Two phase leaching for metal recovery from waste printed circuit boards: Statistical optimization

Abstract

The rapid growth of technology plays an inevitable role in humankind?s life and has a significant stint in the generation of e-waste. The electronic waste possess tremendous environmental and health effects and one such major contributor to it is printed circuit boards (PCBs). The present work deals with the recovery of heavy metals from PCBs by using aqua regia as leaching reagent by two stages (first stage HCl and HNO3 and second stage HCl and H2SO4). The studies carried by Response surface methodology (RSM) to determine the optimal conditions of recovery for the heavy metal ions showed that time 5 hrs, pulp density 25 gm L-1, and temperature 90.10C with desirability 0.761. These optimized values provide maximum recovery rate of Cu (97.06%), Sn (94.66%), Zn (96.64%) and Pb (96.89%) respectively. EDXs is used to analyze the metal concentrations of the sample before and after treatment.