With this pilot project, Audi, together with its partners, are taking on the challenge of building a closed material cycle for automotive glass. The plan is part of Audi’s circular economy strategy, with the brand paying attention to all areas of the production chain. Raw materials that play a role in this as far as possible are put back into the production process as soon as they are no longer used. In this way, resources can be saved in development and production and environmental impacts can be reduced throughout the value chain.
For example, aluminum scrap from pressing factory Audi has been used in a similar closed circuit since 2017 and the brand will now also try it with glass. Audi’s goal is to use secondary materials where technically and economically possible. Until recently, the old windshield had not been used for the production of the new one, and Audi wanted to change that.
By recycling broken car windows, less energy and raw materials need to be used in total to produce new car windows. Working in this way can ultimately significantly reduce the demand for key materials, such as quartz sand. Audi plans to use this more sustainable car window in production of the e-tron Q4 series. Audi relies on collaboration with suppliers to develop new material cycles and make the value chain more sustainable.
According to an intensive study, there is more than enough potential: most of the discarded car windows or panoramic roofs are currently being converted into, for example, drink bottles or insulating materials. If this project succeeds in making a new window out of a broken car window, this will have several advantages. In the first example, high quality automotive glass is used for new high quality glass. There is also a positive effect on CO2 emissions, as up to 30 percent less carbon dioxide is emitted than when producing completely new glass.
Step 1: Processing the raw components of broken glass with Reiling
The first step in the trial began with a select number of dealers from the Volkswagen Group, who sent the damaged windows to Volkswagen Original Teile Logistik GmbH. In the next step, the broken window is sent to Reiling Glass Recycling. There they are broken into small pieces and processed. Until recently, recycled automotive glass was mainly used to make glass for beverage bottles. Automotive glass must meet the most stringent requirements, for example in the area of accident safety. Therefore, partner companies want to recycle the broken glass to its original high quality.
To be able to make high quality recycled materials from this used laminated glass, Reiling Glass Recycling uses state-of-the-art equipment. The company first removed materials such as plastic coatings on glass, metal, heating cables, and antenna cables. The removal process is carried out with a magnet, a separator for non-ferrous metals and an extractor.
Step 2: Saint-Gobain Glass and Sekurit make new car glass from shards
In the next recycling step, after the recycled glass has been processed and all possible waste has been removed, Saint-Gobain Glass makes flat glass from its shards. For this purpose, glass grains are first separated by type for clear origin and color inspection, and then stored. The purest and most homogeneous glass recycling is required for the production of new base glass. Saint-Gobain Glass then mixes the recyclate with, among other things, quartz sand, sodium carbonate and lime – the basic components of high quality glass.
The aim of the trial is to convert approximately 40 tonnes of recycled automotive glass into flat glass. The sheet glass is then processed into rectangles with a size of approximately 3 x 6 meters each. After that, the affiliate company Saint-Gobain Sekurit turned flat glass into automotive glass.
Step 3: Application of recycled automotive glass in the Audi Q4 e-tron
The pilot partner has agreed to test the process for one year. If it turns out that the glass can be recycled in an economical and environmentally friendly way, Audi will use the material in the Audi Q4 e-tron.