Under the action of magnetic field in the ball mill Magnetic lining plate form cushion broken balls and magnetic minerals of 20~30mm, they are absorbed so firmly on the metal protective shell surfaces that avoid direct conflicts between the ball and its materials with surface of the magnetic lining plate. Magnetic lining plate has a long life due to the work surface is protected by ore bed. Now Sichuan gaodete technology technology co., ltd is the only company in southwest China engaged in the research and development of magnetic lining project.