Raw material criticality studies are receiving increasing attention because an increasing number of metals, performing essential functions in electronics, low-carbon energy and transport technologies face high supply risks. Scarcity of key materials may be a potential barrier to the realization of sustainable energy strategies.
Take the case of indium: Up to 75% of globally refined indium are used to produce indium tin oxide (ITO), used as a transparent conductive layer mainly in LCD and other flat panels, touch panels and electroluminescent lamps. Growing demand is expected especially for small- and medium-sized LCD panels due to growing popularity of smartphones and tablets. Indium has an important role also in manufacturing thin film photovoltaic systems. In addition, light emitting diodes (LEDs) rely on indium as well. There is a concern that these competing uses may result in shortages of high-purity indium. The recent EU study on the resilience to material supply bottlenecks in low-carbon energy and transport concluded that, without mitiagating measures, there could be major supply risks of indium by 2030.
Waste electrical and electronic equipment (WEEE) could be a future source of critical metals. Because there are no good substitutes for indium to be used in ITO thin-film coatings, research has focused on indium recycling from LCD screens. However, current recycling technologies are not efficient in the recovery of indium, and recycling often results in the dissipation of indium and other critical metals in primary metal streams. Research done at the Energy and Environmental Engineering research unit points out that, the view that critical materials in stock are intrinsically recoverable, needs to be revised. As the research of Dr. Jenni Ylä-Mella points out, critical material recovery from stock cannot be approached from the end of life. Firstly, in order to ensure that WEEE could be a future source of critical metals, the reduction of dissipation of critical materials should have much higher priority. Second, more attention should be given to sustainable management of critical materials, especially improved practices at the production and waste management stages. Finally, the need to recover critical materials from WEEE calls for design for recycling: If we want to recover critical materials such as indium from WEEE, electronics will have to be designed such that allows their recovery.
The paper Drivers and constraints of critical materials recycling: The case of indium by Jenni Ylä-Mella and Eva Pongrácz has been published in Resources.
Last updated: 3.5.2017