Eco-friendly recovery of metals from waste mobile printed circuit boards using low temperature roasting

The substantial growth of electronic waste (e-waste) in recent years has become a serious threat to environment. However, there is an excellent opportunity to recover and reuse metals present in e-waste, which eventually leads to conservation of natural resources for future generation. A greener and sustainable approach for the recovery of metals from electronic waste is the need of the hour. In this study, thermal decomposition of printed circuit boards (PCBs) was carried out in presence of nitrogen for conversion of polymers into oil and combustible gases. The metal rich pyrolysis residue was roasted in presence of ammonia chloride as chlorinating agent to recover metals. The effect of roasting parameters on the metal recovery investigated in temperature range of 200 °C to 325 °C for 1 h to 5 h while the NH₄Cl dosage varied from 1 g/g to 4 g/g. Under the optimized roasting conditions, around 93% Cu, 100% Ni, 100% Zn, and 100% Pb were recovered at temperature of 300 °C, time of 4 h and NH₄Cl dose of 3 g/g. The present process provides an eco-friendly solution for the recovery of metals from e-waste, which are valuable and avoid pollution.