High gradient magnetic separation in coal desulfurization

High Gradient Magnetic Separation (HGMS) has been successfully applied to the removal of pyrite from water slurries of raw coal in bench scale tests in several laboratories. Dry processing is more difficult but some advances have been reported. Coal-methanol slurries offer promise. HGMS has also been successful in filtering out particulate inorganic sulfur from liquefied solvent refined coal. The separation process is critically dependent on the thermomagnetic properties of the iron sulfides.