Maria Coal Pyrolysis Studied by Fourier Transform Infrared and Mössbauer Spectroscopy

Abstract

Maria coal sample from Teruel, Spain, and its derivatives, the carbonized material of Maria at 600 ı C in an argon atmosphere, and the Maria coal ash produced at 850 ı C in air, have been mainly characterized by Fourier transform infrared and Mössbauer spectroscopy. The ultimate chemical and sulfur analysis, as well as the calorific values, are given. From the analysis of both chemical and Fourier transform infrared, the coal sample was identified as sub-bituminous coal with a high content of mineral matter, mainly kaolinite, which is altered during pyrolysis due to the loss of hydroxyl groups. On the other hand, the room temperature Mössbauer spectrum of the starting coal sample showed the presence of Fe 2C in pyrite and Fe 3C in jarosite. Further, the Mössbauer spectra of Maria samples (char and ash) showed, respectively, the presence of pyrrhotite (Fe 0:881 S) and hematite (Fe 2 O 3 ). However, the chemical changes in jarosite after pyrolysis was not relevant. The structure of pyrrhotite as obtained from its average magnetic field is discussed.