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Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating
National Engineering Laboratory for Coal-fired Pollutants Emission Reduction, Energy and Power Engineering School, Shandong University, 17923 Jingshi Road, Jinan, Shandong 250061, China
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Received: 2 July 2012; in revised form: 8 August 2012 / Accepted: 24 August 2012 / Published: 31 August 2012
Abstract: This paper describes a kinetic study of the decomposition of waste printed circuit boards (WPCB) under conventional and microwave-induced pyrolysis conditions. We discuss the heating rates and the influence of the pyrolysis on the thermal decomposition kinetics of WPCB. We find that the thermal degradation of WPCB in a controlled conventional thermogravimetric analyzer (TGA) occurred in the temperature range of 300 °C–600 °C, where the main pyrolysis of organic matter takes place along with an expulsion of volumetric volatiles. The corresponding activation energy is decreased from 267 kJ/mol to 168 kJ/mol with increased heating rates from 20 °C/min to 50 °C/min. Similarly, the process of microwave-induced pyrolysis of WPCB material manifests in only one stage, judging by experiments with a microwave power of 700 W. Here, the activation energy is determined to be only 49 kJ/mol, much lower than that found in a conventional TGA subject to a similar heating rate. The low activation energy found in microwave-induced pyrolysis suggests that the adoption of microwave technology for the disposal of WPCB material and even for waste electronic and electrical equipment (WEEE) could be an attractive option.
Keywords: kinetic study; microwave-induced pyrolysis; waste printed circuit boards (WPCB); activation energy
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MDPI and ACS Style
Sun, J.; Wang, W.; Liu, Z.; Ma, Q.; Zhao, C.; Ma, C. Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating. Energies 2012, 5, 3295-3306.
Sun J, Wang W, Liu Z, Ma Q, Zhao C, Ma C. Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating. Energies. 2012; 5(9):3295-3306.
Sun, Jing; Wang, Wenlong; Liu, Zhen; Ma, Qingluan; Zhao, Chao; Ma, Chunyuan. 2012. "Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating." Energies 5, no. 9: 3295-3306.