Abstract: To cope with the problems regarding superfine pulverizing of flammable, explosive and oxidative materials, We have successfully developed the inert gas circulation jet mill system based on the explosive features of flammable powder and the inert gas explosion proof principle. The study is intended to analyze the characteristics of the process, device and structure of the system, and investigate its applications in chemical, pesticide, metal, rare metal, new energy and other industries, to realize the safe, environmental, energy saving and high quality production.

With the advancement of modern sciences and technologies and the development in the high-tech, new energy and other strategic emerging industries, more and more high performance materials are used, e.g. the superfine powder, due to the small particle size, large specific surface area, high surface activity, etc. The jet milling system is one of the most effective equipment for the dry preparation of superfine powder, in which the fluidized bed jet mill is the type used most widely in the dry superfine pulverization of many materials, with the particle size and the sizes distribution meeting the requirements, available for the high performance applications. Our jet mill machine has been used for pulverizing the Herbal medicine (D50=2µm), improving the absorption rate and the utilization rate; the pharm of Clotrinazole (D97=9.88µm), significantly improving the efficacy; Sulfur (D97=15µm), obtaining the higher catalytic reaction speed; Nonferrous metal powders as Nickel and Cobalt (D97=10µm), with the more uniform mixing; Carbon Black (D50<2µm) for Lithium cells, Zirconite (D95=2µm) for fine ceramic, etc.

Now flammable, explosive and oxidative products used in many fields of the modern industries feature the superfine particle size and the higher risk of explosion, because oxidation or explosion may occur when such products are pulverized with air as the medium, and the smaller powder size is, the lower explosion limit (LEL) is, and the lower minimum ignition energy is.

According to the requirements of "China 12th Five-Year Plan”, the manufacture shall be conducted in the safe, explosion proof, environmental, energy saving and clean manner, with the new processes and new formulas, and in the continuous and automatic process. For the manufacture of powder products, the superfine pulverization of flammable, explosive and oxidative materials is a particularly urgent problem to be solved. The inert gas circulation jet mill system first successfully developed and has been used, with inert gases as the milling media, for the superfine pulverization of nickel powder, cobalt powder, zinc powder, Nd₂Fe₁₄B, Al(H₂PO₂)₃, NQ, 5-Amino-1H-tetrazole, Sulfur, LiFePO₄, VC, sucralose powder and other materials, with the pulverizing particle size (D97) of 2-15µm. The system is widely used in Chemical, Pesticide, Pharmaceutical, Metal, Rare metal, New Energy and New Materials and other industries, and has been accredited as an independently innovative product in China.

Inert Gas Circulation Jet Mill Micronizing System

process flow of nitrogen gas circulation milling system