Magnetic particles in magnetic separator magnetic field, in addition to the role of magnetic force, but also by the role of competitiveness. Competitiveness can be defined as the force of all mechanical forces in the opposite direction of magnetism, including gravity, centrifugal force, inertia force and hydrodynamic resistance. In the magnetic separation process, magnetic force is to catch magnetic particles, also known as magnetic trapping force, competitiveness is to make magnetic particles out of the magnetic Pole force, also known as the Detachment Force. Obviously, the necessary condition for separating magnetic particles from non-magnetic particles is that magnetic particles are more magnetic than competitive. In order to separate two different kinds of magnetic particles, the necessary condition is that strong magnetic particles should be more magnetic force than competitiveness, the weaker magnetic particles should be less than competitive force. Need to explain, in the magnetic separation practice can not be absolutely pure magnetic products and non-magnetic products, in addition to the intergrowth of the monomer solution to affect product purity, some monomer magnetic particles mixed in non-magnetic products, some monomer non-magnetic particles into magnetic products. In the former case, the recovery of the magnetic component decreases, the main reason is that the particle size of these magnetic particles is too thin, magnetic force is not enough to overcome the resistance of fluid and other competitiveness; the latter situation led to the decline in the grade of magnetic products, most of the reason is that there is a strong interaction between particles, particle size of the finer, slurry concentration, The interaction force between particles is more obvious.

The electromagnetic coil can cause magnetic separator's iron core and magnetic poles to be magnetized and generate magnetic field around them. Magnetic field between the magnetic poles makes the ore particles magnetized, showing magnetism, and then producing magnetic force, and the non-magnetic ore grains can only receive weak magnetic force, which is not visible to the naked eye, thus leading to the separation of magnetic ore particles and nonmagnetic ore grains. Therefore, further understanding of the magnetization of the material, including the structure of the magnetic material, the behavior in the magnetic field and the measurement of magnetization, is essential to the understanding of the nature of the magnetic separation process.