Science

Oak Ridge develops improved way of extracting uranium from seawater

Oak Ridge develops improved wa...
A disc of highly enriched uranium from the Y-12 National Security Complex Plant
A disc of highly enriched uranium from the Y-12 National Security Complex Plant
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A disc of highly enriched uranium from the Y-12 National Security Complex Plant
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A disc of highly enriched uranium from the Y-12 National Security Complex Plant
A disc of highly enriched uranium from the Y-12 National Security Complex Plant
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A disc of highly enriched uranium from the Y-12 National Security Complex Plant

The world’s estimated reserves of uranium are only 6 million tons and with the growing demand for reliable energy free of greenhouse emissions leading to more and more nuclear plants being built, that supply may not last very long. Some estimates place the time before all the uranium is gone at between 50 and 200 years. However, the oceans of the world contain 4.5 billion tons of uranium dissolved in seawater. That’s enough to last something on the order of 6,500 years. The tricky bit is getting it out, but a team at Oak Ridge National Laboratory, Tennessee has come a step closer to economically extracting uranium from seawater with a new material that is much more efficient than previous methods.

Ever since it was learned how much precious metal is dissolved in seawater, scientists, engineers, visionaries and con men have dreamed of ways to extract it. In the 1920s, popular science editor Hugo Gernsback graced the covers of his magazines with fanciful floating factories hauling giant sheets of gold out of the briny deep. Since the 1960s, almost a dozen nations have studied ways of making the dream a reality. The Japanese have been particularly successful with the the Japan Atomic Energy Research Institute having some success in extracting uranium using mats of woven polymer fibers in 2002, but at a cost three times the market price of the metal at the time. That is the basic problem – you can get the metal out, but it costs more than it’s worth.

Now a team at Oak Ridge is working to bring down those costs by devising a more efficient method of extraction. The Oak Ridge team’s approach is based on their examination of how plastic and chemical groups are bound together. From this, they determined that it was possible to enhance the uranium-extracting characteristic of the uranium-loving amidoxime chemical groups in their high-capacity reusable adsorbent, which they combined with a Florida company's high-surface-area polyethylene fibers. These fibers have a small diameter with high surface areas and a variety of shapes. Tailoring the size and shape of the fibers increases their adsorption capacity. The fibers are bombarded with radiation, which react with chemicals that have a high affinity for particular metals. The result is a little uranium sponge.

Using the material, called Hicap, is simply a matter of immersing it in seawater. As it sits in the water, the material grabs on to the uranium ions and deposits them on the surface of its fibers. Once a sufficient amount of uranium is adsorbed, the material is removed and the metal extracted with acid. "We have shown that our adsorbents can extract five to seven times more uranium at uptake rates seven times faster than the world's best adsorbents," said Chris Janke, one of the inventors and a member of Oak Ridge’s Materials Science and Technology Division. HiCap is also reusable as, after the extraction process, it can be regenerated with potassium hydroxide.

The results of the Oak Ridge team were verified by researchers at Pacific Northwest National Laboratory’s Marine Sciences Laboratory in Sequim, Washington, and were presented a last Wednesday’s meeting of the American Chemical Society in Philadelphia. The material is a long way from making uranium as common as pig iron, but it does demonstrate that extracting it from the oceans may no longer be a con man’s dream.

Sources: Oak Ridge National Laboratory, Pacific Northwest National Laboratory

20 comments
Pikeman
With the Japanese method the price of uranium wold have to triple for the process to be commercially viable and this is better. But what is the ratio of isotopes? If it does not need as much enriching that would really alter the real price.
Bob Stuart
Nuclear power is not close to fossil-fuel free. Currently, it takes over a decade for a Nuke to pay back the power used to build and fuel it, and the future costs are looking even worse, as a tax on all our descendants.
JBar
1) ...and after that decade you have pure profit and no pollution. 2) as you remove the uranium from sea water, the remaining uranium is diluted making these processing costs increase every day. 2) current uranium reserves 250 years?? Post processing of existing waste stockpiles would last us 10,000 years alone. Please keep in mind that the amount of uranium actually consumed in nuclear power is only one gallon per 1 million Americans per year. That ratio is based on 100% nuclear power (no more coal, oil or natural gas!). The problem occures when we bury the spent fuel instead of post processing it to remove the still useable fuel. mbarbour65@hotmail.com.
BombR76
This is an exciting area of research to use the oceans to extract a variety of costly metals. However, it is expensive for uranium extraction to be viable in the short-term. I commend ORNL for their research. Currently, there are alternatives to mining uranium that 'mines' the spent fuel by either Plutonium and Uranium Recovery by EXtraction (PUREX), or the Mixed-OXide (MOX) processes. There are pools of spent nuclear fuel in the fuel rods at nuclear power plants waiting final disposition.
wle
no, the 'problem' is - - 'how to get all the water in all the oceans to go through your uranium filter' how much energy and time would THAT take? especially as the concentration dropped.. i assume you can;t divide the ocean into 2 sides: 'filtered' and 'unfiltered' wle
StWils
While this specific objective is commendable a version of this material that could be more broad spectrum and adsorb a range of radioactive isotopes could enable the Russians to detoxify the areas in the Barents and Arctic seas that have been poisoned by Soviet sub reactors as well as to clean up at least some of the real estate devastated around Chernobyl. It would important for Russia and Ukraine to reduce the excluded area around Chernobyl. It would be fantastic if estimates of abandoning this area declined from 10,000 years to maybe 50 along with a price tag that might be tolerable. After all, parts of Bimini Atoll are still too hot to enter or eat the fish from. It would be great if this kind of problem could go from being insurmountable to being merely a "superfund size problem".
PeteKK
We need to get away from the PBR and BWR reactors that use uranium and go with a safer and more cost effective way of producing electricity like LFTR. A technology that was already developed by Oak Ridge in the 1950's and abandoned because there wasn't enough profitability. It's time we move towards eco friendly solutions. Once again we're going in the wrong direction. It's time to stop lining the pockets of huge corporations and start giving back to the people and the planet.
see3d
Thorium is much more common and in a molton salt reactor is much more cost effective and burns nearly 100% of the fuel, so little waste. It is also disaster proof by design. Why are we still talking about Uranium for the future? Go green nukes!
TankThinker
I have to laugh every time I read posts by uranium "experts" saying how easy it is to do this or that or how we should just use thorium like every energy expert out there is a complete fool for not doing so! Come on, every option is carefully examined and if it is practical and the costs are less than other alternatives, it is used. Period. Maybe in 3-5 years (that's what every scientists says so they can get more funding yet less than 1% of the claims ever pan out to become a useful technology - devil is in the details) we will have this new method but for today the costs for uranium are going up and the reserves are going down and the concentrations are getting lower (more energy needed to extract the same amount of useful product = less net energy). It is still a non-renewable resource and is expected to peak in less than 20 years, at the current rate of use. Read that again - current rate of use. For those nuclear fanboys who want every country on Earth to build more nuclear plants, the more you build, the faster the resource is used up. Many forget this point because it hurts their position. Both the third and forth largest economies in the world (Japan and Germany) and arguably the two most technologically advanced are giving up on nuclear power. Completely. Think about that, forum experts. Why would they do that if the solutions were so cheap and simple? They wouldn't. The US would be building new plants and using thorium but they are not. Why? Because they already tried them! The costs were too high. The US can no longer afford to spend the crazy amounts of capital needed for new nuclear plants and technologies. The nuclear industry is near dead and it will stay that way. Now if these guys are right and they find a way to have almost unlimited fuel at competitive prices then maybe but don't count on it until the fuel is on the market at high volumes. Maybe in 10 years... Then add 10 - 20 more years to where the new reactors are build and we may just have good electricity prices. I am not crossing my fingers yet. I want proof and real cost data. Oh, finding a cost effective way to get rid of our spend waste would also need to be resolved. It isn't sustainable if you don't take care of the waste.
Synchro
Nobody has put any serious investment into Thorium, only a miniscule fraction of what's been invested in other nuclear solutions. Thorium also has a major 'disadvantage' in that it doesn't provide material for nuclear weapons, so there is no military or political incentive (and matching military-sized budget) to get the job done. Thorium is certainly promising but, despite many wildly optimistic claims, it's not 'done' by any stretch of the imagination and still requires enormous investment if it is to provide realistic amounts of power in the near term. Re: this article - if they can use it to extract Uranium, then they can use the same technique to extract Thorium (or any other metal), which is much more plentiful anyway.