TESTING OF PYROMAG TM 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 PyroMag TM 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 PyroMag TM 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
PyroMag TM , Hot Magnetic Separation, Curie point, Direct Reduced Iron