Almost two million tons of scrap metal are generated in Switzerland every year. However, much of it is inadequately sorted and therefore recycled to a lower quality: instead of being used in vehicle construction or the machine industry, it often ends up as building material. Two studies by Lucerne University of Applied Sciences and Arts now show how this "downcycling" can be avoided using intelligent technologies and new approaches and how scrap can be turned back into high-quality metal.
Up to 95 percent of scrap metal in Switzerland ends up in recycling plants. Sounds good, but it’s not necessarily. "The return rate alone says nothing about the quality of recycling," says Simon Züst, research group leader of two studies on the subject at Lucerne University of Applied Sciences and Arts (HSLU). Although the scrap is processed further, it can no longer be used for high-quality applications due to impurities such as copper from cables or tin from can coatings.
One example: copper in steel scrap can no longer be removed during melting. Even the smallest quantities impair material properties such as formability and weldability. The resulting recycled steel is then no longer suitable for safety-relevant parts in vehicle construction or for precise machine components. Instead, it ends up in civil engineering, for example as steel reinforcement (reinforcement) in concrete, where lower demands are placed on quality and purity.
This so-called downcycling is not only economically unattractive, but also strategically problematic: Switzerland has no economically viable ore deposits. "Every tonne that is recycled to a high quality strengthens our independence from imports," emphasizes Züst. A particularly relevant factor in times of trade and economic instability.
Sensors detect scrap metal even before it is processed
In the ReRe Circular Economy for Metals project, the research group investigated, among other things, the role that intelligent sensors in combination with self-learning AI can play when it comes to identifying the material composition of scrap metal when it is delivered to collection points. They can identify critical components such as batteries or pressurized containers, enabling precise and safe sorting.
This not only increases the efficiency of recycling, but also the ecological and economic benefits: According to Züst, if only 15% of returned scrap metal were recycled to a higher quality in future, up to 36,000 tons of CO2 could be saved each year and added value of around CHF 30 million generated annually. According to the International Copper Association (2022), the effect is also significant for other metals such as aluminum, zinc and copper: cleanly recycled copper, for example, retains around 95% of its material value as it can be reused with almost no loss. Currently, only around half of Europe’s copper demand is obtained from recycling. So there is still room for improvement.
Systemic approaches: Thinking better about cycles
The second project funded by Innosuisse, REINVENT, took a close look at the entire metal recycling system: From the material flows to the players to the business models. The aim of the study was to create a basis for a networked, sustainable circular economy for metals in Switzerland.
In addition to technological innovations, binding quality standards, reliable traceability data and economic incentives are required for companies that process metals, generate scrap or are involved in collection logistics and processing. For example, it is crucial that recyclers understand the added value of clean recycling. Only when this is recognized will the willingness and motivation to invest in appropriate measures such as optimized sorting processes increase. Bonus models for particularly sustainable practices are also conceivable. Züst is confident: "The industry is open and willing to innovate."
Key fields of action defined
The two studies by Lucerne University of Applied Sciences and Arts provide a concrete basis for making the metal cycle in Switzerland sustainable, resilient and less dependent on imports. To ensure that high-quality recycling becomes the norm, the researchers recommend, among other things, integrating sensor technologies across the board, establishing standardized data systems for traceability and strengthening cooperation along the value chain. Reuse strategies should also be considered and specifically promoted across the entire system in technological, economic and regulatory terms. For Züst, one thing is clear: "High-quality recycling is not a compromise, but a key to the sustainable supply of raw materials of tomorrow".
