GB963746A - Method and apparatus for magnetic concentration of particulate material - Google Patents

Abstract

963,746. Magnetic separators. D. WESTON. Jan. 11, 1961 [Dec. 23, 1960], No. 1240/61. Heading B2J. Continuous separation of particulate material, such as lowgrade iron ore, of different magnetic susceptibilities is effected by feeding the material in an elongated shoot which is traversed continually by a series of longitudinally spaced magnets the opposite poles of which embrace the shoot so as to produce a magnetic flux across the entire cross-section thereof and magnetic gradients along the length thereof whereby the more strongly magnetic particles are concentrated and collected separately from the weaker particles. Figs. 5 and 6 show the shoot as a hollow non-magnetic ring 20 of rectangular cross-section which is twice as deep as it is wide, with a series of electromagnets 36 circumferentially spaced around the periphery of a wheel 38 mounted for rotation about the axis of the ring 20 so that the poles of the magnets lie close to the opposite sides respectively of the ring section. The shoot is supported on legs 21, 22 and material is fed into the shoot via a duct 27 to fall in a direction (counter-clockwise) opposite to the direction of movement of the magnets 36. In operation, the magnets adjacent the feed duct collect the more strongly magnetic particles and any which are not so collected are caught up by the succeeding magnets traversing the recovery path of the shoot, the tailings being exhausted by a fan or pump 31 from a receiving portion 28 at the lower end of the shoot. The magnetic concentrate is thus carried around the shoot and is collected at the lower portion 29 thereof which is blocked off from the portion 28. The energization of the magnets may be interrupted as they reach the top of the shoot to facilitate recovery of the concentrate, and baffles 34a, together with circumferentially spaced water inlets 32-35 may be provided in the shoot to clean and wash the concentrate. A fibre-glass paddle wheel may be rotated in the shoot portion 29 for positive discharge of the concentrate. The magnets 36 may be arranged either with like poles on the same side of the shoot or with their poles alternating around each side of the shoot. In an alternative arrangement, Fig. 11, the outer periphery of the shoot, together with the feed and water inlets and collecting portions may be supported to form a stationary cover 105 sealed to a circular channel 100 which is fixed to the poles of the magnets 112 for rotation therewith. In further arrangements, the shoot may be of inverted-U- form with the recovery path vertical, Fig. 2, or horizontal, Fig. 3, the magnets being carried on an endless chain 11. If desired, the magnets may be moved in the same direction as material feed rather than counter thereto. Magnetic field intensities up to 35,000 gauss may be used, and heat dissipating means may be associated with the magnets.