Magnetic Separation: Industrial and Lab Scale Applications

(Saikia 2003, Iannicelli 2000, Gerber 1983 p132, China Clay Producers
Association)
Naturally colored due to the iron containing micas, tourmaline, pyrite, anatase and rutile,
kaolin needs to be magnetically cleaned before used in paper or porcelain (Oder 1973,
Oder 1976 IEEE, Gerber 1983 p132, Lofthouse 1981). Since the first magnetic removal
of impurities by J. M. Huber Corp. in 1969, kaolin is processed for coating quality
throughout the world with continuous high gradient magnetic separator (Figure 2).
Competing with the leaching process, where chemical resistance of impurities limits
usage, HGMS handles 75% of world production (Oder 1976). A typical plant would
have an HGMS with a filter diameter of about 2 m and capacity up to 20 tons/h
(Hirschbein 1982). Figure 3 shows kaolin mineral before and after the decolorization
process.