The particle stream leaving the reduction chamber flows to the classification zone. As the stream enters the classifier, the direction of the flow is reversed. Properly sized product is entrapped by the exhaust flow and conveyed to collection equipment. Larger particles remain in chamber for further grinding. With classification mills, air or inert gas is injected through specially designed nozzles directly into the grinding chamber of the mill.
Raw material is introduced into the mill.
Size reduction is accomplished by collisions between particles. Small particles are then swept towards the classifier, which rotates at high speeds above the grinding chamber. Material, which is fine enough to pass through the classifier, is collected as product. Oversized particles are recycled, by the classifier, back into the grinding chambers for further reduction. This technique can be relatively simple and fast, making such methods ideal for in-process testing.