Changes in the petrographic composition of coal batch on crushing

Abstract

The influence of crushing on the maceral composition of coal is studied. The experimental data indicate not only redistribution of the petrographic microcomponents by size but also change in the maceral composition, depending on the intensity of grinding. With increase in the degree of crushing from 55.5 to 96.2%, the vitrinite content in the batch declines from 70 to 63%, while the total content of fusinized components increases from 29 to 35%. For coal with 50–80% vitrinite, which is less strong than coal with smaller vitrinite content, crushing is probably accompanied by disruption of the molecular interactions and rupture of the chemical bonds in the organic macromolecules. That leads to partial destruction of the brittle vitrinite structure, especially in the intermediate stages of metamorphism (R_o = 0.9–1.39%).