Solvent extraction of praseodymium (3), neodymium (3), samarium (3), europium (3), and gadolinium (3) nitrates by mixtures of diisooctyl methyl phosphonate and trialkylmethylammonium nitrate from water-salt solutions

Extraction of rare earth metals (3) (preseodymium-gadolinium) nitrates by mixtures of diisooctyl-methylphosphonate (S) and trialkylmethylammonium nitrate (A) at different ratios of the components, T=298 . 15 K, pH2, has been considered. It is ascertained that compounds of the composition: [Ln(NO3)3S], [Ln(NO3)3iA] (i=2,3), [Ln(NO3)3·jA(3-j)S](j=1,2) are formed. The values of extraction constants of mixed ligand solvates of rare earth metals (3) nitrates obey statistical factor and decrease in the metal series: Pr>Nd>Sm>Eu>Gd