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Waste tires are also known as "black pollution", and pose significant risks to human health and ecosystems. The pyrolysis process can recover valuable products such as natural gas, oil, and pyrolysis carbon black (CBp), with CBp being the most important one. However, CBp from waste tires has a high degree of particle aggregation and low oil absorption value, making it difficult to further utilize. In this work, we propose a novel method to activate CBp by simulated fuel gas, which fully utilizes exhaust gas resources and enables the reuse of resources. The simulated fuel gas, composed of a mixture of N2 and CO2, was used to investigate the effects of activation temperature (700–1000 °C), activation time (2–5 h), flow rates (30–50 mL·min−1), and the content of CO2 in the simulated fuel gas (10%-90% (volume)) on increasing the specific surface area. The samples were analyzed using XRD, SEM, N2 adsorption/desorption, and Raman shift. The results indicate that the hybrid atoms and carbon atoms in CBp can absorb enough energy to open the closed pores, allowing the activator to fully react with CBp. This work demonstrates a feasible approach to improve the high value-added utilization of cracked carbon black. [ABSTRACT FROM AUTHOR]

The virgin CBp produced from scrap truck tires pyrolysis was analyzed both under N2 and under air flow with thermogravimetric analysis coupled with differential thermal analysis (TGA-DTA). Complementary information was derived from the two analysis. The rubber pyrolytic residues present on virgin CBp are better determined quantitatively by TGA-DTA under N2 flow. On the other hand, for the quantification of pure CBp and moreover of the ashes, the TGA-DTA under air flow is a necessary approach. It was also found that the rubber pyrolytic residues coating the virgin CBp surface can be determined quantitatively by a DSC scan under O2 flow up to 450 °C integrating the exothermal peak at about 340 °C and using as reference the thermo-oxidative enthalpy measured on a reference sample of natural rubber or selected model compounds. It is shown that the light pyrolysis process to clean CBp from the rubber pyrolytic deposits is completely satisfactory when conducted in a DSC scan under oxygen flow rather than under nitrogen flow. [ABSTRACT FROM AUTHOR]

A commercially available pyrolytic carbon black (CBp) produced from the pyrolysis of used tires was analysed by TGA-DTA showing that the effective carbon black content about 70% by weight, while about 14% are ashes and about 16% rubber pyrolysis residues adsorbed on the surface. GC-MS analysis of the latter fraction has permitted to identify at least 34 different molecules, some of them under the form of alkylated benzenes and alkylated naphthalenes and higher PAHs. Two simple procedures are shown to be effective in the quantitative determination of zinc and sulphur content of CBp. The surface area of CBp should be evaluated with both the ASTM D6559-19 and the ASTM D4607 test methods. CBp was also analysed with SEM-EDX and with FT-IR and Raman Spectroscopy. The latter spectroscopical technique was employed both on pristine and thermally annealed CBp, demonstrating that also CBp is a partially graphitizable carbon black similar to the N774 ASTM grade. [ABSTRACT FROM AUTHOR]