Industrial Steinert LIBS-Based Sorting of Post-Consumer Wrought Aluminum Alloys for Automotive Applications

Recycling wrought aluminum alloys are essential for reducing energy use and greenhouse gas emissions in the automotive manufacturing sector. However, post-consumer aluminum material streams are highly heterogeneous and often contaminated, which frequently leads to downcycling and limits their reuse in high-value applications. This study evaluates the industrial-scale implementation of a Steinert LSS laser-induced breakdown spectroscopy (LIBS) sorting system for the automated sorting of 5xxx, 6xxx, and 7xxx series aluminum alloys under industrial conditions. To measure sorting accuracy, process scrap was used and post-consumer scrap was sorted and then melted for chemical verification using optical emission spectrometry (OES). The results demonstrate 92% classification accuracy for clean process scrap and 69% for painted process scrap. Melt composition analysis confirms that 6xxx series alloys consistently met predefined Steinert LIBS sorting specification requirements, while, for the 5xxx series Mg concentration was a critical threshold. In contrast, effective enrichment of 7xxx series alloys remain challenging due to limited supply and systematic underestimation of Zn content. The findings indicate that Steinert LIBS is a viable and scalable technology for enabling closed-loop recycling of high-value aluminum alloys, supporting circular economy principles and sustainability objectives in the automotive industry.