POWDER CLASSIFYING METHOD

摘要

PROBLEM TO BE SOLVED: To to sort powder into a passable size powder and a non-passable size powder through an opening in a rotary member with an opening by adding a metallic compound of salicylic acid to the powder and causing the passage of gas in which the powder is dispersed through the opening. SOLUTION: Powder to be sorted is caused to contain a metallic compound of salicylic acid. The mold release effect of the metallic compound of salicylic acid helps mitigates the stickiness of the powder to a rotary member. The metallic compound of salicylic acid is a trivalent metal which can be used as a metallic component. When a classifier to be used is of the crushing counter- jet mill AFG type, plural compressed air nozzles 2 are provided at the lower part of the container. The powder piling in the container is crouched by entrapping the powder into a gas jetted from the nozzles 2 and the powder crushed to the desired size is sucked by a blower through a rotating rotor 3 located at the upper part of the container. The powder passes through the rotating rotor 3. The particle of large size is returned by the rotating rotor part and then drops downward to be further crushed.