The Second Life of Metals — Why the Economy needs more than Recycling

We live on a finite planet — but we operate economically as if its resources were unlimited. We extract, process, and use raw materials, and finally we dispose of them. This linear principle has carried our prosperity for decades. But it is not sustainable for the future. We need to rethink, in the words of the American cult television host Fred Rogers: “When you think you’re at the end of something, you’re often at the beginning of something else.”

This is especially true for metals. Aluminum, magnesium, or titanium are found in airplanes and cars, in buildings, medical technology, and many other everyday products. At the same time, their extraction and production are energy-intensive and involve interventions in the environment. In Europe, we are also dependent on international supply chains for numerous metallic raw materials and their processing. The past few years, at the latest, have shown that this dependency is not just an economic issue, but also a strategic risk.

The conclusion: we must make better use of the raw materials we have.

From Consumption to the Loop

The circular economy is often equated with recycling. But recycling is actually only the last step of a much larger idea: a product should be used, repaired, reused, or repurposed for as long as possible. Only when this is no longer possible should its materials be recovered in a way that allows new products to be created from them.

“Reduce, reuse, and recycle” therefore belong together. Already during the development of a product, we need to consider how it can later be broken down into its components and how the materials can find a new use.

This is particularly worthwhile for metals. Aluminum, for example, can be recycled using only a fraction — 5 percent — of the energy needed for its initial production. This means: reused aluminum saves not only primary raw materials but also energy — and therefore CO₂.

That sounds like a simple solution. But it is not.

A Metal Has a History

A component changes throughout its life. It is heated and cooled, mechanically stressed. Exposed to moisture, salt, or other environmental influences. It corrodes and ages. During recycling, different alloys and impurities often come together.

The material that comes back at the end of its life is therefore not the same material it was at the beginning.

This is exactly where a central task of modern materials research begins. We not only need to know which material is in front of us. We need to understand what it has experienced, what properties it has today, and for which new application it is suited.

At the Helmholtz-Zentrum Hereon, we work intensively on these questions. We study, for example, lightweight metals such as magnesium as well as titanium, research corrosion and degradation processes, and develop methods that allow us to understand how materials change during their use. Modern characterization methods increasingly allow us a deep look into their structures.

We are working on the reuse of magnesium for the mobility of the future. Magnesium is the lightest of all structural metals — around three times lighter than steel. The immense advantage therefore lies in weight savings combined with high strength, which saves energy — that is, fuel — especially in vehicle and aircraft construction.

More concrete examples: our hydrogen researchers use metallic waste to efficiently store the energy carrier within it. They require much less pressure and more moderate temperatures compared to conventional tanks. At our site in Teltow, we have developed a recyclable “ink” based on lignin, a wood by-product, for 3D printing. The printed objects can be dissolved through simple contact with water and then recycled.

The goal is not to reuse every material for the same purpose at any cost. What matters, rather, is finding the most sensible next use in each case.

The Digital Life Record of a Material

This is where digitalization opens up new possibilities. Let us imagine that a material had a digital life record, a kind of passport. That is exactly what we are working on at Hereon.

Individual measurement values become a material history. Of course, at this point everyone suspects that computing power comes into play. Data spaces could make information available along value chains. Sensor technology and automated processes could identify and sort materials. Artificial intelligence can bring together large amounts of material, process, and usage data and derive predictions about remaining properties from it.

The question would then no longer simply be: can we recycle this metal? But rather: what is the best next use for this material? That is a major difference: because a functioning circular economy needs not only material flows. It needs knowledge about them.

Dependency Can Become Expertise

This gives the circular economy an additional dimension. Europe may have few mineral resources, but it does have industrial infrastructure, extensive material stocks, and enormous scientific and technological expertise.

Our cities, vehicles, machines, and infrastructures are therefore also raw material stores. The question is whether we are capable of recovering the materials contained within them at high quality and putting them to new use.

More Than Recycling

A circular economy is more demanding than our previous linear model. Products must be designed differently, material flows documented, data made available across company boundaries, and secondary materials reliably characterized. For this, we need new technologies, standards, and business models — we need to rethink value chains and build technological sovereignty.

The effort is worth it! Because on a finite planet, an economic system that permanently depends on ever more primary resources puts itself at a disadvantage. Moreover, it does not reflect the true costs of raw material extraction for the climate, the environment, and people.

Metals have a decisive advantage: we can breathe a second life into them. And a third, and many more. Perhaps, in the future, we should therefore talk less about waste and more about the next use of a material — from the bottle cap to the aircraft fuselage. Materials research, digitalization, and artificial intelligence can make exactly that possible.

The longest possible life, and a new beginning. Who wouldn’t wish for that?