Explaining Magnetic Separation

Rotary Magnetic Separators, such as the Bunting Drum Magnet and Magnetic Separation Pulley, are designed with a specific type of magnetic field.  The type of magnetic field has to be considered when looking at any application and when deciding which design will achieve a customer’s separation objective.

So what is an Axial or Radial Magnetic Field and why is it so important?

Axial Magnetic Field

Axial Magnetic Field Bunting Magnetics- Figure 1 – Axial Magnetic Field

This is when the magnetic field stretches across the width of the rotary Magnetic Separator.  Magnetically susceptible material entering into the field is attracted to the point of highest magnetic intensity (the pole) but is then dragged through an area of weaker field (between the poles) and onto another pole by the motion of the conveyor or drum.

This type of magnetic field is ideal when there could be a high level of entrapped non-magnetic material captured by the Magnetic Separator.  The motion of moving between the poles results in non-magnetic material being released as the magnetic item ‘tumbles’ in the field.  However, with this type of magnetic field there can be a reduced separation performance.

Radial Magnetic Field

Radial Magnetic Field Bunting MagneticsFigure 2 – Radial Magnetic Field

The Radial Magnetic Field has poles running in the same direction as the rotation of the conveyor or drum and with the flow of the material.  Magnetically susceptible material is attracted to the points of highest magnetic intensity (the poles) and held until it is dragged out of the magnetic field underneath the conveyor or Drum.

This type of magnetic field is ideal when the maximum level of separation is required, but there can be some carryover of non-magnetic material.  The fact that the captured magnetics always remain on the pole of highest magnetic intensity means that they are far more likely to be removed and, therefore, the radial design provides the best level of separation.

These types of Magnetic Fields are used in Magnetic Separators such as Magnetic Drums and Magnetic Pulleys.

For further details on the Bunting range of Metal Separation Equipment, please contact our technical sales team on: