Hidetaka Suginobe

Improvement and control of the quality of binder pitch for graphite electrodes

Abstract Factors influencing the coke yield and the softening point (SP) of pitches were studied to ascertain procedures for the improvement and control of their quality. The coke yield of pitches from different tar sources is expressed as a linear function of the BI content. Pitches were prepared by distillation under constant operating conditions. The coke yields of pitches, determined by thermogravimetric analysis (TGA), increased with their benzene insoluble (BI) content, which is controlled by reflux heat treatment. Softening point increased with the nitrogen content as well as BI content. Therefore, increasing the BI content and decreasing the nitrogen content increases coke yield without any change in the softening point of binder pitches for graphite electrodes.