They are made of high purity and super-fine raw material ith the application of the most advanced technology in the world. They can be mainly used to grind and disperse super-fine powders. Meanwhile, they have some very special advantages such as wear-resistance, erosion-resistance, high-density, high-strength and toughness, high-hardness, magnetism-resistance and so on. They can be used in electronics industry, chemical industry, machine industry, ceramic industry, food industry and pharmacy industry etc. And also, they can be very suitable to comminute and rub some raw materials with high purity such as alumina, alucomminute hydroxide, zirconium silicate, calcium carbonate, kaolin, varnish, printing ink, dope, electronic ceramic powder, medicine, food etc. This kind of product will never contaminate the environment and can avoid contaminating the raw material. Therefore, they can guarantee the purity of the raw material.