In the magnetic field of the magnetic separator, the magnetic particles are not only affected by the magnetic force, but also by the competitiveness. Competitiveness can be defined as the resultant force of all mechanical forces opposite to the direction of magnetic force, including gravity, centrifugal force, inertial force, and hydrodynamic resistance. In the process of magnetic separation, magnetic force is the force to capture magnetic particles, also known as magnetic capture force; competitiveness is the force to make magnetic particles detach from the magnetic poles, also known as detachment force. Obviously, the necessary condition for separating magnetic particles from non-magnetic particles is that the magnetic force received by the magnetic particles is greater than the competitiveness.
To separate the two particles with different magnetic properties, the necessary condition is that the stronger magnetic particles should receive more magnetic force than the competitiveness, and the weaker magnetic particles should receive less than the competitiveness. It is required to clarify that in the practice of magnetic separation, it is impossible to have pure and pure magnetic products and non-magnetic products. In addition to the undissociated conglomerates that affect the product purity, some monomer magnetic particles are mixed into non-magnetic products, and some monomers are not. The magnetic particles are mixed into the magnetic product. The former situation leads to a decrease in the recovery rate of magnetic components. The primary reason is that the particle size of these magnetic particles is too fine, and the magnetic force is not enough to overcome the competitiveness of fluid resistance; the latter situation leads to a decline in the grade of magnetic products, mostly due to particles. There is a strong mutual effect between the particles. The finer the particle size and the greater the slurry concentration, the greater the mutual effect between the particles.
The electromagnetic coil can magnetize the iron core and magnetic poles of the magnetic separator, generating a magnetic field around it. The magnetic field between the magnetic poles magnetizes the ore particles, causing magnetism, and then generates magnetic force; non-magnetic ore particles can only receive a weak magnetic effect that cannot be detected by the naked eye, and then cause the separation of magnetic ore particles and non-magnetic ore particles. Therefore, further understanding of the magnetization of materials, including the structure of magnetic materials, their behavior in the magnetizing magnetic field, and the measurement of the degree of magnetization, is indispensable for understanding the essence of the magnetic separation process.