Carbon from Microwave Assisted Pyrolysis of Waste Tires

This paper presents a correlation between the experimental conditions of microwave assisted pyrolysis (MAP) of tires and some of the characteristics of the char obtained. MAP is a complementary or even an alternative methodology to recycle waste polymeric materials. This appealing methodology was employed in managing waste tires since they contain a high amount of microwave absorbing materials such as metal wires, metal oxides, and carbon, which quickly adsorb microwave radiations (MW) and turn them into heat. Carbons obtained from MAP of tire were characterized through chemical (ultimate analysis, iInfrared sSpectroscopy, Iion cCoupled pPlasma-Mmass Sspectroscopy), morphological (BET surface area, sScanning eElectron mMicroscopy), and X-Rray dDiffraction (XRD) analyses. MAP variables such as MW power and tire mass, did not strongly affect the properties of the samples. Chars contained large amount of amorphous carbon and inorganic compounds formed from additives employed in tires formulation. Hydrocarbons were present only in not-fully pyrolyzed samples. XRD analyses of crystalline phases showed a marked MW effect: Different crystalline ZnS forms, spharelite or wurtzite were present due correspondingly to the different amount of waste tires employed. The presence of these compounds suggested that tires were heated to a temperature higher than the usually accounted.