ENHANCING SORTING, CREATING VALUE

Diran Apelian, PhD, Alcoa-Howmet Professor of Mechanical Engineering and founding director of WPI’s Metal Processing Institute, has long focused his research on increasing recovery rates for aluminum from vehicles, a project un­dertaken through the Center for Resource Recovery and Recycling (CR3) and with support from Alcoa, the global metals and materials manufacturing giant. Modern vehicles contain up to 500 pounds of aluminum. And while more than 90 percent of that is reclaimed, there is good reason to try to do better, Apelian says. Recycling aluminum uses 95 percent less energy and produces 95 percent less carbon dioxide than making aluminum from bauxite ore. In addition, each ton of aluminum made from ore produces three tons of “red mud,” an extremely hazardous and alkaline sludge that has to be pumped into holding ponds to avoid contaminating other resources.

Recycling aluminum uses 95 percent less energy and produces 95 percent less carbon dioxide than making aluminum from bauxite ore.

Vehicle recyclers remove ferrous metals from junked cars with magnets. The nonferrous leftovers, typically treated as scrap, contain valuable minerals and metals, including up to 300 aluminum alloys that can be further separated, recovered, and reused — if technologies can be developed that make those efforts economical. “If I can separate that nonferrous part into its components, whereby I know what it is, definitely, I can remelt it and reuse it, and that’s where the value comes from,” Apelian says.

To achieve that enhanced sorting and separation, Apelian and his lab have developed chemistry-based tech­nologies, such as laser-induced breakdown spectroscopy and X-ray fluorescence, which can provide a precise analysis of the various alloys and other materials in the scrap passing by on a conveyor belt. “There are some very sophisticated ways in which we can create value from scrap just by knowing what is in it and separating it accordingly,” he says.

Starting with support from CR3, the project was able to win a $3 million award from the U.S. Energy Department’s Advanced Research Projects Agency-Energy to develop a scrap sorting and aluminum recovery factory. “We want to have a 100 percent recyclability,” Apelian says. “Why not? It’s doable.”