Studies on extraction of uranium (VI) with N, N dialkyl substituting amides and triotyl phosphine oxide

An investigation of the use of N, N-di-n-pentyl acetamide (DPAA), N, N-di-n-octyl acetamide (DOAA), N, N-di-n-pentyl propyl amide (DPPA) and N, N-2-methylheptyl acetamide (N-503) as extracants for the extraction of uranium (VI) from nitric acid solution has been made. The equilibrium constants were determined to be logβ10 = 0.218, 0.639, 0.702 and 0.955 respectively. It was found that N-503 is the best extractant of this type since its synthetizing is cheap, it exhibits a similar behavior as tri-n-butyl phosphate (TBP). Additional studies have been performed on trioctyl phosphine oxide (TOPO) extractant and the equilibrium constant logβ20 is equal to 2.87. For the purpose to increase the extracting power, a binary synergic extracting system composed of two neutral complex ligands, namely BB species for uranium (VI), was studied. The binary synergic equilibrium constants were measured to be logβ12 = 1.30 (DPAA + TOPO system) and logβ13 = 1.36 (DPAA + N503 system)