The drawer phones belong to the so-called urban mine. In contrast to the classic raw material mine, this describes the man-made raw material deposits: "All the goods that we humans have ever created," explains Britta Bookhagen from the Federal Institute for Geosciences and Natural Resources (BGR). These so-called anthropogenic deposits include bridges, cars, houses, washing machines - and smartphones. Gold, copper and nickel, for example, can be extracted from cell phones, while steel in particular can be extracted from cars and bridges.

In the strategic consideration of the urban mine, it is initially irrelevant "whether the goods are still being actively used and will only be released in the foreseeable future or whether they have already reached the end of their useful life", writes the Federal Environment Agency (UBA) on its website. Metals and construction minerals in particular often remain in infrastructures, buildings and everyday goods for a long time. "Over decades, enormous stocks of materials have accumulated in this way, which hold great potential as a future source of secondary raw materials."

The vision: becoming less dependent on raw material imports

Felix Müller, responsible for the topic of urban mining at the Federal Environment Agency (UBA): "The vision is to become less dependent on raw material imports; rather, we should become veritable raw material producers with secondary extraction. In this way, we can also open up a new economic field."

© Felix Müller private

According to UBA figures, the German economy uses around 1.3 billion tons of materials domestically every year - this includes products such as cars as well as pure raw materials. Germany is heavily dependent on imports, especially for metal and energy raw materials, according to the BGR's latest raw materials situation report from December. Germany is almost completely dependent on imports, especially for newly extracted metals.

However, the world's raw materials are finite, international competition is growing and costs are rising - as is the pressure on natural areas and their ecosystems. Recycling metals or building materials, for example, can therefore help to conserve the earth's natural resources - and also reduce greenhouse gas emissions, groundwater pollution and biodiversity loss, says Felix Müller, who is responsible for urban mining at the Federal Environment Agency.

And expansion will not only help the environment: "The vision is to become less dependent on raw material imports, but rather to become veritable raw material producers through secondary extraction. That way, we can also open up a new economic field," says Müller. According to him, Germany's anthropogenic deposits are enriched with around 550 million tons of material per year. The expert says: "As long as material stocks continue to grow at this rate, we are still a long way from a sustainable circular economy. But the growing stockpile holds the immense potential to close material cycles far better in the future than we have been able to do so far. We need to set the course for this now and adapt the framework conditions." The German government is therefore also currently working on a national urban mining strategy.

Recycling instead of hoarding

Britta Bookhagen, Head of the Recycling Raw Materials Department at the Federal Institute for Geosciences and Natural Resources (BGR). She clarifies: "Urban mining refers to products at the end of their life." Only when all other avenues, such as repairing or reselling, have been exhausted is it a matter of recycling - "not into the drawer, please", says Bookhagen.

© BGR/M.Sack

"Mining" in the urban mine is not done with a bucket wheel excavator and pickaxe, but by recycling - and so to a certain extent it is also a task for society as a whole, says geologist Bookhagen. However, she clarifies: "Urban mining refers to products at the end of their life." Only when all other options, such as repairing or reselling, have been exhausted is it a matter of recycling - "not into the drawer, please", says Bookhagen.

There is currently a veritable treasure trove of gold in German drawers. In a 2020 study, Bookhagen and her colleagues came to the conclusion that the approximately 200 million smartphones in German drawers contain around 3.4 tons of gold, 1,300 tons of copper and 520 tons of nickel, among other things. In a report published on Monday, researchers from the Cologne Institute for Economic Research calculated that the value of the metal in unused cell phones is around 240 million euros. In view of the material value of smartphones sold in 2021 of 23.5 million euros, the drawer phones could therefore cover the material requirements for new smartphones for over ten years. However, the authors themselves qualify the calculation: The reality looks different, "as not all drawer phones are sent for recycling and are also completely recyclable".

Better data situation desirable

This is precisely the biggest difficulty with urban mining, says expert Bookhagen: "It is very difficult to estimate which raw materials will come back to us, how and when." On the one hand, it is not at all clear how much steel or aluminum was used in a car or washing machine 50 years ago, nor how it can be most effectively recovered and processed. Better data is needed here. "One thing is certain: The urban warehouse is growing and has a high recyclable material content."

Recovering raw materials from urban mines has great potential to become less dependent on raw material imports and rising costs, says Bookhagen. Germany and Europe are doing well compared to other parts of the world. "But we mustn't forget: even if we could get everything out of the urban mine, it wouldn't cover our demand for raw materials," the expert continues. The hunger for raw materials is too great for that.