SEM and reflected light petrography: A case study on natural cokes from seam XIV, Jharia coalfield, India

SEM photographs revealed some textural features of natural coke, which remained unexposed in optical microscopy. This may be due to the use of unpolished samples and greater depth of focus achieved by SEM. The features which were studied through these two microscopy methods are characterization of carbonized matrix, mosaics, flow textures, micro, meso and macropores and cracks formed due to escape of volatiles including properties of mineral matter or their altered products (glassy matrix). The different washability fractions of Burragarh natural coke have shown that there is gradual decrease of reactive macerals and increase of anisotropic mosaics, flow textures and deposited carbons up to specific gravity of 1.70. The approach thus enabled a combined maceral-mineral analysis, which bears good implications on academic and industrial use of natural cokes.