Depending on the vehicle class, up to 180 kilograms of aluminum can be found in a car. As one of the most important lightweight materials in automotive engineering, the material has a major influence on the reduction of CO₂ in the usage phase of our vehicles. Unfortunately, however, the production of the light metal is very energy-intensive. Alexander Knittel and his team at Mercedes-Benz BodyTEC are working on solutions to close material cycles and conserve resources.
Mr. Knittel, for over half a year now you may officially call yourself an "award winner". What were you and your team honored for?
Yes, we received the Daimler Environmental Leadership Award in the category "Production and process-related environmental protection" for our project "Closed-loop recycling of aluminum”. That made us as a team incredibly proud. It was the recognition for a huge amount of hard work.
What exactly is the project about?
I am responsible for planning and strategy at BodyTEC. BodyTEC is the merger of the two centers for press shop and equipment construction at Mercedes-Benz Cars. In January last year, we sat down with an aluminum manufacturer which also supplies us with aluminum and thought about how a more resource-efficient use of aluminum could look like. The production of automotive aluminum consumes a lot of energy and is extremely CO₂ intensive. On the other hand, it can be recycled almost infinitely and without loss of quality. We wanted to use this property. In addition, the recycling of aluminum produces only five percent CO₂ compared to newly produced aluminum.
So why haven't we been working with recycled aluminum long ago - or even in an aluminum closed loop?
It is not quite that simple. We have always separated aluminum and steel from each other. But in the case of aluminum, we work with two different types of alloys in lightweight body construction: 6000 alloys for outer skin parts such as the hood, fenders or roof and 5000 alloys for reinforcing parts such as the inner part of the doors. In order to close the material cycle and to be able to reuse the aluminum for our purposes, it would have to be recycled according to type. However, since we work with different alloys, we have always returned mixed aluminum residues to the aluminum plants. In addition, sorted aluminum scrap brings in higher profits than mixed aluminum scrap and thus, in addition to the CO₂ savings, also an economic advantage.
That means you were looking for a way to separate the aluminum scrap by type?
Exactly. We tested sorted recycling at our plants in Sindelfingen and Kuppenheim. Those were exciting weeks for our cross-location team because we had to carry out the test during ongoing production operations - without disrupting them.
And - did it work?
Absolutely. We used the different alloys separately for each day. The result speaks for itself. In the four weeks of the test phase, we were able to save almost 2,000 tons CO₂ at the two plants. If you calculate this based on the data for 2021 for the German press plants of Mercedes-Benz Cars, there is an enormous overall potential for CO₂ savings.
That is an impressive number. Does this mean we are now converting our production processes to this?
Of course we are working on the "big" solution. One goal would be to upgrade the technical equipment at our plants so that we can bring as much of our series production process as possible into this recycling closed loop. That is the technical variant. The other variant would be to develop a Uni-Alloy, i.e. a universally applicable aluminum alloy that combines the advantages of both types. This would significantly simplify the following recycling process and would be the much more efficient and long-term method. We are in close contact with the developers for this purpose.
Initiatives like yours show that work is being done at all corners of the company to reduce the CO₂ footprint. How do you perceive these changes?
Change begins on a small scale. I think it is elementary and important, whether privately or professionally, to change for the better what can actually be influenced. And the project has shown: Growth and resource consumption can be decoupled. We have to get to the resources. That will be the future. And only those automotive manufacturers who take this to heart will participate in this future.
What motivates me about my job...
"…to be able to contribute every day to moving a wheel in the big Daimler, which in total makes us more successful every day."
For me, saving resources personally means...
"...to buy much more locally and not always have everything available."
"Thinking outside the box" is important because…
"…otherwise - especially with regard to the transformation – things will not continue."