Panel: Better Tech Can Make Recycled Aluminum More Desirable
Sustainability experts said the difference between suppliers’ desired alloy mix and what is currently in the scrap stream is an obstacle to creating a closed-loop recycling system.
A panel of metal-recycling experts said the biggest challenge facing the recycling industry is that the composition of materials coming from the stream of scrapped vehicles does not match the composition of materials sought by automotive suppliers.
The panel was part of the Aluminum Transportation Group’s annual Aluminum Tech Forum, which SAE Media attended in Detroit.
Daniel Cooper, an assistant professor in mechanical engineering at the University of Michigan, said part of that difference is a by-product of “imperfect” liberation and separation of different metals. “You have contamination with foreign materials, some iron and copper getting into your aluminum stream – that could be from, say, steel rivets that are holding your aluminum sheet together, copper wiring from all the electronics going into vehicles. And then also you just have alloy-mixing differences.”
He said another difference is that the scrap stream of today consists of the vehicle supply of 20 years ago, making it entirely different from materials employed in current lightweight components and vehicles.
Cooper suggested there are three chief solutions:
- “There are emerging technologies ─ for example, laser-induced breakdown spectroscopy, that's one of the most successful technologies which now is seeing industrial application and can separate the alloy family and, in some cases, even the alloy level,” he said. Though the process is slower, he said some customers could be willing to pay for the better-separated material.
- Suppliers can adopt new alloy specifications that can incorporate more recycled content that is “a little more tolerant of some of the higher residuals,” such as allowing more copper than current alloys.
- OEMs can design vehicles differently to allow for better separation of materials at the end of a vehicle’s life. He said the Aluminum Association and the Department of Energy are doing research in this area.
Another available technology, among many, is using x-rays to distinguish between densities, said Emily Volstad, CEO of Massachusetts-based VALIS, which creates software for scrap processors. That “can separate based on density so you can create the heavy non-ferrous package with your copper alloys, zinc alloys, and then what you have remaining from that is twitch (a mixture of shredded wrought and cast aluminum) that can then feed into” laser separation.
Volstad also mentioned the increasingly important role of AI in scrap sortation. “Especially,” she said, “AI-enhanced systems that use sensors to distinguish between metals. And all these different tools along the process are generating data” that can point to ways to increase efficiency while creating the desired product. The panel’s focus was on the future of closed-loop recycling. Regarding a common understanding of what that is, however, Chris Koffler, technical director for sustainability consulting with Boston-based Sphera, said that different people offer different definitions. “In the ISO standards that we work with, it’s defined as something being recycled back into the same product system. But there is ample debate of what constitutes the same product system. Is it like a can-to-can recycling? Is sheet-to-sheet recycling? Or does a sheet-to-extrusion recycling also qualify as closed-loop recycling? There is no, let's say, international agreement.”
The U of M’s Cooper, who leads his university’s Resourceful Manufacturing and Design Group (ReMaDe), said that definitions aren’t terribly important if the goal is the same: to maintain the value of the material to be as high as possible.
Koffler emphasized a need for everyone to keep an eye out for an important semantic distinction. “We hear the word recyclability. Today, in terms of calculating carbon footprints, that's really not relevant. What's relevant is what actually happens with the scrap. Just because something is recyclable doesn't mean it is actually being recycled.” He cited aluminum cans and their 49% recycling rate as an example.
Cooper said that the industry already is good at collecting the scrap from vehicles, and that if the new technologies make for pricier recycled aluminum, it could encourage recyclers to, for instance, recycle a higher percentage of aluminum cans. “Scrap collection does have an elasticity with price,” he said.
Addressing what can be done to encourage more recycling and educate consumers and governments about the industry, Koffler mentioned the need for policy that encourages actual progress. He cited the European Union’s end-of-life vehicle directive. “A lot of the focus was about heavy metal contents and phasing those out,” he said. “But when you introduce a vehicle into the market, you also have to show that – I think by now – it's 95 percent recyclable. But again, that's recyclable, it doesn't mean it's actually recycled. So, to me, that's not very meaningful metric.”
The panel was moderated by Travis Carr, sales director for Real Alloy in Tulsa, Oklahoma.