The hydro-cyclone is a grading device that uses centrifugal force to accelerate the sedimentation of ore particles. It requires pressure to mine, so it consumes a lot of power, but it has a small footprint, low price, large processing capacity, high classification efficiency, and can obtain very fine overflow products, which are mostly used for classification work in the second stage closed-circuit grinding. Sometimes used for mud dewatering, divided into pressure and gravity, often made of cylindrical structures or metal tubes.