Development status and trend of jet mill

Superfine pulverizing equipment can be divided into: mechanical impact pulverizer, vibration mill, jet mill (also known as jet mill), and agitator mill according to different pulverization methods.

The jet mill is different from other pulverizers in that it is pulverized by the impact of the particles themselves, the impact of the airflow on the material, and the impact, friction and shear of the material and other components under the action of high-speed airflow. . Therefore, the average particle size of the material after gas jet pulverization 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 dispersibility is good; the low melting point and heat sensitive material and the biologically active product can be pulverized (because the air flow is pulverized) The compressor is powered by compressed air, and the adiabatic expansion of the compressed gas at the nozzle will lower the temperature of the system. According to statistics, about 25% of the jet mills in the world are used for ultra-fine preparation of drugs. Further, when a gas such as N 2 or CO 2 is used, pulverization in an inert atmosphere in a special case can be performed. Airflow pulverization can be operated under aseptic conditions; the production process is continuous, the production capacity is large, and the degree of automation and automation is high. However, the production cycle of pulverizing equipment such as mechanical impact pulverizer, vibrating mill, and agitating mill is often long, which results in low production efficiency; a large amount of heat is generated when the material is pulverized, causing the heat sensitive material to deteriorate; and the wear of the equipment may contaminate the product. . Therefore, these mechanical pulverizers have not fully met the increasing demands of ultrafine powder materials, and the airflow pulverizing equipment has a tendency to replace mechanical pulverizers in the production of ultrafine powders. However, there are some shortcomings in airflow grinding: high equipment manufacturing cost, high energy consumption, and high processing cost; single machine processing capacity is poor (yield is less than 2t/h), not suitable for large-scale production; product granularity is difficult to achieve At the micron level, the output is drastically reduced below 10 um, and the processing cost is sharply increased. Since the advent of the jet mill in the 1930s, through the efforts of many researchers, its structure has been continuously updated, and the types are increasing. There have been flat (or disc) jet mills, circulating jet mills, and colliding jet mills. , fluidized bed jet mill, target jet mill, supersonic jet mill, etc.

China's airflow pulverization technology has developed rapidly, and many excellent manufacturers have emerged. At present, the main airflow pulverizer manufacturers at home and abroad are as follows: (1) Domestic: Shenyang Aircraft Research Institute Powder Company, Miyou Group Co., Ltd., Shanghai Fine Powder Equipment Co., Ltd., Sichuan Juzi Super Micro Technology Co., Ltd., Mianyang Liuneng Powder Equipment Co., Ltd., Kunshan Qiangwei Powder Equipment Co., Ltd., Yixing Hongda General Equipment Co., Ltd., Yixing Jingxin Powder Machinery Co., Ltd., Shanghai Sanfen Equipment Co., Ltd., Yingkou Xinyuan Powder Equipment Co., Ltd., Weifang Zhengyuan Powder Equipment Co., Ltd., Weifang Essence Powder Equipment Co., Ltd., Beijing Grefini Technology Co., Ltd., Weifang Huate Powder Equipment Co., Ltd. Qingdao Maier Cologne Powder Equipment Co., Ltd., Weifang Elpai Powder Technology Equipment Co., Ltd., Yixing Dachen Machinery Technology Co., Ltd., etc.; (2) Foreign: Hosokawa Mikron Group, Germany Nichi Company, Germany Akentu Companies and other manufacturers.

There are many types of ultra-fine jet mills with different structures, each of which has its advantages and disadvantages. In recent years, the pulverizing equipment has been greatly improved on the basis of the previous ones, and its structure has been continuously improved, and the pulverizing performance has been continuously improved. In order to meet the higher requirements of information technology, biotechnology and new material technology development on the particle size, purity and particle size distribution of powder products, the research on ultra-fine airflow pulverization technology should focus on the following aspects: the existing foundation Improve and optimize ultra-fine airflow pulverizing equipment, develop new equipment, and pay attention to the matching design of crushing and grading system; there are not many large-scale equipments. In the above-mentioned ultra-fine airflow pulverizer, in comparison, fluidized bed colliding The type of jet mill has obvious advantages. Therefore, theoretical research should be strengthened to guide the design of the crushing equipment. Since the biggest disadvantage of the jet mill is the low energy utilization rate, it should seek ways to reduce energy consumption and increase energy utilization.