Plate magnets or magnetic plates are cost-effective, robust magnets. They are suitable for filtering metal particles out of free-falling product streams or products on a conveyor belt with relatively little Fe contamination. Permanent magnetic plates can easily be built into existing installations. Used in this way, plate magnets serve to protect processing machines in a reliable, economical manner, which prevents interruption of production processes. The effectiveness of plate magnets varies from 70 to 90% deferrization. If an even purer product is desired, multiple magnets or magnet systems can be installed in series.