Chapter 5
Recovery of Metals from Electronic
Waste
Abstract The e-waste metal recycling technologies have been advanced to enhance
the recovery efficiency of the metals while reducing the associated environmental
impacts. The pyrometallurgical methods are able to recover precious metals as well as
base metals (Cu, Pb, Sn, etc.) with high purity. The smelting technologies are already
operating in some developed countries. However, the pyrometallurgical plants have
pollution problems due to the disposal of waste gas and slags, emission of dioxin,
particulate matters and toxic gases. The generation of toxic gases is higher in alkali
smelting process along with the production of wastewater with heavy metal ions
content during the leaching process [13]. Hydrometallurgical methods have been
widely used in developing countries. The most reliable options include cyanide
and aqua regia leaching, however, they are associated with environmental concerns
such as toxicity and corrosiveness. The thiourea and thiosulfate leaching methods
have less environmental impacts but they are less economically effective. The halide
leaching method has the advantages of a high recovery rate and less toxicity, but it
has corrosion and technological reliability issues [13]. The biometallurgical methods
are environmentally friendly technologies for metals recovery, as they do not release
toxic gases such as dioxins and furans and do not use large amounts of inorganic
acids, which lowers the health risks to the operators. In addition, they are capable
of extracting all metals from e-waste, while with the pyrometallurgical methods it is
almost impossible to recover lithium and aluminum. The biometallurgical methods
have been under investigation for the past 20 years [21, 34]. An ideal recovery
method is expected to be cost-effective, of a high recovery rate and less environmentally polluting. No individual method is ideal at present, so a combination of the
above methods should be considered.
Keywords Electronic waste · Metal recycling technologies · Physical methods ·
Thermochemical methods · Metallurgical methods · Pyrometallurgical methods ·
Hydrometallurgical methods · Biometallurgical methods
Electronic waste or e-waste is the electric and electronic devices that are near or
at the end of their useful life and no longer satisfy their original purpose. The
© Springer Nature Singapore Pte Ltd. 2021
L. Nazari et al., Advanced and Emerging Technologies for Resource Recovery
from Wastes, Green Chemistry and Sustainable Technology,
https://doi.org/10.1007/978-981-15-9267-6_5
127
Recovery of Metals from Electronic
Waste
Abstract The e-waste metal recycling technologies have been advanced to enhance
the recovery efficiency of the metals while reducing the associated environmental
impacts. The pyrometallurgical methods are able to recover precious metals as well as
base metals (Cu, Pb, Sn, etc.) with high purity. The smelting technologies are already
operating in some developed countries. However, the pyrometallurgical plants have
pollution problems due to the disposal of waste gas and slags, emission of dioxin,
particulate matters and toxic gases. The generation of toxic gases is higher in alkali
smelting process along with the production of wastewater with heavy metal ions
content during the leaching process [13]. Hydrometallurgical methods have been
widely used in developing countries. The most reliable options include cyanide
and aqua regia leaching, however, they are associated with environmental concerns
such as toxicity and corrosiveness. The thiourea and thiosulfate leaching methods
have less environmental impacts but they are less economically effective. The halide
leaching method has the advantages of a high recovery rate and less toxicity, but it
has corrosion and technological reliability issues [13]. The biometallurgical methods
are environmentally friendly technologies for metals recovery, as they do not release
toxic gases such as dioxins and furans and do not use large amounts of inorganic
acids, which lowers the health risks to the operators. In addition, they are capable
of extracting all metals from e-waste, while with the pyrometallurgical methods it is
almost impossible to recover lithium and aluminum. The biometallurgical methods
have been under investigation for the past 20 years [21, 34]. An ideal recovery
method is expected to be cost-effective, of a high recovery rate and less environmentally polluting. No individual method is ideal at present, so a combination of the
above methods should be considered.
Keywords Electronic waste · Metal recycling technologies · Physical methods ·
Thermochemical methods · Metallurgical methods · Pyrometallurgical methods ·
Hydrometallurgical methods · Biometallurgical methods
Electronic waste or e-waste is the electric and electronic devices that are near or
at the end of their useful life and no longer satisfy their original purpose. The
© Springer Nature Singapore Pte Ltd. 2021
L. Nazari et al., Advanced and Emerging Technologies for Resource Recovery
from Wastes, Green Chemistry and Sustainable Technology,
https://doi.org/10.1007/978-981-15-9267-6_5
127