The study of textural and structural transformations of carbonized anthracites

Specific physical and chemical properties of anthracites may be explained by the differences in chemical structure of basic structural units (BSUs) and in various spatial arrangements of BSUs, that is, the texture. The structure and the texture of anthracites correspond with their optical properties. Thermal treatment causes the changes in the structure of BSUs and rearrangement of the texture of anthracites. The character of structural and textural transformation could be determined based on the reflectance values of anthracites. s anthracites were thermally treated to the temperature of 1800 °C. Maximum (Rmax) and minimum (Rmin) reflectance values were measured and reflectance indicatrix parameters (Rev, Rst and Ram) were calculated for initial and heated samples. found that Rmax, Rmin and Rev values increase together with the temperature up to 1200–1400 °C. In higher temperatures, they start to decrease, while Ram parameter depending on anisotropy of the texture still increases to the final temperature of 1800 °C. That indicates gradual and soft transformation of the structure and the texture of anthracites up to the temperature 1200–1400 °C (arrangement of turbostratic structure) and some disturbances in textural order before the stage of graphitization.