Comparative Study on Structural Parameters of Graphitized Coal-Petroleum Co-cokes and Pennsylvania Anthracites, with Implications for Their Use

Nuclear-grade graphite samples, anisotropic commercial graphite, graphitized co-cokes, and anthracites were characterized using X-ray diffraction, Raman spectroscopy, and temperature-programmed oxidation. Through evaluation of relationships between structural parameters, it was observed there is better likelihood to obtain isotropic or near-isotropic graphite from co-cokes than anthracites. The addition of coal to petroleum feed, i.e., vacuum resid or decant oil, reduces the concentration of large isochromatic units in a co-coke structure, thus leading to a graphitic structure that lacks anisotropic character upon graphitization of the co-coke. The structural characteristics of graphitized anthracites showed more similarities to anisotropic commercial graphite, in comparison to graphitized co-cokes. It was also found that coking a vacuum resid/coal blend offers better potential for producing an isotropic or near-isotropic graphite than the coking of a decant oil/coal blend. Increasing the co-coking temperature from 465 to 500 degrees C appeared to favor obtaining isotropic or near-isotropic graphite upon graphitization.