THE INHERENT HETEROGENEITY WITHIN THE VITRINITE MACERAL GROUP

Research has been directed towards the characterization of ultra-fine coal. Equipment and procedures have been developed which permit full reflectance characterization on vitrinite particles as small as 1.5 mum diameter using rotational polarization techniques. The application of this technology towards the evaluation of vitrinite macerals separated using density gradient centrifugation has provided insights into the inherent heterogeneity of the vitrinite maceral group. It is concluded that much of the scatter in reflectance values obtained for a given coal is due to the presence of remnant cell structure. This structure cannot only be observed through etching, but can be directly measured using reflectance. Density gradient centrifugation can be used to separate and concentrate these remanent structures in high volatile bituminous vitrinite, provided the sample has been crushed to 5 mum or less. Within this rank range there is a strong trend towards increased reflectance with increasing vitrinite density.