Low temperature ashing of coal was examined to prepare the first born ash materials which may distinguish the minerals present in coal and produced by ashing. The minerals were analyzed by SEM-EDX to distinguish the ashes in the Drayton (DR), Blair Athol (BA) and Nanton (NN) coals. The thermal behaviors of ashes were also investigated with or without CaCO_3. The large ash grains (<10μm) were found to carry much the same compositions and appearances. Major differences in composition were found in fine ash (<1μm): Si>Al for DR, Al>Si for BA and Al>Si>Ti for NN. Heating to 1000℃ appears to cause the adhesion of fine grains to similar extents regardless of the coals. Limestone accelerated the adhere of particles through fusion and deformation, giving spherical fine ashes from DR and BA. Ash from NN appears resistive to change the morphology even in the presence of limestone, suggesting its low reactivity.
