Recycling and circular economy—towards a closed loop for metals in emerging clean technologies

Resource efficiency, energy, and mobility transition are crucial strategies to mitigate climate change. The focus is on reducing the consumption of resources, especially energy and raw materials. While raw materials are the basis of our material world, their excessive consumption over the last decades has also contributed significantly to climate change. However, raw materials, and here especially metals, play a key enabling role as well for climate protection technologies, such as electro mobility, the hydrogen economy, and solar and wind power plants, and also for digitalization. Accordingly, it is necessary to make the use of raw materials much more resource-efficient than before and to use them as purposefully as possible instead of consuming them. Advanced circular economy systems and sophisticated recycling technologies build the backbone for the development of a resource efficient and sustainable society. Closed metal cycles contribute for a paramount share to this by securing relevant parts of the raw material supply for high-tech products and by reducing CO2 emissions in their production at the same time. Interacting steps in multistage treatment processes by mechanical, chemical, and thermal unit operations are challenging but will give a competitive advantage for networks of industry and science that are able to handle that.