MOSSBAUER ANALYSIS OF THE MICROWAVE DESULFURIZATION PROCESS OF RAW COAL

Fe-57 Mossbauer spectroscopy was used to study the evolution of pyrite inherent in raw coal during microwave irradiation. The results for phase analyses shown that decomposing reaction of pyrite in coal, caused by microwave heating, FeS2 --> Fe1-xS --> FeS consecutively progresses to the right with increase of irradiation time. The whole process of microwave desulfurization of raw coal consists of the initiation, the promotion, and the saturation stages. Calculated results show that the inorganic desulfurization efficiencies from microwave treatment for irradiation time of 30-100 s are 5%-44%. The relatively higher desulfurization efficiencies are probably relative to the smaller particle size of both the pyrite and coal sample.