Upcycling scrap metal

Cars, tools, household appliances: many of the most common and useful tools of daily life are made of metal. Currently, recycling them requires their metal parts to be melted down in an energy-intensive process. Researchers in the “2nd Life Metal Components” project at TUD Dresden University of Technology (TUD Dresden) are pursuing a clever solution to replace this high-energy step.

The TUD Dresden researchers led by Professor Alexander Brosius and Professor Andrés Fabián Lasagni are developing novel methods to directly cut apart scrap metal, press the pieces into flat sheets, then weld the sheets together again and mould them into new forms. ThIS approach brings energy savings of ninety percent compared to metal recycling processes that rely on melting.

One of the biggest challenges in the project is finding a way to process the very different sizes and shapes of scrap steel and aluminium parts, which also have varying degrees of thickness, strength and quality. In standard practices, the melting process is what reliably creates a uniform product for the subsequent metalworking processes.

To meet this challenge, the researchers are developing entirely new process chains, including macrostructured deep drawing—a technology developed at TUD Dresden that enables processing sheet metal of uneven thickness. At present, the metal parts created with this method are less uniform than conventionally recycled metal, but the researchers are convinced that their components nonetheless meet the specifications for a wide range of applications.

However, the project encompasses much more than recycling metal: another focus is enhancing the properties of reprocessed metal parts. For this step, the researchers use a laser to etch minuscule structures of just a few micro- or nanometres into a metal’s surface—thereby rendering the surface resistant to water, dirt or bacteria. The advantages are many: boosting corrosion protection in metal components, for instance, or ensuring that surfaces in the food industry remain germ-free.