Phenol production from pyrolysis of waste printed circuit boards: life cycle and techno-economic assessment

Waste printed circuit boards (PCBs) are a target for urban mining operations due to the abundance of valuable metals in this waste stream and the large quantities generated annually. While metals are conventionally the focus of materials recovery efforts, organic materials can also be recovered, typically by pyrolysis. In this study, we define a hypothetical yet realistic process, derived from existing literature, for the pyrolysis of waste PCBs to produce pyrolysis oil, followed by purification to produce phenol. We use life cycle assessment to evaluate the environmental impact of the secondary phenol production process and compare it to primary phenol production from crude oil, both assuming industrial-scale processes. We also study the potential profitability of secondary phenol production through techno-economic assessment, considering market volatility for phenol. We hope that the clear environmental benefits associated with producing phenol from waste PCB pyrolysis and potential profitability will motivate future experimental studies to refine process details for industrial application.