Consumer electronics constitute a rapidly increasing source of waste. Cell phones, tablets and the like are typically made of non-renewable, non-biodegradable, partly environmentally toxic materials. A report from United Nations University (UNU) found that the world produced 41.8 million metric tons of e-waste in 2014 – an amount that would fill 1.15 million 18-wheel trucks. Lined up, those trucks would stretch from New York to Tokyo and back. The Environmental Protection Agency estimates that only 15-20% of e-waste is recycled, the rest of these electronics go directly into landfills and incinerators.
The world produces close to 50 million tonnes of e-waste every year as consumers and businesses throw out their old smartphones, computers and household appliances – material worth an estimated $62.5 billion (EUR 55 billion or roughly Rs. 4,40,000 crores). Only a small percentage of the refuse, which contains valuable and reusable materials such as metals and rare earth elements vital for electronics, is ever recycled.
Contemporary approaches such as pyrometallurgy and hydrometallurgy for recovering critical elements from e-waste are best suited to recover a large volume fraction component from the feedstock and are ill-suited to recover multiple low-volume fraction elements typically found in e-waste. While it is theoretically possible to exploit a combination of physical, chemical, and functional properties for fractional recovery of critical elements, such approaches are limited by insufficient knowledge on chemistries that can work together at the point of disposal.
The U.S. currently depends on countries like China to provide raw materials that are essential to electronics enabling its national defense. But according to Musho, that “reliance on foreign national resources has led to the White House identifying a critical shortage in the semiconductor supply chain.”
Musho said that shortage is one reason the DOD is eyeing readily available electronic waste like old “LEDs and microelectronic circuits used for amplifying radio frequencies, which contain critical supply chain materials.”
Recycling at the Point of Disposal (RPOD) Disruption Opportunity (DO)
In June 2022, DARPA launched Recycling at the Point of Disposal (RPOD) Disruption Opportunity (DO) will evaluate the technical feasibility to recover (separate and coextract) multiple low-volume fraction critical elements present in end-of-life electronic hardware (e-waste). Separation is defined as the extraction of various elements sequentially, and coextraction is defined as the extraction of a specified list of elements simultaneously from a feedstock containing a mixture of elements with other constituents.
DARPA’s Recycling at the Point of Disposal (RPOD) program aims to
- develop novel extraction chemistries and explore practical limits of yield, extraction efficiency, and purity to recover a selective list of critical elements from commercial and DoD e-waste, and
- demonstrate the technology in a benchtop hardware prototype.
“Contemporary techniques for the recovery of materials from e-waste have been built around extracting one or two elements,” said Vishnu Sundaresan, RPOD program manager in DARPA’s Defense Sciences Office. “The elements identified as critical due to vulnerabilities in their supply chain are typically at a very small volume fraction – approximately 0.1% – 5% – and contemporary techniques are ill-suited for their recovery. RPOD will evaluate the feasibility of extracting up to seven low-volume fraction elements that would otherwise be lost as process waste in contemporary recovery techniques. RPOD performer teams are evaluating orthogonal approaches that have the potential to extract critical elements at a fraction of the energy compared to today’s techniques without the generation of toxic liquid or gaseous byproducts. We are looking forward to working with the performers and the Defense Logistics Agency to develop practically viable extraction technologies for DoD’s use.”
If successful, the recovered stream from e-waste can minimize supply chain disruptions of critical elements sourced or processed abroad that are essential for high performance DoD hardware.
DARPA has selected multiple teams of university researchers for the Recycling at the Point of Disposal (RPOD) program. RPOD will evaluate the technical feasibility of recovering multiple low-volume fraction critical elements present in end-of-life electronics hardware (e-waste). The program seeks to develop small-footprint platforms with greatly reduced energy consumption and waste generation in the extraction process.
The teams will develop novel extraction chemistries and explore practical limits of yield, extraction efficiency, and purity to recover a selective list of critical elements from a feedstock representative of commercial and Department of Defense (DoD) e-waste. The technology for both separation and coextraction of critical elements will ultimately be demonstrated in a benchtop hardware prototype.
The selected teams include Arizona State University, Iowa State University, and Massachusetts Institute of Technology with the following approaches:
- Arizona State University, teamed with TG Companies LLC, will develop an improved hydrometallurgical process based on a combination of selective leaching and electrowinning. Using a regenerative process, their approach aims to reduce the number of chemicals and associated waste that results from traditional processes.
- Iowa State University will develop an innovative surface and interface engineering approach for driving alloy de-mixing to recover target materials of interest.
- Massachusetts Institute of Technology will utilize selectivity and specificity of forming sulfides from a mixture of elements. Using electrochemical reduction, they aim to recover high-purity, critical materials.
In addition to the above university teams, the National Institute of Standards and Technology will explore the feasibility of acoustic-electric force balance for a novel metrology technique and explore the applicability of this metrology technique for recovery of multiple critical elements.
The teams will first model their novel recovery technology concepts and process models to understand and define practical limits of yield as well as develop databases of supply chain webs (i.e., networks of recycling and manufacturing processes that can reuse co-extracted materials without separating them). At the end of the program, the teams will demonstrate proof-of-concept hardware for recovery of critical elements and estimate the associated energy budget to understand the feasibility of fielding this type of technology.
West Virginia University researchers are resurrecting discarded electronics,
Terence Musho, associate professor of mechanical and aerospace engineering at the Benjamin M. Statler College of Engineering and Mineral Resources, is leading the project, which received more than $250,000 from the Defense Advanced Research Projects Agency at the U.S. Department of Defense.
One key factor setting the research Musho is conducting with Statler Professor Edward Sabolskyapart from current systems for e-waste recycling is the “ability to achieve very high temperatures in a very rapid manner,” which allows their technology to be modular. That is, because it’s relatively small, it can easily be moved in modules from place to place.
Electronics recycling began to emerge in the 1970s but it has never gained much traction. Musho explained that when you take your old electronics to Best Buy, there are just a handful of facilities in the nation where the electronics can be processed. “Those places get a mountain of e-waste,” he said.
Electronics recycling facilities deal with that e-waste via a process of pyrometallurgy or hydrometallurgy. Both those processes use either high temperatures or hazardous chemicals to extract minerals from electronics and both need large quantities of waste in order to be economical.
Largely because of problems like those, most current e-waste heads to landfills. In its effort to change that, the DOD has focused on recovering seven specific elements from e-waste, chief among them gallium, indium and tantalum.
Musho will guide their experiments, using computational thermodynamics to simulate the mineral recovery process. Sabolsky will validate the simulations to prove the process works in practice.
Musho is confident that it will work, especially because Sabolsky’s previous research laid the groundwork for this study. “Ed did a previous study on coal fly ash, a waste product of coal-fired power plants, and he demonstrated that this process works for other critical elements present in fly ash. Now, we’ll take that knowledge, improve upon it and apply it to e-waste.”The project’s first phase is a nine-month study demonstrating Musho and Sabolsky’s e-waste recycling process in the lab.
After that, they’ll refine the approach to “hit tighter purity standards” for the recovered minerals. They’ll scale up to handle greater quantities of material and work on packaging the technology within a small, modular unit that’s easily transported, as they begin to consider commercialization.
“We have an abundance of critical materials currently sitting in e-waste in our landfills,” Musho said. “It’s just a matter of determining the best method to recover these elements. The technology we’re developing provides a supply chain solution not only for DOD electronics but also consumer electronics.”
“That means the DOD can transport this technology around to the point of disposal of these e-waste materials,” Musho said. “Space debris is an issue that’s gaining attention, so one potentially far-out idea is that this potentially could be used in space. You could collect junk satellites, recycle the waste and bring the raw materials back to earth.
“Another possible application would be U.S. Navy ships, which could move this equipment around to different ports for waste recycling.” The technology also has promise beyond the sphere of national defense. “You could have a point-of-disposal e-waste recycler in each community,” Musho suggested. “Communities could recycle their own e-waste, get the raw materials out and sell those materials back to manufacturers.”
If successful, the recovered stream from e-waste demonstrated by the technologies developed in RPOD can be scaled up to address supply chain disruptions of critical elements sourced or processed abroad that are essential for high performance DoD hardware.
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