OIL AGGREGATED BEHAVIOR FOR COAL RECOVERY AND COMBUSTION CHARACTERISTICS OF THEIR AGGREGATES FROM DIFFERENT GRADE COALS

Large amounts of waste fi ne coals are very diffi cult to be treated due to the presence of ash and inorganic sulphur compounds. In order to use waste fi ne coal effi ciently, a retrieval technique is necessary for the recov-ery of combustible contents of coal from fi ne waste coals. Nowadays, a fl otation process has been used for the treatment, but it is impractical for developing countries due to its higher costs. Therefore, oil agglomera-tion process has been used to deal with these problems. In this study, the factors affecting the coal cleaning effi ciency of the oil agglomeration process were investigated with the element contents and chemical structure of three different grade coals. Chemical contents in three different grade coals were determined by proximate and ultimate analyses and the differences in chemical structure of carbonaceous contents of different grade coals were investigated by a Fourier transform-infrared spectrometry. In free coals or their mixed samples, the ratio of ash and carbonaceous contents were maintained to make it homogeneous. From the results of oil agglomeration experiments, it was concluded that the characteristics of agglomerate and the coal cleaning effi ciency of oil agglomeration were not only infl uenced by the type of oils but also by the oxygen contents and the aromatic and aliphatic chemical structures in different grade coals. The oxygenic functional groups of carbonaceous contents in coal samples prevented oil from attaching the carbonaceous surface and form th