Transparent recycling

It forms part of the brand’s commitment to finding new ways of conserving materials and wherever possible, recycling waste or overmaster into new, viable base materials. This ‘closed loop’ system is being used extensively through Audi’s operations, the closed aluminium loop one story of success which has already seen Audi become the first car manufacturer to be awarded the ‘Chain of Custody’ – the certificate of the Aluminium Stewardship Initiative.

Now, Audi is tackling the challenge of establishing a closed material cycle for car glass as part  of a one-year pilot project. Recycling damaged class into new windowpanes which will save not only resources, but also energy and water in window manufacturing. 

In Audi’s pilot project, irreparably damaged car windows first go to a company called Reiling, where the old windows are broken into small pieces and processed. 

“Until now, recycled material has mostly been turned into beverage bottles,” explains Daniel Rottwinkel, Plant Manager at Reiling. And that is precisely where the joint pilot project starts –  recycling damaged glass back to its original quality for car windows. In order to be able to produce recyclable material from old glass, the company meticulously sorts out non-glass materials like the PVB plastic layer (polyvinyl butyral) in the glass, window edgings, metals, and wires. The elimination process is carried out using magnets, non-ferrous metal separators, extraction units and electro-optical sorting units.

Once Reiling has processed the glass recyclate and removed all the waste materials it can, another firm, Saint-Gobain Glass turns it into plate glass rectangles 3 x 6 metres in size at its float line in Herzogenrath, Germany. 

Along with the shards, Saint-Gobain also mixes the recyclate with basic glass components that do not come from automotive sources, like quartz sand, sodium carbonate, and chalk, at a ratio of 30-50 percent. 

“For us, this cycle of making new car windows out of defective ones is an important step toward producing automotive glass in a way that conserves resources and energy,” says Dr. Markus Obdenbusch, production manager in charge of the Saint-Gobain site. 

“We’re just starting to look at glass as a recyclate, so we anticipate that there will be more potential for improvement,” Obdenbusch says. Beyond the pilot project with Audi, Saint Gobain plans to put up to 30,000 tons of shards into production in Herzogenrath within the next three years, which will in turn save energy and reduces carbon emissions. 

The three partner companies will put the process to an initial one-year test so that they can learn about material quality, stability, and costs. If glass can be recycled in an economical and ecologically meaningful way, the resulting car windows will be used in the Audi Q4 e-tron series.

The pilot project is just one more example of how Audi and its partner companies are working to move materials into intelligent cycles. The goal is to use secondary materials wherever that is technically possible and economically sensible to do so in order to shape value chains more sustainably and conserve resources.