Aluminum Alloys in Autobodies: Sources and Sinks

Emissions from the transportation industry combined with increasing consumption of materials have inspired the automotive industry to use lightweight materials in auto-bodies. A wide diversity of materials is being used, for example, aluminum, magnesium, and plastic composites. This light weighting approach is a proven sustainability strategy improving fuel economy and thereby reducing greenhouse gas emissions. However, increasing the number of differing types of materials in cars is actually complicating recycling operations. Critical metals used as alloying additions are dissipatively lost in the recycling process and can also negatively impact recycling rates by accumulating as tramp elements. This work combines compositional characterization of automotive materials, material flow analysis, and techno-economic assessment to better understand this problem and inform solutions. Results show that both technical solutions like sensor-based sorting and operational solutions like compositionally based blending can decrease material losses, thereby reducing the negative impacts and inching closer to a circular economy.