Component: Ball mill liner is composed of a metal body (shell), permanent magnet (cover polyaddition magnet) and the elastic layer. 　　Ball mill service life: service life of ball mill liner is 6-10 times of manganese steel liner. Metal protective shell material and production process: Metal protective shell material is developed by our company as a special non-magnetic materials. It is changed from a special military alloy metal with some necessary mental elements, with features of abrasion resistance, acid, alkali, corrosion resistance, strong magnetic permeability and so on. It makes the protective layer have sufficient strength, thickness and ensures adequate service life.