Recuperation of gold from waste printed circuit boards of small electronic devices

Nowadays, bigger electronic devices are getting replaced by smaller ones due to rapid technological modernization. Printed circuit boards (PCBs) present in these discarded small devices contain valuable metals-like gold, silver, palladium and platinum along with some toxic metals. Recuperation of metals from such small electronic devices will not only conserve natural resources but also protect the environment from pollution. Keeping in view the above, present paper reports feasible processes developed at CSIR-NML for selective recovery of gold from waste PCBs of small electronic devices using hydrometallurgical route. First method involves selective leaching followed by adsorption/cementation to get pure gold metal whereas the second process is related to selective dissolution of non-ferrous metals leaving gold in the residue. In both the processes, gold obtained was highly pure (99.99%). The effluent generated was treated with standard procedure and recycled to the system.