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pp.347-356
This research was designed to elucidate the pyrolysis reaction characteristics of waste epoxy printed circuit board (e- PCB). The samples were pulverized after removing coppers by gravity separator. Non-isothermal pyrolysis kinetic results by Thermogravimetric Analyzer (TGA) displayed two apparent reaction regions : 1) fast degradation zone and 2) slow degradation zone. According to batch experiments, solid by-products are responsible for about 78%, while liquid and gas by-products, respectively, represent 13 and 9%. The high content of solid by-products is ascribed to that of SiO2 that is a major components of e-PCB. Liquid by-products exhibit high content of oxygen (19%) and contain the nitrogen of about 1%. It is recommended that gas, liquid, and solid by-products of waste e-PCB would not be applied directly as fuels. Instead, pyrolysis of e-PCB would be applied to recover valuable rare metals and coppers from solid by-products. Application of liquid by-products is likely to be limited due to the presence of brominated oils precursor in liquid byproducts. It is necessary to develop upgrading methods for improving the quality of liquid by-products of waste e-PCB. According to kinetic analysis and product characterization, pyrolysis reaction model of waste e-PCB is accounted for by a series reaction with two independent reactions of two resins: brominated epoxy resins and non-brominated epoxy resins. At the first-stage, two resins are independently decomposed to generate thermally stable intermediates followed by slow degradation of the intermediates to be converted into char.
