Apparatus and method for magnetising materials

An apparatus arranged for inducing magnetism in a flowstream of at least partially magnetisable, dry particulate feed material, in order to effect a subsequent particle classification thereof, in use the flowstream being fed into a dry separation stage which is located proximal to said magnetic induction apparatus, the apparatus comprising:

• a treatment chamber with an inlet and an outlet, through which the flowstream respectively enters and exits the treatment chamber;
• and
• a plurality of spaced-apart magnetic sources located adjacent to, and moveably displaceable in the same direction along the length of both an upper and a lower side region of the treatment chamber, such that, during said movement, a respective magnetic source from each of the upper and lower side regions forms a pair of magnetic sources which are aligned in opposing relation to one another, and laterally spatially positioned apart with respect to one another, in use each of said pairs of magnetic sources generating a localised magnetic induction field zone;
• and
• said upper side region of the treatment chamber being defined by at least one of a moveable first surface element which is configured in use to move over a face of said spaced-apart magnetic sources which are located thereabove, and said lower side region of the treatment chamber being defined by at least one of a moveable second surface element which is configured in use to move over a face of the spaced-apart magnetic sources which are located therebelow;
• wherein during operation of the apparatus:
• the second surface element transports the flowstream of dry particulates into the treatment chamber via the inlet;
• and
• once inside the treatment chamber, the relative rate of motion of the first surface element with respect to the magnetic sources at the upper side region of the chamber is greater than the relative rate of motion of the second surface element with respect to the magnetic sources at the lower side region of the chamber, thereby creating a region of air-particle fluidisation and agitation within the treatment chamber due to physical separation of the particulate feed material from the second surface element;
• and
• the combined effect of air-particle fluidisation and agitation during exposure to said localised magnetic induction field zones generated by said respective pairs of magnetic sources, results in a physical classification of said particulates, based upon their susceptibility to magnetic induction, such that:
• a feed material fraction with high susceptibility to magnetisation is retained at the first surface element due to a preferential attraction to the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber;
• a feed material fraction with medium susceptibility to magnetisation is repelled by the pairs of spaced-apart magnetic sources which are located at both the upper and lower side regions of the treatment chamber, ultimately is retained at the second surface element in the regions of low magnetic intensity located between the pairs of spaced-apart magnetic sources in the treatment chamber;
• and
• a feed material fraction with low susceptibility to magnetisation is ultimately retained at the second surface element in a region adjacent the spaced-apart magnetic sources which are located at the lower side region of the treatment chamber to which it is attracted, as well as due to repulsion by the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber.

A method for inducing magnetism in a flowstream of at least partially magnetisable, dry particulate feed material, and effecting a subsequent particle classification thereof using a dry separation apparatus which is located proximal to a magnetic induction apparatus, wherein said apparatus comprises:

• a treatment chamber with an inlet and an outlet, through which said flowstream respectively enters and exits the treatment chamber in use;
• and
• a plurality of spaced-apart magnetic sources located adjacent to, and moveably displaceable in the same direction along the length of, both an upper and a lower side region of the treatment chamber, arranged in use so that when pairs of laterally separated magnetic sources, one from each of said upper and lower side regions, are located in opposing facing alignment with one another, a localised magnetic induction field zone is generated therebetween;
• and
• a first surface element which, in use, moves over faces of the plurality of spaced-apart magnetic sources located at the upper side region, and a second surface element which, in use, moves over faces of the plurality of spaced-apart magnetic sources located at the lower side region;
• the method comprising the steps of:
• following a transfer of particulate feed material onto the second surface element, causing said second surface element to transport said flowstream of particulate feed material into the treatment chamber via the inlet;
• and
• setting the rates of motion of
• (a) the first surface element
• (b) the magnetic sources at the upper side region of the chamber,
• (c) the second surface element, and
• (d) the magnetic sources at the lower side region of the chamber,
• so that the relative rate of (a) to (b) is greater than the relative rate of (c) to (d), thereby creating region(s) of air-particle fluidisation and agitation within the treatment chamber, due to physical separation of the particulate feed material from the second surface element;
• wherein the combined effect of air-particle fluidisation and agitation during exposure to said localised magnetic induction field zones generated by said respective pairs of magnetic sources, results in a physical classification of said particulates, based upon their susceptibility to magnetic induction, such that:
• a feed material fraction with high susceptibility to magnetisation is retained at the first surface element due to a preferential attraction to the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber;
• a feed material fraction with medium susceptibility to magnetisation is repelled by the pairs of spaced-apart magnetic sources which are located at both the upper and lower side regions of the treatment chamber, and ultimately is retained at the second surface element in a region of low magnetic intensity located between the pairs of spaced-apart magnetic sources in the treatment chamber;
• and
• a feed material fraction with low susceptibility to magnetisation is ultimately retained at the second surface element in a region adjacent the spaced-apart magnetic sources which are located at the lower side region of the treatment chamber to which it is attracted, as well as due to its repulsion by the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber.