Characterization of Printed Circuit Boards for Metal and Energy Recovery after Milling and Mechanical Separation

The proper disposal of electrical and electronic waste is currently a concern of researchers and environmental managers not only because of the large volume of such waste generated, but also because of the heavy metals and toxic substances it contains. This study analyzed printed circuit boards (PCB...

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Bibliographic Details
Published in:Materials 2014-06, Vol.7 (6), p.4555-4566
Main Authors: Bizzo, Waldir A, Figueiredo, Renata A, de Andrade, Valdelis F
Format: Article
Language:English
Subjects:
Aluminum
Boards
Cadmium
Contamination
Copper
Density
Hazardous materials
Hazardous wastes
Heavy metals
Personal computers
Precious metals
Printed circuit boards
Printed circuits
Recycling
Separation
Silver
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Summary:The proper disposal of electrical and electronic waste is currently a concern of researchers and environmental managers not only because of the large volume of such waste generated, but also because of the heavy metals and toxic substances it contains. This study analyzed printed circuit boards (PCBs) from discarded computers to determine their metal content and characterized them as solid waste and fuel. The analysis showed that PCBs consist of approximately 26% metal, made up mainly of copper, lead, aluminum, iron and tin, as well as other heavy metals such as cadmium and nickel. Comparison with the results of other studies indicated that the concentration of precious metals (gold and silver) has declined over time. Analysis of the leachate revealed high concentrations of cadmium and lead, giving the residue the characteristics of hazardous waste. After milling the PCBs, we found that larger amounts of metal were concentrated in smaller fractions, while the lightest fraction, obtained by density separation, had a gross calorific value of approximately 11 MJ/kg, although with a high ash content. Milling followed by density separation proved potentially useful for recovery of metals and energy-rich fractions.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma7064555