultra-fine air flow comminution technology: on the existing basis, improve and optimize ultra-fine air flow comminution equipment, develop new equipment, and pay attention to the matching design of comminution and classification system; There are few large-scale equipment. In the above-mentioned ultra-fine airflow mill, the fluidized bed impinging airflow mill has obvious advantages. Therefore, theoretical research should be strengthened to guide the design of crushing equipment; Because the biggest disadvantage of air mill is low energy utilization, we should find ways to reduce energy consumption and increase energy utilization.