The effect of mechanical vibration on the structure of needle coke prepared from a modified coal tar pitch

A medium coal-tar pitch was refined to remove the quinoline insoluble fraction and then modified with triacetate glycerol at 230℃ for 5 h. The modified pitch was carbonized at 550℃ under mechanical vibration. The effect of the mechanical vibration on microstructure of the coke was investigated by TG, FT-IR, XRD, SEM and polarized microscopy. Results indicate that the thermal stability and carbonization yield of the pitch increase and its aromatic/aliphatic hydrogen ratio is decreased by the modification. The mechanical vibration facilitates the coalescence of mesophase microbeads and the formation of a linear fiber structure during carbonization. The Lc of the semi-coke increases, d₀₀₂ decreases and the fiber structure remains after calcination at 1 300℃. A needle coke with high performance can be prepared by a combination of the modification and mechanical vibration.