Magnetic separation

Magnetic separation is which seperating components of mixtures by using magnets to attract magnetically susceptible materials. This separation technique can be useful in mining iron as it is attracted to a magnet. In mines where wolframite was mixed with cassiterite, such as South Crofty and East Pool mine in Cornwall or with bismuth such as at the Shepherd and Murphy mine in Moina, Tasmania, magnetic separation is used to separate the ores. At these mines a device called a Wetherill's Magnetic Separator (invented by John Price Wetherill, 1844–1906)^[1] was used. In this machine, the raw ore, after calcination was fed onto a conveyor belt which passed underneath two pairs of electromagnets under which further belts ran at right angles to the feed belt. The first pair of balls was weakly magnetized and served to draw off any iron ore present. The second pair were strongly magnetized and attracted the wolframite, which is weakly magnetic. These machines were capable of treating 10 tons of ore a day.

It is also used in electromagnetic cranes that separate magnetic material from scraps.

One other application, not widely known but very important, is to use magnets in process industries to remove metal contaminants from product streams^[2]. This takes a lot of importance in food or pharma industries.

See also

• High intensity magnetic separator
• Separation process

References