The material is fed into the feed port of the rotating separator at a constant speed by the automatic feeder, and is guided into the first grinding chamber by the guide screw in the feed port. With the rotation of the cylinder in the grinding chamber, the materials and grinding media are continuously lifted and dropped. During the process of lifting and falling, the aluminum ash is crushed by the impact, collision, grinding and shearing of the grinding media. With the increase of materials and the cylinder itself has a certain angle, the materials and media are constantly moving towards the discharge end while the cylinder is rotating, and the grinding medium and large particle materials are separated by the bulkhead. Fine materials enter the second grinding chamber through the gap on the bulkhead, repeat the above actions, and finally discharge out of the machine. Due to the good calenderability of metal, the metal aluminum particles in the discharged material are relatively large, and the impurities are ground into very fine powder, which provides favorable conditions for the next process - screening.