Formation of mixed complexes during extraction of nitric acid by zirconium di-2-ethylhexylphosphate

Formation of ZrA4-x(NO3)x(HA)2 complexes at x=0,1,2,3 in organic phase is determined by means of analysis of 31P-{1H} NMR spectra of ZrA4(HA)2-HNO3-H2O-C10H22 extraction system (HA- is di-2-ethylhexylphosphoric acid). Partial concentrations of these complexes are determined, and it is shown, that nitric acid extraction by complexes of zirconium di-2-ethylhexylphosphate occurs when NO3- anions substituding for A- anions up to (NO3-)/(Zr4+)≤3 concentrations relation in organic phase. At higher relation of these concentrations the nitric acid occurs in organic phase in free state. It is shown, that mixed complexes are deprived of the ability to extract metal ions, in particular-strontium. Acidic and donor-acceptor properties of zirconium complex ligands are discussed