RECOVERY OF URANIUM FROM SEAWATER .15. DEVELOPMENT OF AMIDOXIME RESINS WITH HIGH SEDIMENTATION-VELOCITY FOR PASSIVELY DRIVER FLUIDIZED-BED ADSORBERS

In order to design the amidoxime resins (RNH) suitable for circulating fluidized bed adsorbers, RNH were prepared from precursory acrylonitr ile-divinylbenzene copolymer beads of different particle sizes, and ch emical and physical properties of the resulting RNH were evaluated. Sp ecific surface areas, pore structures, swelling ratios, and anion- and cation-exchange capacities of RNH are little affected by the particle size, while their sedimentation velocities in water increase with an increase in particle size as expected from fluid dynamics. Although th e uptake of uncomplexed uranyl ion from a uranyl nitrate solution (0.0 1 M) was not influenced by the particle size, the uranium uptake from seawater decreases with an increase in the particle size, indicating t hat the particle diffusion of the bulky complexed species UO2 (CO3)34- essentially controls the overall adsorption rate in the recovery of u ranium from seawater.