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TESTING OF PYROMAGTM FOR ENERGY EFFICIENT HOT MAGNETIC SEPERATION
ABSTRACT
Conventionally, direct reduced iron (DRI) mixed with char from rotary furnace discharge is cooled down
before separating the char via magnetic separator. The DRI must then be reheated for further downstream
processing (i.e. smelting). Outotec has developed the PyroMagTM specifically to conserve thermal energy
during this separation process. DRI is cleaned by feeding hot particles directly after reduction onto a
rotating surface just above a stationary magnet assembly. This allows hot feeding of the clean DRI to the
downstream equipment which renders the entire process more energy efficient.
Continuous testing of the PyroMagTM was performed to verify design and separation. Because the use of
DRI/char was not practical for test use, the pilot plant testing was conducted using a magnetite/ sand
mixture heated up to and beyond the Curie temperature of magnetite. The separation was efficient for both
cold and hot processing with recoveries varying from 98.6% to 99.74%. As expected, the recoveries
decreased to as low as 83.99% as the temperature was increased beyond the curie temperature of magnetite
(585˚C). Long term separation was thermally efficient and sustainable.
KEYWORDS
PyroMagTM, Hot Magnetic Separation, Curie point, Direct Reduced Iron