Abstract :
A theoretical model of magnetic flocculation of weakly magnetic minerals is presented. A threshold magnetic field at which magnetic flocculation begins is derived, and the dependence on particle size, magnetic susceptibility, and other factors characterizing the mineral suspension are examined. Stability ratios and flocculation rates computed from the model indicate that magnetic flocculation commences provided the total energy of interaction of particles is zero, and simultaneously the flocculation time is reasonably short. The latter condition increases the threshold magnetic field, particularly for large particles. However, for all studied mineral systems (hematite, siderite, goethite) the flocculation magnetic induction is in the range of industrially feasible magnetic fields (0.1-3 T), being higher for larger and less magnetic particles, and lower for fine and more magnetic minerals. The industrial application of magnetic flocculation in beneficiation of iron ores is outlined.
