Abstract: The purity of kaolin powder is decreased due to a lot of introduced other impurities by traditional wet treatment technology and mechanical wear in general ultrafine preparation process. In order to avoid above conditions, the Mianyang Liuneng Powder Equipment's mechanical energy mill (LNI-330A type) was used to prepare ultrafine kaolin powder in this experiment under the condition of dry type. Through the orthogonal experiment, the optimum condition: the classifier speed is 1 087 r/min, the grinding speed of main engine is 120 m/s, the total system air volume is 5 400 m³/h, the secondary air flow of second stage classifier is 465 m³/h, the main stream flow is 3 523 m³/h. Under this condition, the production yield of kaolin powder is 397 kg/h. The analysis of laser particle analyzer and scanning electron microscope shows that the particle size (d₅₀) of kaolin powder is lower than 4 μm, the ordered microstructures and morphology stereotyping of kaolin powder are formed.

Key words: Mechanical energy mill, Kaolin, Ultrafine grinding