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5 Recovery of Metals from Electronic Waste
rapid growth of technology and consumption-driven societies have resulted in the
production of excessive amounts of e-waste making one of the world’s leading solid
waste. Repairing and upgrading the existing electronic products are difficult for the
consumers due to the design and changing technologies of the devices as well as
discontinuing support from the companies for older models of electronic devices
[1]. This can adversely affect the environment as it increases the need for the mining
and procurement of the materials as well as the production of large quantities of
e-waste. Between 40 and 50 Mt (million metric tonnes) of e-waste, accounting for
about 5% of the total solid wastes worldwide, is being produced globally each year. It
is expected that e-waste production would increase by 500 times in the next decade,
which makes e-waste a fast-growing waste stream [2–4]. Europe and the United
States contribute to half of the e-waste generated annually globally, of which around
22% is from the United States alone [1, 5].
E-waste can be classified based on their composition and components such as
ferrous and non-ferrous metals, glass, plastics, pollutants, etc. One of the most widely
accepted classifications is based on the European Waste Electrical and Electronic
Equipment (WEEE) Directive that divides the e-waste into ten categories [6]:
(1) Large household appliances including cooling and freezing appliances,
washing machines and dryers, electric cooking stoves, microwaves, electric
fans, air conditioners, etc.
(2) Small household appliances including vacuum cleaners, coffee machines, hair
cut machines, toasters, grinders, etc.
(3) Information Technology (IT) equipment including personal computers,
laptops, cell phones, telephones, printers, monitors, etc.
(4) Consumer electronics such as TVs, radios, video recorders, musical instruments, etc.
(5) Lighting equipment such as lamps and luminaires,
(6) Electric and electronic tools (with the exception of large-scale stationary
industrial tools) such as sewing machines, drills, milling equipment, grinding
equipment, soldering irons, etc.
(7) Toys and sporting goods including video games, electric trains, sports
equipment with electric elements, etc.
(8) Medical devices (with the exception of all implanted and infected products)
including analyzers, radiotherapy equipment, cardiology, dialysis, ventilators,
etc.
(9) Monitoring and control instruments such as smoke detectors and thermostats
(10) Automatic dispensers for money, hot or cold drinks, solid products, etc.
Many metals such as gold, silver, copper, nickel, platinum, palladium, lithium,
cobalt and other valuable elements are used in making electronic devices. They
also contain toxic elements including lead, mercury, cadmium, PVC plastics and
hazardous chemicals. E-waste can cause serious environmental and health problems
if not properly disposed of. Dumped electronics in landfills can leach dangerous
chemicals to the groundwater. The large amount of lead in leached water could
5 Recovery of Metals from Electronic Waste
rapid growth of technology and consumption-driven societies have resulted in the
production of excessive amounts of e-waste making one of the world’s leading solid
waste. Repairing and upgrading the existing electronic products are difficult for the
consumers due to the design and changing technologies of the devices as well as
discontinuing support from the companies for older models of electronic devices
[1]. This can adversely affect the environment as it increases the need for the mining
and procurement of the materials as well as the production of large quantities of
e-waste. Between 40 and 50 Mt (million metric tonnes) of e-waste, accounting for
about 5% of the total solid wastes worldwide, is being produced globally each year. It
is expected that e-waste production would increase by 500 times in the next decade,
which makes e-waste a fast-growing waste stream [2–4]. Europe and the United
States contribute to half of the e-waste generated annually globally, of which around
22% is from the United States alone [1, 5].
E-waste can be classified based on their composition and components such as
ferrous and non-ferrous metals, glass, plastics, pollutants, etc. One of the most widely
accepted classifications is based on the European Waste Electrical and Electronic
Equipment (WEEE) Directive that divides the e-waste into ten categories [6]:
(1) Large household appliances including cooling and freezing appliances,
washing machines and dryers, electric cooking stoves, microwaves, electric
fans, air conditioners, etc.
(2) Small household appliances including vacuum cleaners, coffee machines, hair
cut machines, toasters, grinders, etc.
(3) Information Technology (IT) equipment including personal computers,
laptops, cell phones, telephones, printers, monitors, etc.
(4) Consumer electronics such as TVs, radios, video recorders, musical instruments, etc.
(5) Lighting equipment such as lamps and luminaires,
(6) Electric and electronic tools (with the exception of large-scale stationary
industrial tools) such as sewing machines, drills, milling equipment, grinding
equipment, soldering irons, etc.
(7) Toys and sporting goods including video games, electric trains, sports
equipment with electric elements, etc.
(8) Medical devices (with the exception of all implanted and infected products)
including analyzers, radiotherapy equipment, cardiology, dialysis, ventilators,
etc.
(9) Monitoring and control instruments such as smoke detectors and thermostats
(10) Automatic dispensers for money, hot or cold drinks, solid products, etc.
Many metals such as gold, silver, copper, nickel, platinum, palladium, lithium,
cobalt and other valuable elements are used in making electronic devices. They
also contain toxic elements including lead, mercury, cadmium, PVC plastics and
hazardous chemicals. E-waste can cause serious environmental and health problems
if not properly disposed of. Dumped electronics in landfills can leach dangerous
chemicals to the groundwater. The large amount of lead in leached water could