Determination of organic sulphur in raw and chemically cleaned coals by scanning electron microscopy and energy dispersive X-ray spectrometry

Scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS) is a useful method to evaluate chemical cleaning processes and to obtain values of the organic sulphur remaining in cleaned coals. Pressed pellets can be used when the cleaning process has made the coal too heterogeneous to analyse by the conventional epoxy mounting method. The SEM-EDS analysis time is the same for both methods, whereas the preparation of pellets is much easier than that of epoxy mounts. The overall analysis time should therefore be decreased by using the pellet technique.