Aluminium is an indispensable cornerstone of European manufacturing with numerous applications in various sectors such as transportation, construction, packaging, and consumer goods. Owing to its inherent lightweighting potential, an increased use of aluminium is a prerequisite to meet the demands of the Green Deal in the transportation and construction industries. Primary production of aluminium has a substantial environmental impact, causing almost 2% of the global human-caused emissions in 2020 (1 billion metric tons of CO2-equivalents ). In addition to long-term environmental issues caused by primary production residues (red mud), the largest impact is generated by the high energy consumption of alumina reduction. Recycling of existing End of Life (EoL) and production aluminium uses only 5% of that energy, making it key to realize the material’s global decarbonisation potential .
The attractive technological features of aluminium alloys are obtained through a large variety of alloying elements, depending on needs of individual applications. However, once aluminium has component metals mixed with it to create an alloy, it is virtually impossible to separate the elements again. Except for single closed-loop industries (beverage cans, some extrusion products), EoL scrap today contains a mixture of different alloys and thereby impurity elements. This mixing of EoL alloy classes leads inevitably to significant downcycling, mostly into robust low- to medium performance cast alloys. They cannot be used in the largest fraction of modern aluminium products which are wrought products, because these have inherent low tolerance for impurity elements.
Downcycling practice has been a successful strategy in the past, due to the high demand for cast aluminium alloys to produce combustion engines, but the shift towards electrified transportation will dry up this universal recycling “sink”. Prognoses estimate an amount of “surplus scrap” (i.e. scrap unsuitable for re-use with current technologies and alloys) of 6 million tons by 2030 and 18.3 million tons by 2050, causing more than 260 million tons of CO2-equivalents by primary substitution. The European aluminium industry is dominated by downstream industries (i.e. manufacturing), with very limited natural resources for primary production. This means that Europe possesses a rich potential of secondary resources with an expected share of 49% of total aluminium production by 2050. To fully exploit this resource, all stages of circular production must achieve substantial progress:
- Alloy designs must increase their impurity tolerance at level or superior performance
- Sorting and dismantling of EoL scraps must exploit the benefits of digitization and robotic assistance to create waste (recyclate) streams with vastly enhanced purities
- Production chains must be adapted to exploit the potential of secondary resources
