Effect of steam-iron reaction on product characteristics and debromination during pyrolysis of epoxy-printed circuit boards.

Abstract

In this work, the effect of steam and Fe powders on the pyrolysis of epoxy-printed circuit boards (e-PCBs) is in the focus of interest. It was found that higher yields of oil and gas were obtained at 600 °C in steam atmosphere than these obtained in N2 atmosphere. Due to the interactions of Fe powders and steam, the highest yield of H2 was obtained at 600 °C, accounting for 12.2 mmol g-1. In terms of the oil products, a high amount of phenol was produced in steam atmosphere, whereas an increased yield of single ring aromatic compounds was obtained, due to the dehydroxylation reactions promoted by steam-iron reaction. In steam atmosphere, the amount of organobromine compounds was greatly reduced. Fe powders removed most of organobromine compounds and HBr from oils. However, the bromine fixing ability of Fe powders was declined at 700 °C, leading to an increase in the content of inorganic bromine in liquid products. The characterization of spent Fe powders showed that the oxidation reactions of Fe powders with steam proceeded during the experiment, whereas the reduction reactions could be promoted at higher temperatures.