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Like some kind of modern-day alchemy, scientists have found a way to extract yellowcake uranium from seawater.
Yellowcake is the refined powered form of uranium ore. After it's been enriched, it can be used to produce fuel for nuclear power reactors. With further processing and enrichment, it can also be made into weapons-grade uranium too.
Until very recently, you could only get your hands on this stuff by mining uranium from the earth. Now, scientists have announced the development of a method that can draw yellowcake out of seawater using a low-cost modified yarn.
"This is a significant milestone," Gary Gill, a researcher at Pacific Northwest National Laboratory (PNNL), said in a statement. "It indicates that this approach can eventually provide commercially attractive nuclear fuel derived from the oceans — the largest source of uranium on earth."
Seawater naturally contains about three parts per billion of uranium. The newly developed acrylic fiber attracts and holds on to dissolved uranium naturally found in the water. You can watch part of this process in the video player below.
“We have chemically modified regular, inexpensive yarn, to convert it into an adsorbent which is selective for uranium, efficient and reusable," added Chien Wai, president of the Supercritical Technologies at LCW, an Idaho-based clean energy company.
Gill continued, "For each test, we put about two pounds of the fiber into the tank for about one month and pumped the seawater through quickly, to mimic conditions in the open ocean. LCW then extracted the uranium from the adsorbent and, from these first three tests, we got about five grams — about what a nickel weighs. It might not sound like much, but it can really add up."
This new project has been no small feat. It has been seven years in the works and cost roughly $25 million to complete. The US, Japan, and China have all been competing to master this feat for several years, but it finally looks like the US beat them to punch. The next step in the challenge is to scale-up their technique. The lab is currently applying for some further funding to test out this new uranium extraction out in the field in the Gulf of Mexico.
Unlike uranium mined from the ground, the amount of uranium in seawater is virtually inexhaustible. Forbes has previously estimated it could fuel a thousand 1,000-MW nuclear power plants for 100,000 years. Equally, conventional uranium mining is riddled with a whole load of political, social, and environmental controversies. For one, miners have been shown to suffer from higher rates of lung cancer. It can also contaminate groundwater and surface water with uranium by leaching processes.
The next step is to test out this extraction process in the warm waters of the Gulf of Mexico, where due to the temperature, extraction rates are expected to be three to five times higher. This, the researchers hope, will show that obtaining uranium from seawater is a viable, economical option.
