N,N,N',N'-tetrahexylsuccinylamide as a new extractant for the extraction of nitric acid, uranium(VI) and thorium(IV) ions

N,N,N',N'-tetrahexylsuccinylamide (THSA) was used for the extraction of U(V I) and Th(IV) ions from nitric acid media into n-dodecane. Extraction distr ibution ratios of U(VI) and Th(IV) as a function of nitric acid concentrati on, extractant concentration and temperature have been studied. It was foun d that THSA as a new extractant is superior in some aspects to TBP for extr action of U(VI) and Th(IV). The extraction of nitric acid was also investig ated. At low acidity, the main adduct of THSA and HNO3 is THSA.HNO3. THSA ( HNO3)(2) and THSA.(HNO3)(2) also formed at high acidity. The composition of the species, equilibrium constants and enthalpies of the extraction reacti ons have also been calculated. The suggested formation of the 1:2:1 ratio o f uranyl(VI) ion and the 1:4:2 ratio of thorium(IV) ion, nitrate ion and TH SA as the extracted species was further confirmed by the IR spectra of U(VI ) and Th(IV) extracts.