Abstract
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, Ag and Pt) was observed. In the second stage, solids were leached with a solution of HCl and NaClO in a 1-L titanium reactor with varied oxygen pressure (0.2, 0.34 and 0.55 MPa), temperature (40, 50 and 80 °C) and concentration of HCl (2 and 4 M), obtaining extractions above 95% at [HCl] = 4 M, P = 0.34 MPa and T = 40 °C. The extraction increased depending on the concentration of HCl. Eh–pH diagrams for Ag–Cl–H2O, Au–Cl–H2O and Pt–Cl–H2O were constructed to know the possible species in the solution.
Highlights
Technology has recently advanced by leaps and bounds, and the production of electronic and electrical equipment (EEE) increases day by day
The 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
Eh–pH diagram for the Au–Cl–H2O system, with [Au] = 0.00036 M, 40 °C and 0 leaching efficiency of platinum in these conditions was greater than 98%
Summary
Technology has recently advanced by leaps and bounds, and the production of electronic and electrical equipment (EEE) increases day by day. The increase in waste originating from electrical and electronic equipment (WEEE) traces back to both private homes and professional users [1,2]. These materials are not properly treated when they reach the end of their useful life because they are sent untreated to landfills. Equipment components (heavy metals, plastics, polymers, ceramics, etc.) represent an important contamination source with severe ecosystem and health ramifications. In recent years, concern has been growing for the environment worldwide [3]
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