A major UK mineral processing company has installed two large Bullet Magnets to remove tramp ferrous metal from dry reclaimed kaolin.
After initial discussions, Bunting conducted controlled tests in the Redditch Centre-of-Excellence. The reclaimed kaolin had a broad particle size range, with 95% below 250 microns. Iron contamination was approximately 1000ppm (although it could peak at 2000ppm) and the client was aiming to reduce this to below 120ppm.
Controlled Laboratory Tests
The laboratory tests concluded that the flow characteristics of the material did not suit dry-process Magnetic Separators such as Drum Magnets and Rare Earth Roll Magnetic Separators. Previous project experience indicated that material with such a particle size distribution would normally be processed in a wet slurry state. However, due to the customer’s process and end market requirements, the material needed to be handled in a dry state.
The tests also identified that the contamination was ferromagnetic iron, which probably originated in the ball mills.
Recommending Bullet Magnets
Subsequently, Bunting’s application engineers thought laterally and proposed magnetic separation technology successfully used successfully in the flour industry.
Bullet Magnets feature a magnetic cone centralised in a housing that fits into pneumatic and gravity fed pipelines. High strength designs, using Rare Earth Magnets, produce magnetic fields strong enough to capture fine iron. Once captured, the iron is held on the surface of the magnetic cone until manually cleaned during scheduled maintenance.
For this kaolin application and to maximise iron separation, the two Bullet Magnets were positioned in series. Approximately 4tph of kaolin would be gravity fed via a screw conveyor through the two Bullet Magnets.
To suit the capacity, Bunting recommended two Model MM250RE Bullet Magnets, both fitted with PN16 flanges. Each one is 950mm long and weighs 145kg. The magnetic cone is centrally housed inside a non-magnetic stainless-steel body and mounted to a hinged door for easy access and cleaning.
In operation, kaolin flows under gravity down from the screw conveyor through the Bullet Magnet, with all the material travelling through the strong magnetic field. The ferromagnetic iron particles are attracted to the surface of the cone magnet and separated from the non-magnetic kaolin.
Bunting-Redditch (previously known as Master Magnets) is widely regarded as one of the world’s leading suppliers of magnetic separation solutions to mineral processing companies. The Centre-of-Excellence laboratory in Redditch has an extensive range of high intensity magnetic separators for cleansing minerals in both a dry and wet state.
For further information on our range of magnetic separation equipment designed for purifying ceramics and non-metallic minerals, or to arrange sample tests in our laboratory, please contact us on:
Email Gordon Kerr: GKerr@buntingmagnetics.com
Telephone: +44 (0) 1527 65858