Multi-recycling – a strong argument for tinplate packaging

Sustainability is the driving factor in the packaging industry, dueto consumers’ increased environmental awareness

In a representative survey commissioned by tinplate manufacturer thyssenkrupp Rasselstein in Germany in 2020, 41% of consumers reported the sustainability of packaging to be a major influence on their purchasing decisions. This is where packaging recyclability comes into play: Material that can be recycled after use and does not have to be newly produced saves both energy and resources. This is especially true for the food can made of packaging steel because CO2 emissions can be significantly reduced by the way tinplate products are recycled into new
high-quality steel products – the keyword is multi-recycling. In practice, this means that even recycled packaging steel can be recycled over and over again. “Tinplate is a permanent material in a closed cycle that is almost 100% recyclable. And it can be recycled almost infinitely and without downcycling, thus without any reduction in quality,” said Andreas Knein, Managing Director of DWR - Deutsche Gesellschaft für Weißblechrecycling mbH, a subsidiary of tinplate manufacturer thyssenkrupp Rasselstein GmbH.

Compared to primary production, resources and CO2 are saved with each cycle of tinplate recycling. After seven recycling processes, 4.6 tons of steel products have been produced from the original one ton of steel. The recycling of one ton of steel and iron scrap saves 1.6 tons of iron ore, 0.65 tons of coal, and 0.3 tons of limestone. “By using scrap in steel production, we are also using 70% less energy compared to primary production. The emissions of a product made from tinplate are therefore falling with each recycling process, as significantly less energy is used than if the steel were produced purely from iron ore. After just the sixth cycle, emissions have more than halved,” Knein explained.

Material cycle closes in the steel mill
During the recycling process, it is continually attempted to make tinplate recycling even more sustainable. The consistent separation of waste and raw materials such as tinplate is an important step in this direction. In Germany, emptied tinplate packaging is collected by way of the dual systems from consumers and is subsequently sorted. Thanks to its inherent properties – in this case magnetism – tinplate is easily separated from waste in the sorting facilities. For further processing, tinplate scrap is then taken to processing centers where the material is shredded by machines and separated from residual contents, labels, or other impurities. To optimally condition the raw material for further use, the material is pressed into scrap bundles. The now very clean tinplate scrap is transported to the steel mill, where it is melted down without loss of quality and processed with pig iron from the blast furnace to produce crude steel. After several product-specific processing steps, it is recycled into a new high-quality steel product, from car sheet to steel beams to new packaging. Every steel mill can therefore also be considered a recycling plant. The material cycle is closed.

The route via processing plant to steel mill ensures that no undesirable materials are burnt along with the steel scrap when it is melted down so that no unnecessary emissions are caused. The separated mostly organic residues are used to generate energy. This upstream treatment step is not only common in Germany. Disruptive materials such as plastics are also removed in other EU member states. “At EU level, we are observing a trend towards higher steel qualities, even if it means accepting another intermediate step on the way to recycling. Be it through further processing plants or through additional manual steps in sorting plants as is often the case in other European countries,” said Andreas Knein.

Tinplate is the recycling leader in Europe
Since tinplate has excellent recyclability, consumers, manufacturers, and retailers in the packaging sector can contribute to protecting the environment and reducing CO2 by choosing packaging steel, a material with a closed material cycle. At a current recycling rate of 84% in Europe, tinplate is the front-runner among all packaging materials. To further increase the overall rate, however, more consumer education is needed. Above all, waste separation is a topic that still needs addressing. “All those involved – from manufacturers to retailers, from the dual systems to the recycling industry – must offer better information to the public on waste separation. This is the only way to guarantee that products such as food cans end up in the right bin and that important resources are available to the recycling loop. In this way, it is possible to further improve both multi-recycling and the ecological performance of tinplate packaging,” said Andreas Knein.

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