Characteristics and chemical treatment of carbon black from waste tires pyrolysis

The aim of this paper is to develop tires cracking carbon black with low ash content. The thermal decomposition characteristics of tires were investigated by thermogravimetric analysis, and the effects of pyrolysis variables on the yield, ash content and structure of pyrolytic carbon black were discussed by the laboratory tube furnace. Aiming at the phenomenon of high ash content in pyrolytic carbon black, the effect of acid and alkali solvent treatment on ash removal rate and the surface structural properties of carbon black were investigated. The experimental results show that the decomposition temperature of waste tire is between 300 °C and 500 °C, the yield of pyrolysis carbon black is 38%, and the ash content of carbon black is 19%, and the pyrolysis temperature has a significant effect on the surface impurity structure of carbon black. The carbon black was further treated with acid/alkali to optimize its surface properties, and the experimental results showed that acid treatment is more conducive to ash removal than alkali treatment. Under optimal conditions, when the concentration of HF solvent is 2 mol/L and the treatment time is 180 min, the ash content of carbon black can be reduced to 6.36%. At the same time, acid treatment also increases the microstructure of carbon black surface. The research in this paper provides basic data support for the research of carbon black preparation of waste tires.