Recovery of Metallic Materials from Printed Wiring Boards by Green Pyrolysis Process

  • Alex LUYIMA Missouri University of Science and Technology
  • Lifeng ZHANG University of Science and Technology
  • Jaan KERS Tallinn University of Technology
  • Viktor LAURMAA Tallinn University of Technology
Keywords: WEEE, PWB, mechanical recycling, green pyrolysis, recovery of metals


Currently, the main options for the treatment of electronic waste are involved in reuse, remanufacturing, and recycling, as well as incineration and land filling. Recycling of e-waste can be broadly divided into three major steps: (a) disassembly: selectively disassembly, targeting on singling out hazardous or valuable components for special treatment, is an indispensable process in recycling of e-waste; (b) upgrading: using mechanical processing and/or metallurgical processing to up-grade desirable materials content, i.e. preparing materials for refining process; (c) refining: in the last step, recovered materials are retreated or purified by using chemical (metallurgical) processing so as to be acceptable for their original usage.
To investigate an environmentally friendly process to recycle PWBs, the milled PWB powder samples with and without additives were pyrolyzed. Liquid, gas and solid products were achieved with different conversion fraction. PWB powders were pyrolyzed and in a thermo-gravimetric analysis, differential thermal analysis (TG/DTA) and exhausted gases were analyzed by mass spectrometer (MS). Analysis of the exhaust gases from the experiments using TG-DTA-MS showed that without CaCO3 additives poisonous gases such as C6H6 and HBr were produced which were adequately controlled if CaCO3 was added.