Graphite, Artificial

Abstract

Abstract The raw materials used in the production of manufactured carbon and graphite largely control the ultimate properties and practical applications of the final product. This dependence is related to the chemical and physical nature of the carbonization and graphitization processes. Essentially any organic material can be thermally transformed to carbon. The carbonization process through the elimination of heteroatoms and substituent hydrogen converts the organic precursor into a carbon polymer. This polymer consists of aromatic carbons arranged in large polynuclear aromatic ring systems. With continued heat treatment, this carbon is transformed to a more or less ordered three‐dimensional framework approaching the structure of graphite. Differences in the final material depend on the ease and extent of completion of these overall chemical and physical ordering processes. Filler materials include petroleum coke, coal‐tar pitch coke, natural graphite, carbon blacks and anthracite. Carbon articles are made by mixing a controlled size distribution of coke filler particles with a binder such as coal‐tar or petroleum pitch. In addition to the primary ingredients, the fillers and binders, minor amounts of other materials are added at various steps in the carbon and graphite manufacturing process. They can play an important role in determining the quality of the final product. Light extrusion oils and lubricants, are often added to the mix to improve the extrusion rates and structure of the extruded products. Chemical inhibitors are introduced to reduce the detrimental effects of sulfur in high sulfur cokes. Nearly all coke utilized in carbon manufacture is calcined. Calcination consists of heating raw coke to remove volatiles and to shrink the coke to produce a strong, dense particle.