Resumen de Rare earth magnets fill a void

José Marín Mateos-Aparicio , Bill Dudenhoefer

• There are only a few common types of rare earth magnets that are considered for circuit design for magnetic separators. Early rare earth magnets of commercial significance consisted of the first generation of sintered samarium-cobalt magnet alloys (SmCo 5 ). The energy produced from these magnets ranged up to 23 megagaussoersteds (MGOe), which provided the initial impetus to the field of high-energy permanent magnets.

  The evolution of high strength permanent rare earth magnets has led to the development of high intensity separators that operate virtually energy free. The rare earth roll, for example, generates magnetic field intensities up to 21,000 gauss and is effective in either concentrating or removing weakly magnetic minerals from a process stream. Another example is the rare earth drum at slightly lower field strength.

  The rare earth drum magnetic separator consists of a stationary, shaft-mounted magnetic circuit completely enclosed by a rotating drum. The magnetic circuit has segments of alternating rare earth magnets and steel pole pieces that span an arc of 120 degrees. The steel poles are induced and project a high-intensity, high-gradient magnetic field.