Alcoa’s ASTRAEA™ process converts post-consumer scrap into high purity aluminum

Alcoa is developing a process that can convert low-quality aluminum scrap to quality levels far exceeding the purity levels at commercial smelters, potentially tapping vast supplies of unused aluminum scrap.

Alcoa’s ASTRAEA^TM process is a proprietary technology that can purify any aluminum scrap to such high levels that it has the potential to create an entirely new value chain. The ASTRAEA process is one of the items contained in Alcoa’s technology roadmap, which includes items that will help the Company reach its vision to reinvent the aluminum industry for a sustainable future.

Today, most smelters produce what is known as commodity grade metal, or P1020. That designation represents 0.1% silicon and 0.2% iron. With few exceptions, most smelters have the technical capability to produce up to P0404, depending on how they deploy technology. The market has two, currently available solutions, that can translate P0610 or P1020 into higher grades.

However, Alcoa’s ASTRAEA process would build a robust solution that could take any post-consumer aluminum scrap, regardless of alloy combination, and beneficiate it up to P0101. This super-pure metal could then be blended with less pure scrap to produce a metal that meets purity thresholds, vastly improving the supply of post-consumer scrap that can be used as a raw material. The purity would be high enough for most rolling mill and extrusion applications, including applications in aerospace.

Alcoa’s initial source material for this technology is Zorba, which is auto shred aluminum scrap. Because the industry is unable to remove trace metals from this scrap, much of this metal is used to make engine blocks for gas-powered cars, which can tolerate less-pure scrap as a raw material. However, that market is slowly diminishing due to the growth of electric vehicles, which require higher-purity aluminum for engines and other componentry. Remaining Zorba supply is shipped to Asia in vast quantities. The U.S. alone produces approximately 4 million tons of Zorba annually, approximately 1.3 Mmt of which is shipped to Asia.

According to the International Aluminium Institute (IAI), the industry needs to increase post-consumer scrap recycling by 55 percent over 2018 levels by 2030 to achieve industry decarbonization goals for the 1.5-degree scenario outlined in the Paris Agreement. Alcoa’s patented technology could help achieve those scrap recycling targets.

Learn more: Alcoa Virtual Investor Day 2021 - Ben Kahrs, Executive Vice President and Chief Innovation Officer (Registration required)