Development of Sorbers for the Recovery of Uranium from Seawater. 1. Assessment of Key Parameters and Screening Studies of Sorber Materials

Abstract

At an average uranium content of' 3.3 ppb the oceans can be considered as a very low-grade but practically unlimited source of uranium. Some essential chemical aspects of a large-scale sorptive recovery of uranium from seawater are discussed with special emphasis on required sorber properties such as high physical and chemical stability in seawater, fast and selective uptake of uranium, as well as a sufficient loading capacity. Systematic screening tests, including about 200 sorber materials on the basis of organic ion-exchange resins, identified cross-linked poly(acry1amidoximes) as the most promising candidate sorbers. Their uranium uptake closely approaches the uranium content of actually explored uranium ores.

Recent International R&D Activities in the Extraction of Uranium from Seawater

“…Research activities on the extraction of uranium from seawater from a number of European countries are reported in the literature, including Finland (35), France (36-39), Germany (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58), Greece (59), Italy (60-64), Poland (65), Sweden, and UK (1,(66)(67)(68)(69)(70)(71). Among the European countries, Germany by far has the largest number of publications and patents on this subject.…”

“…The uranium loading on ploy(acrylamidoximes) ranged from hundreds to 3000 ppm, which roughly equals to the uranium content of actually explored uranium ores, while most of other materials tested had the uranium loading in the range of a few ppm. Besides, the cross-linked poly(acrylamidoximes) materials were found to have desired properties such as high physical and chemical stability in seawater, as well as fast and selective uptake of uranium (52,53).…”

Extraction of uranium from seawater : design and testing of a symbiotic system

“…-4 in very low concentrations of about 3.3 µg/L (Davies et al, 1964;Scanlan, 1977;Schenk et al, 1982) in the presence of relatively high concentrations of other ions, such as sodium, potassium, calcium, and some transitional metal ions (Davies et al, 1964;Scanlan, 1977;Schenk et al, 1982;Choppin, 1989). Owens et al (2011) -4 , considered to likely be the rate limiting step (Das et al, 2008(Das et al, , 2009.…”

“…Fortunately, uranium is present in the ocean as uranyl ions at a low concentration of 3-3.3µg/L (Scanlan, 1977;Schenk et al, 1982), which over the total volume of the oceans amounts to approximately 4.5 billion tonnes of uranium -nearly a thousand times that of conventional terrestrial reserves (Tamada, 2009). Finding a sustainable way to harvest uranium from seawater will provide a source of uranium for generations to come.…”

Recovery of Uranium from Seawater: Preparation and Development of Polymer-Supported Extractants

“…5,6 The polymer is often prepared by grafting acrylonitrile to polypropylene fibers and subsequent conversion of the nitrile to amidoxime. It provides the benchmark for loading capacity from seawater, often cited as 4 mg U/g polymer .…”