Self-catalytic pyrolysis thermodynamics of waste printed circuit boards with co-existing metals

Highlights

● The co-existing metals in WPCBs has positive catalytic influence in pyrolysis.

● Cu, Fe, Ni can promote reaction progress and reduce the apparent activation energy.

● Ni play better role in promoting WPCB pyrolysis reaction.

Abstract

Waste printed circuit boards (WPCBs) are generated increasingly recent years with the rapid replacement of electric and electronic products. Pyrolysis is considered to be a potential environmentally-friendly technology for recovering organic and metal resources from WPCBs. Thermogravimetric analysis and kinetic analysis of WPCBs were carried out in this study. It showed that the co-existing metals (Cu, Fe, Ni) in WPCBs have positive self-catalytic influence during the pyrolysis process. To illustrate their catalytic effects, the apparent activation energy was calculated by differential model. Contributions of different reactions during catalytic pyrolysis process was studied and the mechanism function was obtained by Šesták-Berggren model. The results showed that Cu, Fe, Ni can promote the reaction progress and reduce the apparent activation energy. Among the three metals, Ni plays better catalytic role than Cu, then Fe. This work provides theoretical base for understanding the three metals’ catalytic influence during the pyrolysis of non-metal powders in WPCBs.

Graphical abstract

Keywords

Waste printed circuit board / Catalyst / Pyrolysis / Kinetics

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Acknowledgements

This work is partly supported by the National Natural Science Foundation of China (Nos. U20A20273 and 21677050). The authors are grateful to the reviewers who help us improve the paper by many pertinent comments and suggestions.

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