The bulk materials are crushed to the required particle size by the crusher and sent to the storage hopper by the elevator. The materials are quantitatively and continuously sent to the main machine for grinding by the vibrating feeder. The milled powder rises with the air flow of the centrifugal fan and enters the powder concentrator for classification. The powder meeting the fineness standard flows through the pipeline and enters the cyclone powder collector for separation and collection, The finished powder is discharged through the discharge valve. The air flow enters the centrifugal induced draft fan from the return air pipe at the upper end of the cyclone powder collector. The whole air flow system is closed and circulates under positive and negative pressure. An exhaust pipe is added at the outlet of the centrifugal induced draft fan to discharge the excess gas into the dust collector for filtration, and then discharge the clean gas to realize environmental protection production.