Properties and structure of different rank anthracites

The properties and structure of anthracitic coals through to meta-anthracites were examined using a variety of analytical methods. With increasing rank, the following increased as well: moisture content, carbon content, vitrinite reflectance, reflectance anisotropy, microhardness, real and apparent density, whereas volatile matter content, hydrogen content and calorific value decreased. Increasing rank effected an increase of the spatial ordering of organic matter of the anthracites, decrease of the interlayer distance, and increase in the crystallite dimensions. Also, the number of condensed aromatic rings in the basic structural unit of the anthracites, index of condensation and aromatisation and total surface area and pore volume increased. The differences in the properties and structures of the anthracitic coals and meta-anthracites are described.