Three-rings and Medium-speed Micro Powder Grinder mill is a new product developed by our company, it is the domestic advanced dry type fine grinding equipment for non-mental super-fine povwder. The material's crushing and powder's classification are putted in one machine rather than runs alone. Advantages: compact structure, adjustable final fineness(from 400-3000 meshes), easy maintenance, low unit product consumption, low investment and so on. The mate rial's crushing and product's classification are proceeded in one closed system, dusty air is handled by dust collector, so there is no pollution. It is the ideal environment protection equipment. This machine is suitable for super fine grinding for all kinds offragite and non-flammable and non-explosive material whose Moh's hardness is below 5 grade, such as calcium carbonate, barite, aedelforsite, kaoline, rare earth ore, hematite, talcum, feldspar, slag and so on. Compared with traditional Raymond mill, it has advantages of fine product, low energy consumption, is the ideal equipment of dry type calcium carbonate super fine powder grinding.