Researchers at Michigan Technological University are using century-old mining techniques to recycle lithium-ion batteries at low cost. It helps that Lei Pan, an assistant professor of chemical engineering, has a graduate degree in mining engineering. Pan had a suspicion the techniques used in the mining industry 100 years ago to separate metal from ore might work for recycling batteries today, so he suggested his engineering students pursue that line of inquiry.
As so often happens in basic research, the process involved plenty of late hours and dead ends. “My mind goes back to the beginning, when nothing was working,” says Trevyn Payne, a chemical engineering senior. “A lot of times it was, honestly, ‘Let’s just try this.’ Sometimes when things worked out, it was kind of an accident.” Another senior, Zachary Oldenburg gave an example to Michigan Tech.
“We were trying all kinds of solvents to liberate chemicals, and after hours and hours, we found out that plain water worked the best.”
The team used tried and true mining industry techniques to separate everything in the battery — the casing, metal foils, the anode and cathode, and the lithium-metal oxide that is the most valuable component. Those basic components and materials can be used to make new batteries. “The biggest advantage of our process is that it’s inexpensive and energy efficient,” says student Ruitang Zhan. “For the purpose of remanufacturing, our recycled materials are as good as virgin materials, and they are cheaper,” Oldenburg adds.
“We saw the opportunity to use existing technology to address emerging challenges,” Pan says. “We use standard gravity separations to separate copper from aluminum, and we use froth flotation to recover critical materials, including graphite, lithium and cobalt. These mining technologies are the cheapest available, and the infrastructure to implement them already exists.”
The team presented their results at the People, Prosperity and the Planet competition last April in Washington, DC, where their work came to the attention of representatives of the EPA who wondered aloud why no one else was recycling batteries the same way. “Because no one else had a project leader who’s a mining engineer,” Zachary Oldenburg told them. The research was published recently in the journal Sustainable Materials and Technologies.
Battery recycling is in its infancy at the moment but will become a critical part of the transition to zero emissions vehicles as more and more electric cars take to the road. The low cost, low energy process created by Pan and his team could become solve one of the thorniest problems involving electric cars — what to do with lithium-ion batteries when they reach the end of their useful life.
Source: Clean Technica