Copper dissolution into the aqueous sulfuric acid solutions from printed circuit board waste sludge

Abstract

In the present study, the experiment to dissolve copper and iron from the Printed Circuit Board (PCB) sludge waste materials into the aqueous sulfuric acid solution has been done using 1 L glass reactor. Some variables that affected the copper and iron dissolution process such as sulfuric acid concentration, solid sludge percent in the solutions, agitation speed, temperature and dissolution time were investigated in this experiment. Those variable for experiment were covering the sulfuric acid concentration from 5% to 15%, solid sludge percent in the solution from 5 to 20 %, agitation speed from 50 revolutions per minute (RPM) up to 300 RPM, dissolution temperature from 45 to 70 °C and dissolution time up to 120 minutes. The dissolved copper and iron in the aqueous sulfuric acid solutions were analyzed by Inductively Couple Plasma, their residues after dissolution process were analyzed by a Scanning Electron Microscope and X Ray diffraction. The results of experiment show that almost 98% of copper and 89% of iron were dissolved into 15% sulfuric acid solution at temperature 70 °C, and the remaining phase formed in the PCB sludge waste material after dissolution process were BaSO4, SiO2, MgSO4, CaSO4 and Fe2O3.