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  • Author or Editor: E. Jünger x
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Abstract  

The nitrate salt solution of the secondary amine Amberlite LA-1 in organic solvents extracts uranium(IV) from aqueous nitric acid solutions. The distribution ratio of uranium(IV) reaches a maximum at an equilibrium nitric acid concentration of 8.5M in the aqueous phase. Addition of n-octanol to the organic phase decreases, and the addition of nitrate to the aqueous phase increases the uranium(IV) distribution ratio. The extraction of uranium(IV) is fast and the equilibrium distribution is reached within less than one minute. At low uranium(IV) concentrations (<6·10−3 M) the distribution ratio is independent of the uranium(IV) concentration. At high uranium(IV) loadings of the organic phase an extrapolation gives a mole ratio of amine: uranium(IV)=2∶1. A double logarithmic plot of the dependence of the uranium(IV) distribution ratio vs. the LA-1 concentration in the organic phase gives a curve with a slope of two when polar diluents for LA-1 are used. This slope of two and the shapes of the absorption spectra of the organic phase from 400 to 700 nm make it very probable that uranium(IV) exists in the organic phase as a hexanitrato complex.

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Abstract  

The distribution of uranium(IV) between aqueous nitric acid solutions and solutions of the nitrate salt of the primary amine Primene JM-T in various diluents is described. The influence of the concentration of the acid, nitrate and perchlorate in the aqueous phase is studied, taking into account the complex composition of uranium(IV) in the aqueous phase and the acid content of the organic phase. The uranium(IV) extraction may be explained by the competition between metal complex and nitric acid for the extracting agent. The absorption spectra of the organic phase and the results of maximum loading experiments indicate that the uranium(IV) species in the organic phase is the bis-alkylammonium-hexanitrato-uranium(IV) complex [(RNH3)2U(NO3)6].

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