Carbonization behavior of coal-tar pitch modified with lignin/silica hybrid and optical texture of resultant semi-cokes

Coal-tar pitch was modified with a lignin/silica hybrid (LSH) from rice husk, and carbonization behavior of the pitch-LSH mixtures and optical texture of resultant semi-cokes were studied in this paper. The carbonization behavior was characterized using TGA, FTIR, SEM and EDS. In addition, the optical texture of resultant semi-cokes was characterized by polarized-light microscopy. Results show that the LSH addition has great effect on the carbonization behavior of the pitch-LSH mixtures and the optical texture of resultant semi-cokes. The pitch-LSH mixtures have better thermal stability than coal-tar pitch, as indicated by that the initial weight loss temperature and carbonization yield of the pitch-LSH mixtures increase with increasing LSH content. There are more condensed polynuclear structures with high aromaticity in the resultant semi-cokes with increasing pyrolysis temperature. However, the LSH addition deteriorates the optical texture of resultant semi-cokes varying from coarse-grained mosaics to fine-grained mosaics. Furthermore, there exist a great many silica particles with size of less than 3 μm uniformly distributed in the pyrolysis product of the pitch-LSH mixture.