Microstructural characteristics of toluene and quinoline-insolubles from coal–tar pitch and their cokes

The structural composition of coal–tar pitch used in the preparation of the special binder-pitch, was determined with special emphasis on the optical properties of the β-resins, as typical components necessary to obtain electrodes of best quality through the pyrogenetic processes of baking and graphitization. In addition to raw toluene- and quinoline-insolubles (TI, QI), the corresponding cokes were analysed to evaluate, by structural composition and microtexture, the behaviour of pitch fractions during carbonization. The results suggest the dependence of the texture development on the type of toluene- and quinoline-insolubles and β-resins during processing conditions, which influence the mesophase formation. An original and important result of the carbopetrographical study is represented by the identification and evaluation of β-resins in the coke texture.