Magnetic separation is a method to separate and capture fine magnetic particles by the magnetic force acting on the particles in a gradient magnetic field. For the practical use of the magnetic separation, it is necessary to remove the captured particles from the separation area where the magnetic force is active. High gradient magnetic separation utilizes the high spatial magnetic field gradient generated in the matrix of fine ferromagnetic wires (filter matrix) magnetized by an applied magnetic field. In batch-type magnetic separation, the filter matrix is washed by water flushing and by reducing the applied magnetic field to remove the captured particles in the filter matrix. When the particle content in the slurry is large, the short cycle of the water flushing of the filter matrix results in a decrease in separation efficiency. The frequent interruption of the separation process for the flushing is a problem for the practical magnetic separator. Therefore, from the viewpoint of the practical application of magnetic separation, a continuous separation process without interruption for the flushing is useful. In this paper, recently developed magnetic separators for continuous process are reviewed, and their mechanism is explained.
