Magnetic separator is one of the most widely used and versatile machines in industry, which is suitable for the separation of substances with magnetic differences. Magnetic separators are widely used in mining, timber, kiln, chemistry, food and other industries. As far as mining is concerned, magnetic separators are suitable for wet or dry magnetic separation of manganese ore, magnetite, pyrrhotite, roasted ore, ilmenite, hematite and other materials with particle size below 50mm, and are also used for iron removal of coal, non-metallic minerals, building materials and other materials. Magnetic separators are divided into two categories. The magnetic system of permanent magnetic separators is mostly made of high-quality ferrite materials or compounded with rare earth magnetic steel. Earlier, the average magnetic induction intensity on the surface of magnetic cylinder of magnetic separators was 80-400 mt. With the continuous development of technology, after the magnetic separator can be made into a roll shape, the magnetic field intensity has also increased to 1650mT, which is the highest measured magnetic field intensity at present.