The Hydrophobic Character of Pretreated Coal Surfaces

partially replace oil and natural gas as fuel sources. Of all the coal-cleaning pmesses, flotation is one. of the most versatile. Carbon dioxide coal flotation is a new technology developed at the University of Utah.(l) Compared with conventional flotation, carbon dioxide flotation enhances the ash rejection and increases flotation recovery for coals of different rank with the exception of lignite. However, significant improvement of the hydrophobicity and flotability of lignite has been found after controlled thermal pretreatment.The potential for the production of superclean coal by carbon dioxide has been demonstrated in bench scale flotation experiments.@)