EXTRACTION OF NEPTUNIUM FROM ACIDIC SOLUTIONS BY ORGANIC NITROGEN AND PHOSPHORUS COMPOUNDS

Neptunium distribution coefficients from acid nitrate, chloride, and sulfate solutions by several organic nitiogen and phosphorus compounds were measured as functions of several extraction variables, including neptunium valence, acid and salt concentration, and reagent concentration. Extractability by all the reagents varied in the order Np(IV)> Np(VI)>> Np(V). Except for primary amines, all reagents extracted Np(IV) much more strongly from nitrate than sulfate solutions. Among organonitrogen compounds the order of extractability of Np(IV) was: quaternary> tertiary> primary and secondary from nitrate solutions but primary>> secondary> tertiary from sulfate solutions. Neptunium(IV) nitrate extractions with the different extractants passed through maxima at widely different acid concentrations. In most cases, extraction increased when nitric acid was replaced by nitrate salt. Extraction was usually approximately proportional to the square of the reagent concentration. (auth