Analysis of the Average Poly-Cyclic Aromatic Unit in a Metaanthracite Coal Using Conventional X-Ray Powder Diffraction and Intensity Separation Methods

Abstract

X-ray characterizations of coals and coal products have occurred for many years. Hirsch and Cartz measured the diffraction from several coals over the reciprocal space region from s = 0.12 Å-1 to 7.5 Å-1 where s = (4πλ) sine). In these studies, a 9 cm powder camera was used to study the high angle region, and a transmission type focussing camera equipped with a LiF monochromator was used for the low angle measurements. They reported that the height of the graphene peak (ca. 3.5 Å) measured for each coal is proportional to the % carbon in the coals. Hirsch also suggested that the ontyberem anthracite (94.1% carbon, 3.0% hydrogen, and 5.3% volatile matter with a specific gravity of 1.46) has a lamellar diameter of ca. 16 Å corresponding to an aromatic lamellae of ca. C87. For coals with lower carbon content, Hirsch proposed much smaller lamellae; C19 for a coal with 80% carbon, and C24 for a coal with 89% carbon.