PNNL researchers have for the first time created five grams of uranium yellowcake using acrylic fibers to extract it from seawater.
The yarn-like material was developed by PNNL’s co-partner LCW Supercritical Technologies.
“This is a significant milestone,” said PNNL researcher Gary Gill. “It indicates that this approach can eventually provide commercially attractive nuclear fuel derived from the oceans – the largest source of uranium on earth.”
It’s estimated that there is at least four billion tons of uranium in seawater, which is about 500 times the amount of uranium known to exist in land-based ores.
Chien Wai, founder and president of LCW Supercritical Technologies, worked out a new approach to adsorb the uranium onto a molecule or ligand that is chemically bound to the acrylic fiber.
The end result was a durable and reusable wavy-looking polymer adsorbent that can be deployed in a marine environment.
According to Wai, the adsorbent material is inexpensive and can be also created from waste yarn.
The adsorbent properties of the material are reversible, and the captured uranium is easily released to be processed into yellowcake.
An analysis of the same suggests it could be competitive with the cost of uranium produced through land-based mining.
PNNL researchers have conducted three separate tests of the adsorbent’s performance to date by exposing it to large volumes of seawater from Sequim Bay next to its Marine Sciences Laboratory. The water was pumped into a tank about the size of a large hot tub.
“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” said Gill. “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.”
Wai says the fibers could someday be used one day to clean up toxic waterways themselves.
Moreover, they could be used to extract vanadium, an expensive metal used in large scale batteries, from the oceans instead of mining it from the ground.
Image, video and content: LCW Supercritical Technologies/PNNL