Synergistic extraction of Ni(II) by mixtures of LIX 860 and bis(2-ethylhexyl) phosphoric acid

The equilibria of extraction of Ni(II) from 1.0 M nitrate medium by mixtures of LIX 860 and bis-(2-ethylhexyl)phosphoric acid (HDEHP) dissolved in toluene have been studied. Synergistic effects have been obtained and explained in terms of the formation of mixed complexes of stoichiometries NiL2(HL)(HR) and NiL2(HR)(4), HL being 5-dodecylsalicylaidoxime, the active component of LIX 860, and HR representing HDEHP. Values of the equilibrium constants of the extraction reactions are given.