Application of radiation grafting: progress and status of the extraction of uranium from seawater in Japan

Radiation grafting has been widely used in the preparation of new materials, including the use of radiation-induced grafting to incorporate special functional groups onto base materials for separations of metal elements. Since the late 1980's, research has been conducted in Japan to prepare sorbents with amidoxime groups for the extraction of uranium from seawater. A sorption efficiency of 1.5 g/kg was achieved in large-scale marine tests that lasted for 30 days. Preliminary cost evaluation conducted in Japan indicates that uranium in seawater could be collected with this technology at a price that is approximately 2-3 times the market spot price of uranium. The cost of extraction could be further reduced by optimizing the preparation of the sorbents, increasing the sorption capacity and selectivity, and improving the chemical and mechanical stability of the sorbents, making the technology of the extraction of uranium from seawater more competitive and attractive. As an example of the application of radiation grafting, this paper briefly introduces the research progress and status on the extraction of uranium from seawater in Japan. Recommendations on further research and development in this field are also discussed. (authors)