Pacific Northwest National Laboratory has been awarded two grants to develop new and inexpensive ways to extract valuable metals from the salty liquid that's the byproduct of geothermal energy production.
The grants, totaling $1.2 million, were among 32 awarded this week by the Geothermal Technologies Office within the Department of Energy's Office of Energy Efficiency and Renewable Energy.
"Investments in leading-edge geothermal technologies are diversifying our nation's energy portfolio today and could help power our low-carbon future tomorrow," said Doug Hollett, director of the Geothermal Technologies Office.
Among the metals PNNL will focus on are rare earth metals, which are used in many modern electronic devices, including electric vehicle motors and LED lights. But rare earth metals, such as europium and neodymium, are in limited supply and are often found in unstable parts of the world.
Developing sources of rare earth metals in the United States that are sustainable and inexpensive can help America manufacture more of its own clean technologies, according to PNNL.
In one project, a team led by PNNL will develop nanoparticles with a magnetic core and a nanomaterial shell that bonds with rare earth metals to remove them from geothermal brine.
PNNL will evaluate two different nanomaterial shells, one made of silica and another made of metal organic frameworks, also known as MOFs.
Rare earth metals could be produced at half the current production costs, according to PNNL. Initial calculations show more than 90 percent of the rare earth elements dissolved in geothermal brine could be extracted.
The grant makes $551,000 available for the research.
In the second project, a team led by PNNL will harvest not only rare earth metals, but also explore collecting trace levels of other valuable metals from geothermal brine.
PNNL will develop a solid material that captures the metals from brine, much like water softeners remove minerals from water.
PNNL will evaluate a wide range of materials, including ceramic, metal oxide, composite and polymer-based sorbents.
These materials could attract rare earth and other metals 10 to 1,000 times better than the industrial separation materials commonly used now, according to PNNL. The grant makes $650,000 available for research.