The present invention provides an apparatus for inducing magnetism in a flowstream of an at least partially magnetizable particulate feed material suspended in a liquid, the apparatus including: a treatment chamber having an inlet and an outlet through which the flowstream respectively enters and exits the chamber; and a magnetic source able to be selectively activated with respect to the treatment chamber, such that, when activated, the magnetic source induces magnetism in at least some of the particulate feed material located in the chamber. This allows the introduction of a high gradient magnetic field to effectively magnetize both the weakly and strongly magnetic particulates for subsequent removal by setting or other techniques. When the magnetic source is deactivated, the flow stream of feed material dissipates the deposits of magnetized material from around the source to reduce the possibility of any flow restrictions and maintain the effectiveness of magnets.