Pitch coke structure and its transition into graphite: Influence of the separation process of quinoline-insoluble matter

Abstract

It has been established that the texture of pitch coke depends on the pre-carbonization treatment of the pitch and the separation of the primary quinoline-insoluble matter (OI). Scanning electron microscopy was used to examine the texture of fracture surfaces of pitch cokes prepared from the raw pitch and from pitches deprived of their QI fractions by quinoline extraction or filtration, three basic structures, lamellar, globular and composite, being determined. The arrangement of the lamellar structure is affected by the method of separation of QI and results in different graphitizable products. In pitch, filtered at 350 °C, the first symptoms of lamellar arrangement were already observed at heat treatment ∗ > 450 °C .