On the characterisation of carbon black from tire pyrolysis

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.