Research on high-temperature fast pyrolysis of waste printed circuit boards for gas release and carbon structure evolution.

Abstract

Pyrometallurgy has proven to be a highly effective method for the large-scale recycling of waste printed circuit boards (WPCB) in industrial settings. This study focused on the fast pyrolysis characteristics of WPCB at smelting temperatures and characterized the gas product release behavior and solid product features in detail. The results indicate that the pyrolysis gas was mainly composed of H₂, CH₄ and CO, and the maximum yield of pyrolysis gas was obtained at 1300 °C, which was 233.66 mL/g. The retention of copper and tin decreased from 98.61 % and 92.39 % to 87.98 % and 70.66 %, respectively, when the temperature increased from 800 °C to 1300 °C. The structure of the glass fibers in the WPCB remained invariant, whereas the carbon fraction progressively tended to graphitize. The results of Py-GC/MS analysis indicate that high temperatures and extended residence times were more favorable for the formation of small molecules such as alkenes and aromatics and inhibited the production of brominated contaminants.