The effect of composition change and allocation in raw material on the carbonaceous structural evolution during calcination process

• Furfural refining could enrich Tri-Ar and Tetra-Ar to a certain extent. • Blending key components for co-carbonization improved orderly layer stacking. • Calcination strengthened the structural characteristics of green coke stage. To investigate the effect of calcination process on the characteristics of different carbonaceous structures, decant oil (DO) and low-temperature coal tar (LCT) were selected as materials to refine and blend to prepare the green cokes with different microstructures, and the influence of calcination on the structural evolution of green cokes with different orientation and planarity was studied. It is concluded that the nitrogen content of calcined needle coke decreased to a relatively low value at the calcination temperature of 1300℃ and the removal of QI decreased the sulfur content in calcined cokes. Calcination process would further promote the accumulation of aromatic lamellae on the original basis. The abundant QI in LCT led to the formation of mosaic structures in green coke stage and calcination aggravated the poor planarity of aromatic sheets of mosaic texture. The refining process and blend of raw materials significantly enhanced the proportion of key components and calcination improved the extendability and planarity of graphitic aromatic sheets with the increase of Tri-Ar and Tetra-Ar. In addition, calcination further optimized the aromatic lamellae of acicular domain texture with good planarity and structural orientation, and DO-CNC obtained the highest stacking parameters (L c = 3.55 nm; N = 11.30; d 002 = 3.445 Å).