Rare earth manufacturers have tended to be based in China, but with defence technologies, alloys, optical equipment, heavy magnets for EVs and many more applications dependent on these elements, the west has become increasingly aware that it needs to develop its own production facilities and supply chain - particularly in light of the recent China US trade wars.
REEgen, a sustainable rare earth start-up based in Ithaca, New York, is well placed to help bring the US up to speed. The company, cofounded by CEO Alexa Schmitz and CTO Sean Medin, uses synthetic biology to solve environmental issues caused by rare earth mining. It was founded in February 2022 and spun out of Cornell University.
As a post-doc in the lab of Dr Buz Barstow, Schmitz focused on identifying the genetic elements of a bacteria called Gluconobacter oxydans which enables the leaching of rare-earths. During her research, she found that she could engineer the microbe to increase the rare-earth bioleaching process threefold by targeting a series of genes to construct powerful recombinant strains.
Medin, also originally a researcher at Cornell University as a PhD student in the Barstow Lab, looked at how bacteria naturally interacts and binds with rare-earth metals. His work looked at ways of engineering and selecting microbes that would bind to certain metals with higher affinities than others. This binding characteristic can effectively be used as a mineral separation mechanism to enhance the selection of certain metals out of the surrounding solution.
The boost in fermentation combined with the binding and leaching process seemed to make the duo's combined work a commercial opportunity, particularly given the trade situation with rare earths.
Although there are many mining companies popping up in the US and even Europe that are scouting for rare earth minerals, most aren't yet ready to start producing - this is where REEgen can help. Although the company can work with these mines to help provide clean tech for their flow sheets; a core element of their work, and one that is clearly close to Schmitz's heart, is the ability to retrieve rare earths from waste material produced by other companies. Coal ash, spent petroleum catalysts, and mine tailings are just some of the waste products containing rare earth metals. In addition to these industrial outlets that produce these products, REEgen is in talks with electronics and metal recycling companies to figure out where the rare earths might be recovered from existing material streams. One, a metal recycling smelter, forms an oxidised byproduct (slag) in its furnace that is high in rare earths. The company has to skim off and dispose of this slag. "Our removing and using this material as our feedstock, is a win-win for everyone," Schmitz says. "We like to think of ourselves as urban miners - we access minerals that are already out of the ground."
The non-toxic nature of the product is another selling point. The bacteria is the sort used in kombucha and is so non-toxic that a person could "stick their hand in the tank," Schmitz explains. This compares with traditional leaching chemicals, such as sulphuric or hydrochloric acid which are considered hazardous and can create impossible challenges in some work places. REEgen can therefore work with companies that would not be open to conventional leaching processes.
Unsurprisingly, given its sustainable credentials, REEgen is also focused on promoting a circular economy and industrial symbiosis - where the normally discarded byproducts of one industry feed into another. The company can also use the same processes to recover other critical metals such as lithium or nickel from waste, thereby offsetting the need for more extraction. In addition, the solids remaining after REEgen extracts the metals from slag can be used in concrete by builders. Normally the slags can't be used for this purpose because of their heavy metal content, but with the metals removed, REEgen's solid byproduct will be much safer for construction.
REEgen has a very clear road map to commercialisation. It already received Phase 1 Small Business Innovation and Research (SBIR) funding of $275k from the National Science Foundation in August 2023 and is waiting on final word for their phase 2 grant of $1.25m. The company will use the funds to design and construct a compact, low intensity unit which can be co-located with slag production at a smelter. It can tap directly in the partner company's plant and process their slag. REEgen aims to have this designed within the next three months, and a pilot unit constructed by the end of this year.
REEgen expects to install its first full-scale commercial unit by the end of 2026 and do a test run in early 2027. This unit will cost less than $1m to build and yield up to $5m in critical metals products per year at full capacity.
In addition, the company has several customers interested in buying rare earths and is already sending them samples. "Within the next 12 to 18 months we expect to start selling hundreds of tons of these products per year," Schmitz says.