Novel Approach for Processing Hazardous Electronic Waste

Rapid urbanization, a general improvement in living standards and increased consumption has resulted in the generation of unprecedented amounts of waste in recent years. Among different wastes, electronic wastes (e-waste) volumes are growing three times faster than any other forms of urban waste. It is estimated that 20 to 50 million tonnes of e-waste are generated worldwide every year. E-waste contains over 1000 different substances; some are toxic and hazardous, which cause serious problems to environment and on human health. Generation of waste residues during recovery of precious metals from e-waste, the presence of hazardous lead, waste plastics, secondary pollution caused by landfilling non-metallic residues are some of the problems associated with recycling e-waste.We report a novel approach to recover valuable materials from waste printed circuit boards; controlled pyrolysis of e-waste was carried out at high temperatures (750-1550 °C) in an argon atmosphere. Segregation of lead and other metals was investigated as a function of temperature and reaction products were analyzed using Inductively Coupled Plasma spectroscopy and Scanning Electron Microscopy. Temperatures above 1350 °C were required to completely remove lead and other metals from e-waste; waste residue that was left behind was predominantly composed of carbon. Further research was carried out on the utilization of lead free non-metallic residue as a carbon source in ironmaking application. Non-metallic residual waste from recycling PCB was found to be a promising reductant in ironmaking applications. This research has laid the foundations of a ‘Zero Waste’ approach for managing and recycling electronic waste.