Pyrolysis of Printed Circuit Boards

Abstract

Printed Circuit Board (PCB) is an essential co mponent of almost all electrical and electron ic equip ments. The rapid growth of the use of such equipments has contributed enormously to the generation of large quantity of waste PCBs. The WPCBs not only contain valuable metals but also a large variety of hazardous materials. Conventional treat ments of such WPCBs have their o wn limitations. By pyrolysis of WPCBs, it is not only possible to obtain the organic part of it as a fuel or useful chemical but can make further processing to recover metals much easier and efficient. In the present work, a kinetic study on the low temperature pyrolysis of WPCBs using a thermogravimet ric analyser has been attempted. The TG analysis was conducted in nitrogen and air at mospheres in the temperature range of 200-600℃ at a heating rate of 40℃ /min. The kinetic expressions for both the environments were determined and the activation energies were found to be 110.7 and 90.2 kJ/ mo l for n itrogen and air, respectively. The effect of thermal pre-t reatment on the subsequent copper leaching in nitric acid for untreated, pyrolysed and air-burned PCB was also studied. Copper recoveries fro m these samples were 30.4%, 92.5% and 96.2%, respectively indicating the importance of thermal pre-treat ment in leaching of the metal content.