Mineral Separation with Rare Earth Magnets
New earth magnets based on the concept of superconductivity have opened new possibilities in the field of magnetic separation. All minerals are somehow influenced by the magnetic field, although in few cases the effect is exceedingly small. Paramagnetic mineral and even so ferromagnetic minerals are strongly attracted along the lines of the magnetic force. This property is utilized to bring out mineral separation through high intensity magnetic or electromagnetic separators.
Introduction of new magnet technology, incorporating one or two rare earth alloys has far changed the scenario of magnetic separation. It has successfully superseded the onventional electromagnetic high-intensity magnetic separators. One of the examples of this technology is Rapid Mag Roll Magnetic Separator, which has been successfully installed for various mineral processing applications.
Specially engineered design configurations are used to produce high-intensity magnetic fields, while "superconducting" phenomena at extremely lower temperature results in generation of stronger magnetic field. These high-intensity field allows easy removal of contaminates with even feeble magnetic property. The technology is widely used for processing of minerals such as glass sand, talc and kaolin.
The function of the earth alloy magnetic separators
are influenced by two variables; Magnetic Field Intensity and Magnetic Field Gradient. These factors are primarily responsible for the separation response. The intensity of magnetic field means the number of lines of flux passing through a unit area, while magnetic field refers to the rate of change of magnetic field, or convergences of the magnetic flux. A high gradient is induced at a point where the magnetic lines converges. Magnetic particles or minerals under
the influence of the magnetic field will migrate to the region of highest flux density. The migration of the particles will occur at the tip of the point or ridge, and this forms the basic principle of
Precisely, magnetic intensity holds the particles while magnetic field gradient moves the particle. Magnetic force acting on a particle is the product of the magnetic field intensity and magnetic field gradient. To obtain maximum magnetic field intensity magnetic field intensity and field gradient are both amplified to the highest.
Earth Magnets and Drum Separators
The drum separators consist of a hollow cylindrical rotating drum manufactured from stainless steel or similar non-magnetic material with a permanent earth magnets
mounted in a fixed (adjustable) position within the drum. These separators are available in different models, depending on the type of material to be processed.
For granular material, the slurry is delivered to the top of the drum, either directly by feeder or carried over it by a conveyor. In such configurations the drum acts as a head pulley. Magnet is located at the core of the drum, so that non magnetic material can follow a natural trajectory part and are automatically ejected off the drum, while the magnetic impurities are held against the drum surface. These impurities are carried off and discharged.
Wet processing involves the immersion of lower portion of the drum in the bath of mineral-carrying slurry. The slurry is fed into the bath, which moves around the drum and overflows the weir. Magnets are placed with the immersed portion of the drum. The rotation of the drum stirs the mineral content, and the magnetic particles flow around the drum. Thus the magnetic particles are attracted to the inner magnet, which carries the magnetic particles in one direction. Eventually with the influence of the magnetic field, these contaminants fall off into a discharge chute. The non magnetic particles are carried by the slurry flow which finally spill over the weir.