Fast copper extraction from printed circuit boards using supercritical carbon dioxide

•Alternative technology to recycling PCBs.•Supercritical CO2 with H2SO4 and H2O2 was efficient to Cu recovering from PCBs.•Supercritical extraction was 9 times faster than an atmospheric extraction.•Cu supercritical CO2 extraction without H2O2 did not was efficient.•About 90% of Cu was recovered in...

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Bibliographic Details
Published in:Waste management (Elmsford) 2015-11, Vol.45, p.289-297
Main Authors: Calgaro, C.O., Schlemmer, D.F., da Silva, M.D.C.R., Maziero, E.V., Tanabe, E.H., Bertuol, D.A.
Format: Article
Language:English
Subjects:
Atmospheric pressure
Boards
CARBON DIOXIDE
Carbon Dioxide - chemistry
Cell Phone
CIRCUIT BOARDS
Copper
Copper - chemistry
Cu extraction
E-waste
Electronic Waste - analysis
Environment
Extraction
EXTRACTIVE METALLURGY
Hydrogen Peroxide - analysis
Leaching
Mobile phone PCBs
OXIDES
PRESSURE
PRINTED CIRCUITS
Recycling
Recycling - methods
Sulfuric Acids - analysis
Supercritical CO2
Supercritical leaching
Waste Management - methods
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Summary:•Alternative technology to recycling PCBs.•Supercritical CO2 with H2SO4 and H2O2 was efficient to Cu recovering from PCBs.•Supercritical extraction was 9 times faster than an atmospheric extraction.•Cu supercritical CO2 extraction without H2O2 did not was efficient.•About 90% of Cu was recovered in 20min with supercritical CO2 modified. Technological development and intensive marketing support the growth in demand for electrical and electronic equipment (EEE), for which printed circuit boards (PCBs) are vital components. As these devices become obsolete after short periods, waste PCBs present a problem and require recycling. PCBs are composed of ceramics, polymers, and metals, particularly Cu, which is present in highest percentages. The aim of this study was to develop an innovative method to recover Cu from the PCBs of old mobile phones, obtaining faster reaction kinetics by means of leaching with supercritical CO2 and co-solvents. The PCBs from waste mobile phones were characterized, and evaluation was made of the reaction kinetics during leaching at atmospheric pressure and using supercritical CO2 with H2O2 and H2SO4 as co-solvents. The results showed that the PCBs contained 34.83wt% of Cu. It was found that the supercritical extraction was 9 times faster, compared to atmospheric pressure extraction. After 20min of supercritical leaching, approximately 90% of the Cu contained in the PCB was extracted using a 1:20 solid:liquid ratio and 20% of H2O2 and H2SO4 (2.5M). These results demonstrate the efficiency of the process. Therefore the supercritical CO2 employment in the PCBs recycling is a promising alternative and the CO2 is environmentally acceptable and reusable.
ISSN:0956-053X
1879-2456
DOI:10.1016/j.wasman.2015.05.017