HGMS coal desulfurization with microwave magnetization enhancement

The performance of high-gradient magnetic separation (HGMS) in removing mineral pyrite from coal has been improved by increasing the pyrite's magnetization through selective microwave heating. Separations were carried out on conventional 2-T iron magnet separators and using a superconducting magnet capable of 15 T. A critical temperature for conversion of pyrite to ferrimagnetic monoclinic pyrrhotite was determined by vibrating-sample magnetometer measurements, also used to assess the conversion of pyrite in irradiated coal samples. Thermal analysis demonstrated that temperatures reached after heating were higher in the pyrite than in the coal. Pyrite-coal samples were separated using continuous axial separation and conventional wire-matrix HGMS.<
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