Aluminum is a key raw material for many industrial products. The production of primary aluminum with no recyclate fraction is, however, very energy-intensive. In contrast, the production of secondary aluminum requires about 95% less energy usage. It thus makes sense to collect and recycle as much aluminum-containing waste as possible. Across Europe, only about 50 percent of waste aluminum-containing packaging is currently recycled. The reason for this is the use of aluminum laminates by the packaging industry. Blister packaging, a laminate of PVC and aluminum, is the most widely used packaging in the pharmaceutical industry.
Currently, these materials are recycled via fine grinding to mechanically separate the laminated materials. The resulting aluminum can contain up to 10 percent residual PVC and can hence not be used directly as a recyclate. Thermal post-treatment of such recycled aluminum requires expensive waste gas scrubbing to remove HCl that arises from the PVC fraction. The result is that commercial aluminum recyclates have much poorer quality than primary aluminum.
The objective of the ‘Refined aluminum’ project is to develop an innovative process for recovering high-quality secondary aluminum. The project work is being carried out by the Fraunhofer IVV in collaboration with Neidhardt GmbH. The secondary aluminum will be produced from waste aluminum laminates, such as those used for blister packaging. The process must be commercially viable. The German market for PVC-aluminum laminates alone is currently several thousand metric tons annually. This highlights the enormous potential of the new technology.
The technological approach being used for the innovative separation of the components involves extractive recycling with a modified CreaSolv® Process*. The latter was developed at the Fraunhofer IVV to recycle polystyrene. The aim is total removal of the PVC using selective Green Solvents (non-hazardous, non-VOC). These are biodegradable solvents that are totally recovered after use and returned to the process cycle. The objective is to produce high-purity secondary aluminum and a hard PVC that can be used by the plastics industry. The separated fractions will be characterized in detail in order to determine the commercial viability of the process. Prospective applications and markets are being identified for the products.
The high-quality PVC recyclates have a range of potential uses including for window frames, bank cards, and plastic films.
*CreaSolv® is a registered trade name of CreaCycle GmbH, Grevenbroich