The extraction of uranium from nitrate solutions using a resin containing tributyl phosphate
Tributyl phosphate adsorbed on to the macroporous polystyrene divinyl benzene resin, Levextrel OC 1023, was used for the extraction of uranium from solutions of nitric acid and aluminium nitrate with a total nitrate concentration of 5.5 M. Uranium is strongly adsorbed from these solutions; the distribution coefficient increases with the concentration of aluminium nitrate. The equilibrium distribution is described by the Langmuir equation. The rate of adsorption of uranium was correlated by the conventional equation for mass transfer through the liquid film below 0.1 g U/L in solution. However, at higher values this was no longer valid and a modified version of this equation is proposed here which correlated all adsorption runs up to 1 g U/L. Uranium is readily stripped from Levextrel resin with water. The kinetics of this process are controlled by particle diffusion and can be described by the simplified equation proposed by Vermeulen. Values of diffusivity of uranium in Levextrel resin were lower than in water but very significantly higher than in conventional ion exchange resins. © 1990.