Characterization of Microstructure Changes of Pyrolytic CCCP and Their Effect on Carbon Reactivity by Industrial CT, Mercury Intrusion Porosimetry, and SEM

The microstructure changes of pyrolytic CaO-containing carbon pelletsCaO-containing carbon pellets (CCCP) directly determine their ability to produce calcium carbide (CaC2) in an electric arc furnace. Therefore, the microstructure changes, especially the pore structure changes of CCCP at different pyrolysis temperaturesTemperature were characterized by industrial CTIndustrial CT, mercury intrusion porosimetryMercury intrusion porosimetry (MIP), and SEMScanning electronic microscope (SEM) from different scales. The reactivity of carbon in pyrolytic CCCP was tested. The relationship between pore structure change and carbon reactivityCarbon reactivity was established. The results showed that industrial CTIndustrial CT could show the overall pore distribution of CCCP in a three-dimensional way; MIP was more accurate for the statistics of the proportion of pores with different pore diameters, and SEMScanning electronic microscope (SEM) was more intuitive for the local microstructure analysis of CCCP. As temperatureTemperature increased from 450 to 750 °C, the porosityPorosity and average pore diameter of CCCP increased, and decreased over 750 °C. Meanwhile, the reactivity of carbon in CCCPCaO-containing carbon pellets pyrolyzed at 850 °C was the highest.