Upcycling and characterization of flash-pyrolytic carbon black recovered from end-of-life tires

This study presents the development of a flash pyrolysis process for recovering carbon black from end-of-life tires, emphasizing the efficient removal of surface-bound organic impurities. The influence of solid residence time on the physicochemical properties of the recovered carbon black (rCB) was investigated at pyrolysis temperatures of 500 °C, 600 °C, and 700 °C. Experiments were conducted in an entrained flow reactor using two feedstock types: granulated passenger car and truck tires. The resulting rCBs were extensively characterized and benchmarked against commercial-grade carbon blacks to evaluate their physical and chemical properties. For the tested tire granulates (particle size 0–800 µm), pyrolysis at 600–700 °C with residence times of approximately 6–12 s achieved the removal of more than 98 wt% of organic impurities. While inorganic constituents remain in the rCB, these can be addressed through post-treatment where necessary. The developed flash pyrolysis process provides a rapid and effective route for producing high-quality rCB with low organic impurity content, contributing to a viable pathway for sustainable material recovery from end-of-life tires.