Recovery of copper from scrap printed circuit board: modelling and optimization using response surface methodology

The aim of the present investigation is to recover the copper, tin, lead and nickel from scrap printed circuit boards. Leaching and electrowinning have been employed to separate and recover these metals. Two stage leaching was employed wherein the first stage consisted of leaching the scrap board with 0.1 M CuCl2 and 3.0 M HCl resulting in the dissolution of tin only. In the second stage leaching, the residue of the first stage was treated with 0.5 M CuCl2 and 3.0 M HCl resulting in the dissolution of copper, nickel and lead from which lead is precipitated as PbCl2 by cooling. Next the electrowinning was employed to recover copper from a solution containing copper and nickel. Electrolysis was carried out in a two compartment cell divided by a cationic exchange membrane. A Box-Behnken experimental design has been applied to relate the current efficiency with current density, ratio of cuprous to cupric ion concentration, concentration of hydrochloric acid and electrolysis time. The current efficiency was found to increase with current density and concentration of cuprous ion. (C) 2014 Elsevier B.V. All rights reserved.