The metal components inside our electronics are valuable, somewhere around $25,000 per ton, but difficult and expensive to recycle.
If E-waste is recycled, it’s usually smelted, melting away the plastic and ceramic to leave behind the recoverable metals. Smelting e-waste is not done in the United States because it uses a lot of energy and produces a huge amount of emissions; permitting and mitigation alone make it too costly.
“We're basically just offshoring our waste at this point,” said Tedd Lister. He’s a research scientist at Idaho National Laboratory (INL).
About a decade ago, Lister surmised that electrochemistry, or triggering a reaction between elements with electricity,might be able to extract the valuable metals in e-waste without the fossil fuels and emissions of smelting.
The first step is grinding e-waste down into a coarse powder, something about the texture of Panko bread crumbs.
“It's really hard to go after the precious metals in one step because all these other metals that are easier to dissolve are in the way,” Lister explained. “And so any kind of hydromet process really has to react to all the copper in getting to the gold.”
By applying electric current, the process dubbed E-RECOV (Electrochemical Recycling Electronic Constituents of Value) can reuse the chemical mixture over and over again to do the job in multiple steps.
“The efficiency of the process is approximately 90-100%, meaning that the electrons that are put in are doing the job that we want them to do,” Lister explained.
Luis Diaz is an electrochemical engineer at INL. He’s been working on the project for about seven years.
“We can actually reduce over 80% of the total associated emissions of equivalent CO2 versus traditional hydrometallurgical processes,” he said. “There are chemicals in there. There is acid. Of course, you have the smell of acid, but it's not strong. You don't have a lot of gaseous emissions.”
A tabletop prototype developed at INL capable of processing up to 2 pounds a day of e-waste was scaled up by an Ohio company last year, to about the size of an SUV.
Diaz said one of the concerns was the potential the process could generate chlorine gas, which did not happen.
Another challenge as the project was being scaled up was ensuring that the flow of chemicals through electrochemical cells didn’t start defaulting to a preferred path, called channeling, which could throw the entire reaction out of balance.
“That's what was important in the first test that we did back in Ohio,” Diaz said. “Seeing that the electrolyzer was working without having these hydrodynamic issues.”
Lister said it was just the second time in his career a project he helped develop at ‘bench scale’ has come this close to commercial viability.
“At the same time you realize that you just made a big step, but you are not at the finish line yet,” Lister said. “Now the challenge is that the system has to demonstrate that it can operate continuously and as we expect.”
The research was funded initially by the US Department of Energy’s Critical Minerals Institute. Subsequent funding has come from the federal government’s Small Business Innovation and Research grant program.
The next step will be taken by a California company called Quantum Ventura. They will try to scale up the latest model by three or four times to be suitable for an industrial-scale facility and have applied for additional SBIR funding to do it.
While the science appears to be successful at scale, the final test, Lister said, always involves economic factors like the business of collecting e-waste and then finding a market for the recovered product. He thinks there could be a commercially viable unit as early as five years from now.
“The question is: can someone engineer it and scale it? And you have to not only have a good idea, you always have to have someone that puts money behind it. And will that occur? I just don't know,” Lister said.
But he’s optimistic.
