Study of the Transference Rules for Bromine in Waste Printed Circuit Boards during Microwave-Induced Pyrolysis

Abstract

The production of waste printed circuit boards (WPCBs) has drawn increasing global concern, especially because the high bromine (Br) content (5-15%) places obstacles in the way of simple disposal techniques. Microwave-induced pyrolysis of WPCBs provides a promising way to dispose of these hazardous and resource-filled wastes. The transference rules for Br during microwave-induced pyrolysis have been investigated experimentally. It was found that the microwave energy could be used more efficiently to accelerate the heating rate and improve the final pyrolysis temperature by adding some activated carbon (AC) as microwave absorbents. The high temperature and rapid pyrolysis process promoted the yields of gaseous products and the decomposition of brominated compounds into hydrogen bromide and then benefited the capture of Br and the debromination of byproducts. The application of a calcium carbonate (CaCO3) layer overhead led to over 95% debromination of the liquid products and over 50% capture of the total Br. It can be concluded that the presented method is suitable for the control of Br transference in the recycling of WPCBs. This method can also be extended to the disposal of the electronic scraps.

Experimental study on the heating effects of microwave discharge caused by metals

“…10,[17][18][19][20] Our working group is just carrying out research on the recycling of electronic wastes through microwave processing and find that microwave-induced pyrolysis combined with a featured mechanical processing is a very efficient way to recycle these wastes. [21][22][23][24] In our studies, the organic compositions in electronic wastes can be recycled in the form of energy and the metals can be effectively recovered.…”

Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating

“…Our research group has studied the heating effects associated with microwave-metal discharges and found that the energy conversion ratio from electrical energy to heat can reach as high as 30% [28]. Based on the unique material characteristics of WPCBs and the discharge properties of metals, we have previously established that microwave-induced pyrolysis holds promise as a way to process WPCBs [26][27][28][29][30].…”

E -Waste: Characterization and Disposal through Solid State Route

“…It has been observed that because of the selective characteristic, the microwave induced pyrolysis may be applied in an energy efficient way for PCB waste heat treatment. Application of some strong microwave absorbers may expedite the pyrolysis process by rapid heating [20]. Current studies present the inter-comparison studies with respect to the PCB waste characterization using microwave and resistive heating in order to understand the nature of volatiles and residue obtained during the two different heating processes.…”