Preparation of mesocarbon microbeads from coal tar

Mesocarbon microbeads (MCMB) was prepared from coal tars with various primary pyridine insoluble fraction (PI) contents from 0 to 3.7 wt %, through heat treatment at 430–480°C for different time under autoginious pressure. The heat treated coal tars were filtered under 150°C and the residue was rinsed with pyridine. MCMB was obtained as the pyridine insoluble fraction. Both yield and diameter of MCMB increased with the increasing of reaction temperature and holding time. It was found that primary PI also had strong influence on the formation of MCMB, which restricting coalescence between mesophase spheres by sticking on the surface of mesophase spheres or dispersing in the matrix. Low temperature, short reaction time and high PI content resulted in the MCMB with small diameter and narrow size distribution. Carbon block with 1.75 g/cm3 density could be easily obtained from the MCMB after molded under 100 MPa and carbonized at 1000°C.