Recovery of Ag Au and Pt from Printed Ci

Reclamation of printed circuit boards (PCBs) to recover metals is gaining growing attention due to minerals being non-renewable resources. Currently, metals extraction from PCBs through an efficient and green method is still under investigation. The present investigation concerns the recycling of printed circuit boards using hydrometallurgical processes. First, the basic metals (Cu, Ni, Zn and Fe) were separated using a sulfuric acid solution at moderate temperatures. The remaining solids were characterized by SEM-EDS, whereby a high content of precious metals (Au and Pt) was observed. In the second stage, solids were leached with a solution of HCl and NaClO in a L-titanium reactor with varied oxygen pressure (0.2, 0.34 and 0.55 MPa). Results show an Au extraction leaching efficiency of greater than 70% when a temperature of 40 °C and 0.34 MPa of pressure were used. Temperature affects the leaching of metals because HCl begins to decompose at temperatures higher than 53 °C, while Au extraction was greater than 95% when a temperature of 40 °C and a pressure of 0.34 MPa were used with 4 M HCl.