Magnetic separators

A magnetic separator comprising:

• a. a magnetically impermeable rotor mounted on a vertically oriented shaft and having at least one annulus constituting or formed on its periphery and defined by spaced-apart walls, the walls being formed from a material having non-magnetic characteristics, and the at least one annulus being disposed about the axis of rotation of the rotor,
• b. a number of spacer bars of a magnetically permeable material extending in a radial direction between the walls of the annulus successive spacer bars together with the annulus walls defining through passages into which magnetic particles in a liquid slurry may be fed to pass in a direction substantially parallel to the axis of the rotor said spacer bars being of laminated construction with the planes of the laminations extending in the direction of rotation of the spacer bars,
• c. a number of magnetic pole pieces surrounding the rotor and having their magnetic axes disposed radially with respect to the rotor said pole pieces providing successive radial magnetic pole regions of opposite polarity around the rotor whereby a magnetic field of maximum intensity is induced in the spacer bars intermediate successive ones of the magnetic pole regions,
• d. means for feeding the slurry into the top ends of said passages adjacent the magnetic pole regions,
• e. a plurality of first means above the respective pole regions for delivering a washing fluid into the top ends of said passages for washing magnetic particles from within the passages,
• f. a plurality of second means for delivering a washing fluid into the top ends of said passages for washing non-magnetic particles from within the passages, said second means being disposed above top end of said annulus and circumferentially between said first means, and, separate means for collection of magnetic and non-magnetic particles which are washed from the bottom ends of said passages.