ZnO and SiO2 Recovery from Upgraded of Pyrolytic Carbon Black by Improved Solid-Liquid Extraction Method

Abstract

Pyrolytic fuel and pyrolytic carbon black are obtained as two major products from the pyrolysis of scrap tires. Pyrolytic carbon black, which contains high ash and carbonaceous residues, cannot be used like commercial carbon blacks in polymer industry. In this study, not only ash removal but also carbonaceous residues were extracted with solvent to obtain high grade pyrolytic carbon black, which is close to commercial carbon black. Extraction efficiency and surface activity were significantly improved by adding oxidizing agents as well as wetting and dispersive, chelating and complexing additives in the acid stage. More sulfur and SiO₂ were removed with the surfactant added in the basic stage. The properties of refined pyrolytic carbon black reached levels close to commercial carbon black N330. The zinc-rich metal solution obtained in the acidic method contains micro- and macro-nutrients, which are important fertilizers for plants. In addition, SiO₂ obtained in the basic phase is a good filler in polymer industry.