Thermodynamic Study of Leached Metals (Cu, Zn and Ni) from Waste Printed Circuits by Electrochemical Method

A thermodynamic study (Pourbaix type diagrams, using the software Hydra/Medusa) of acid leaching solutions to obtain the electrochemical recovery of Ni, Cu and Zn present in printed circuit boards is reported. Solutions were characterized by atomic absorption spectroscopy at room temperature. The metals were leached in a 0.9237 M H2SO4 solution (pH = 1.56) at temperatures of 313, 323, 333 and 343 K. From this data, the reduction potentials were determined for each metal, finding the values of -0.0024, -1.1274 and-0.5892 V vs calomel for Cu, Ni and Zn, respectively. Displacement in the reduction potential with the increase of the metal concentration in the leaching solution was observed.