175
the inappropriate disposal of products; however, today recycling plays a relevant
role in the supply of scarce materials. It is a new method to procure raw materials,
which is called urban mining. Currently, 49 million tons of Electronic-waste is generated every year, and only 10% of that is recycled. In turn, the amount of rare earth
elements recycled is only 1% (Jones 2013).
The critical elements used in the LED industry are the metals indium and gallium
and the rare earth elements europium and terbium. Serra et al. (2015) claim that the
development of lighting technologies is closely linked with the availability of rare
earth elements since these play an essential role in semiconductors.
However, the recycling of LEDs faces hurdles that have to be overcome. Valuable
metals like indium and gallium and rare earth elements like europium and terbium
are found in the inner components of LEDs. Therefore, to recycle them, it is first
necessary to remove the materials used for encapsulation like glass, plastic, ceramics, aluminium, and copper resistors. Gallium and indium are the main critical elements recovered from LEDs, while rare earth elements are not extensively recycled
due to the lack of proper techniques for the purpose. As shown above, techniques
like acid leaching, bacterial leaching, and pyrometallurgical methods may be used
to recover these elements, but the concentration of these elements remains the main
challenge faced by the industry today (Swain et al. 2015a, b, c; Zhan et al. 2015;
Maneesuwannarat et al. 2016a, b). Another difficulty lies in increasing the amount
of recycled material to boost production scale, which is problematic in view of the
incipient character of waste management in many countries.
Concerning production and price of materials, gallium and indium production
values are 216 t/year and 640 t/year, respectively, with prices at US$517/kg and
US$561/kg, in that order. The main rare earth elements used in the production of
LEDs are europium, lutetium, yttrium, and cerium, all of which are used in light
conversion. Annual production values of cerium, europium, lutetium, and yttrium
are 24,000 t, 10 t, 10 t, and 8900 t, respectively, while prices are US$36/kg, US$418/
kg, US$800/kg, and US$7/kg, in that order. In addition, gold, silver, and tin are also
considered critical elements and are widely used in electrical, thermal, and mechanical connections (Fraunhofer Institute 2018).
9.8 Conclusion
The growth of the LED industry shows promise. From the technological standpoint,
it is associated with the search for alternatives for the procurement of critical elements like gallium, indium, and rare earth elements. One of these alternatives is
recycling, which is an important technique when it comes to protecting the environment and recovering critical elements for the production of new LEDs. Several techniques are being investigated, like pyrometallurgy and hydrometallurgy, but the
main challenge is to obtain larger amounts of these elements and to increase scale
in a recycling production chain of critical elements that may be returned to the production line of new LEDs.
9 Recycling Processes for the Recovery of Metal from E-waste of the LED Industry
the inappropriate disposal of products; however, today recycling plays a relevant
role in the supply of scarce materials. It is a new method to procure raw materials,
which is called urban mining. Currently, 49 million tons of Electronic-waste is generated every year, and only 10% of that is recycled. In turn, the amount of rare earth
elements recycled is only 1% (Jones 2013).
The critical elements used in the LED industry are the metals indium and gallium
and the rare earth elements europium and terbium. Serra et al. (2015) claim that the
development of lighting technologies is closely linked with the availability of rare
earth elements since these play an essential role in semiconductors.
However, the recycling of LEDs faces hurdles that have to be overcome. Valuable
metals like indium and gallium and rare earth elements like europium and terbium
are found in the inner components of LEDs. Therefore, to recycle them, it is first
necessary to remove the materials used for encapsulation like glass, plastic, ceramics, aluminium, and copper resistors. Gallium and indium are the main critical elements recovered from LEDs, while rare earth elements are not extensively recycled
due to the lack of proper techniques for the purpose. As shown above, techniques
like acid leaching, bacterial leaching, and pyrometallurgical methods may be used
to recover these elements, but the concentration of these elements remains the main
challenge faced by the industry today (Swain et al. 2015a, b, c; Zhan et al. 2015;
Maneesuwannarat et al. 2016a, b). Another difficulty lies in increasing the amount
of recycled material to boost production scale, which is problematic in view of the
incipient character of waste management in many countries.
Concerning production and price of materials, gallium and indium production
values are 216 t/year and 640 t/year, respectively, with prices at US$517/kg and
US$561/kg, in that order. The main rare earth elements used in the production of
LEDs are europium, lutetium, yttrium, and cerium, all of which are used in light
conversion. Annual production values of cerium, europium, lutetium, and yttrium
are 24,000 t, 10 t, 10 t, and 8900 t, respectively, while prices are US$36/kg, US$418/
kg, US$800/kg, and US$7/kg, in that order. In addition, gold, silver, and tin are also
considered critical elements and are widely used in electrical, thermal, and mechanical connections (Fraunhofer Institute 2018).
9.8 Conclusion
The growth of the LED industry shows promise. From the technological standpoint,
it is associated with the search for alternatives for the procurement of critical elements like gallium, indium, and rare earth elements. One of these alternatives is
recycling, which is an important technique when it comes to protecting the environment and recovering critical elements for the production of new LEDs. Several techniques are being investigated, like pyrometallurgy and hydrometallurgy, but the
main challenge is to obtain larger amounts of these elements and to increase scale
in a recycling production chain of critical elements that may be returned to the production line of new LEDs.
9 Recycling Processes for the Recovery of Metal from E-waste of the LED Industry