Characterization of solid particles with different particle sizes in high-temperature coal tar pitch

High-temperature coal tar pitch (HCTP) serves as a crucial precursor for high-quality carbon materials, while solid particle (SP) characteristics significantly influence the properties of the pitch. This study explores the compositional differences of SPs across various sizes to facilitate their effective separation. We employed ultrasonic graded centrifugation to isolate seven SP types of different sizes and analyzed their properties using SEM, SEM-EDS plane scanning, laser particle size analysis (LPSA), organic element analysis (EA), FT-IR, ICP-MS, and XRD. Our results reveal distinct variations in the SP distribution by particle size. As the particle size decreases, the proportion of particles in the 1-100 mu m range decreases, while ultrafine particles (0.01-0.1 mu m) become more prevalent. The carbon content in SPs initially increases and then decreases with smaller particle sizes, reaching a peak in medium-sized particles. Non-carbon impurities such as Si, S, Zn, Pb, Ca, Fe, and inorganic ash are concentrated in larger particles (SP1-SP2) and smaller particles (SP6-SP7). Notable inorganic compounds like PbS, ZnS, and FeS are found across all sizes, whereas SiO2 and CaCO3 are restricted to larger particles (SP1-SP2). Furthermore, smaller particles exhibit greater specific surface areas and pore volumes.