Bipolar Uranium Extraction From Seawater With Ultra-Low Cell Voltage

June 11, 2025 by Maya Posch 51 Comments

As common as uranium is in the ground around us, the world’s oceans contain a thousand times more uranium (~4.5 billion tons) than can be mined today. This makes extracting uranium as well as other resources from seawater a very interesting proposition, albeit it one that requires finding a technological solution to not only filter out these highly diluted substances, but also do so in a way that’s economically viable. Now it seems that Chinese researchers have recently come tantalizingly close to achieving this goal.

The anode chemical reaction to extract uranium. (Credit: Wang et al., Nature Sustainability, 2025)

The used electrochemical method is described in the paper (gift link) by [Yanjing Wang] et al., as published in Nature Sustainability. The claimed recovery cost of up to 100% of the uranium in the seawater is approximately $83/kilogram, which would be much cheaper than previous methods and is within striking distance of current uranium spot prices at about $70 – 85.

Of course, the challenge is to scale up this lab-sized prototype into something more industrial-sized. What’s interesting about this low-voltage method is that the conversion of uranium oxide ions to solid uranium oxides occurs at both the anode and cathode unlike with previous electrochemical methods. The copper anode becomes part of the electrochemical process, with UO₂ deposited on the cathode and U₃O₈ on the anode.

Among the reported performance statistics of this prototype are the ability to extract UO₂²⁺ ions from an NaCl solution at concentrations ranging from 1 – 50 ppm. At 20 ppm and in the presence of Cl^– ions (as is typical in seawater), the extraction rate was about 100%, compared to ~9.1% for the adsorption method. All of this required only a cell voltage of 0.6 V with 50 mA current, while being highly uranium-selective. Copper pollution of the water is also prevented, as the dissolved copper from the anode was found on the cathode after testing.

The process was tested on actual seawater (East & South China Sea), with ten hours of operation resulting in a recovery rate of 100% and 85.3% respectively. With potential electrode optimizations suggested by the authors, this extraction method might prove to be a viable way to not only recover uranium from seawater, but also at uranium mining facilities and more.

Optimizing The Mining Of Uranium From Coal Ash And Seawater

August 23, 2022 by Maya Posch 55 Comments

Of all the elements that make up the Earth’s crust, uranium is reasonably abundant, coming in at 49th place, ahead of elements such as tin, tungsten and silver. Ever since humankind began to exploit uranium for its fissile properties in energy production, this abundance has also translated into widespread availability for mining. As of 2019, Kazakhstan, Canada and Australia formed the world’s main producers, accounting for about 68% of output.

Considering the enormous energy density of uranium when used as fuel in a nuclear fission reactor, the demand for uranium is relatively low, especially combined with the long (two years on average) refueling cycles of commercial reactors. The effect is that even with the very inefficient once-through fuel cycle – which only uses a fraction of the uranium fuel’s potential energy – uranium market prices have remained relatively low and stable even amidst geopolitical crises.

Despite this, the gradual rise in uranium market prices ($10/lb in 2003, $49/lb in 2022), as well as the rapid construction of new reactors is driving new exploration. Here recent innovations may make uranium fuel even more accessible to all nations, by unlocking the billions of tons of uranium found in plain seawater as well as the many tons of fly ash produced by coal plants every single day.

Continue reading “Optimizing The Mining Of Uranium From Coal Ash And Seawater” →