Researchers study methods to extract rare earths and platinum group metals from ocean biomass.
Amid rising demand for critical minerals for fields like renewable energy and electric vehicles, countries worldwide are looking for new sources of supply. Three projects funded by the Advanced Research Projects Agency-Energy or ARPA-E are now studying methods to extract rare earth elements (REEs) and platinum group metals (PGMs) from different types of oceanic biomass, such as algae and seaweed (PDF). Both groups of critical minerals are essential ingredients in advanced technologies and clean energy fields. While REEs are contents of permanent magnets used in offshore wind turbines and motors of electric vehicles, for example, PGMs are used as electrolyzers in hydrogen production.
Macroalgae as Biological Ore
The first research team, led by Pacific Northwest National Laboratory (PNNL), plans to study techniques to harvest REEs and PGMs from what they call “biological ore,” or species of marine macroalgae. The researchers leverage algae’s hyperaccumulating nature, which enables them to grow quickly and in soil or water with high concentrations of metals, allowing for a constant stream of feedstock. The team plans to combine the exploration of macroalgae as a critical mineral crop with existing PNNL research on using algae as a source of biofuel, where it aims to optimize the cost of producing bioenergy from algae-based feedstocks.
Studying the Accumulation of Rare Earths in Seaweed
The second research team, led by the University of Alaska Fairbanks, will analyze a different hyperaccumulating species: seaweed, around the Bokan Mountain rare earth element deposit in Southeast Alaska. The scientists will examine how much of the critical minerals are accumulated in the seaweed and whether they can be harvested in an environmentally friendly fashion. According to the lead researcher, Schery Umanzor, even high accumulations would only yield a few metals per ton of seaweed. Still, if viable, Umanzor added, seaweed could be a low-impact alternative to traditional mining.
Incorporating Critical Mineral Extraction Into Sustainable Food Processing
The third ARPA-E-funded project, led by food technology startup Umaro Foods, will study methods to extract REEs and PGMs from algae, like the PNNL-led team. While PNNL combines biofuel research with critical mineral extraction, Umaro specializes in creating edible food from algae, like bacon. The startup will study ways to incorporate the extraction of REEs and PGMs into existing food processing streams by using chelator molecules that bind to the metals.
ARPA-E announced the opening of applications for funding for studying critical mineral extraction from oceanic biomass earlier this year to advance technologies that are too early in development for private-sector investment. The total amount of financing is set at $5 million.