New tool identifies alloys in the field, making sorting, re-use more efficient
November 2015 - Recycling bins for beverage cans, glass, plastic or paper are pretty easy to find. People can drop their used cans of soda, for example, in any number of receptacles located near shops, at home and at the office. Aside from beverage cans, however, aluminum recycling remains low among many industries. The effect of that rate up and down the supply chain is worth considering.
PARC, a Xerox company, received its “plus up” award from the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) after completing its original $1 million contract as part of ARPA-E’s Modern Electro/Thermochemical Advancements for Light-Metal Systems (METALS) program, geared toward developing cost-effective and energy efficient manufacturing techniques to process and recycle light metals.
Why the low recycling rate for aluminum? Jessy Rivest, who manages the energy materials and systems group in the Hardware Systems Laboratory at PARC, says the difficulty and expense of sorting one aluminum alloy from another is the main reason.
“For example, an aluminum alloy with 15 percent silicon has high fluidity for casting while an aluminum alloy with 6 percent zinc has very high strength,” explains Rivest. “If these two alloys are mixed together, the result is a blend that is neither castable nor strong.”
Those seeking to identify aluminum alloys in the field today use an XRF, a $40,000 spectroscopic tool that takes one to two minutes per sample and “has a hard time seeing low-atomic-weight alloy components such as silicon and magnesium.”
According to Rivest, PARC aims to make a tool ten to 100 times cheaper than the XRF, and which can identify material samples in seconds instead of minutes, including alloy classes with low-atomic-weight metals.
Sectors that stand to benefit
The automotive sector, which continues to increase the amount of aluminum used in vehicles to reduce weight and emissions, is PARC’s main focus, “though there is scrap aluminum from construction and appliances as well as pre-consumer (manufacturing floor) scrap.”
It’s in the manufacturing automotive parts, body panels, chassis struts, engine blocks and wheels where Rivest believes this technology will have the greatest initial impact. “When these cars [made with aluminum components] start hitting the junkyard … that scrap is sent to China for hand-sorting,” Rivest says. “There must be an automated technology in place to quickly and cheaply differentiate the aluminum alloys from each other.” MM