ASTM D5187 Standard Test Method for Determination of Crystallite Size (Lc) of Calcined Petroleum Coke by X-Ray Diffraction
4. Summary of Test Method
4.1 A packed sample pulverized to less than 75 µm is subjected to a monochromatic X-ray beam and rotated to produce a diffraction pattern under specific conditions. The location and shape of the peak with hkl = (002) at d = 3.35; Å is used to calculate the Lc by manual interpretation of the peak or by computer simulation.
5. Significance and Use
5.1 The crystallinity of petroleum coke, as reflected by the Lc value, is a general measure of quality affecting suitability for end use and is a function of the heat treatment.
5.2 The crystallite thickness is used to determine the extent of such heat treatment, for example, during calcination. The value of the Lc determined is not affected by coke microporosity or the presence of foreign, non-crystalline materials such as dedust oil.
