SYNERGISM, ANTAGONISM AND SELECTIVITY IN THE LIX63-HDNNS METAL EXTRACTION SYSTEM.

There have been a number of reports in which the addition of the acidic liquid cation exchanger dinonylnaphthalene sulfonic acid (HDNNS or HD) to chelating reagents has been found to produce synergistic extraction and/or improved kinetics Of particular interest is the mixed system consisting of this sulfonic acid and the anti-isomer of 5,8-diethyl-7-hydroxy-6-dodecanone oxime (H//2L, the active extractant in the commercial reagent LIX63. The selective extraction of Cu(II), Ni(II), and Co(II) from Fe(III) has been reported. The synergistic extraction of nickel and cobalt by this sulfonic acid-hydroxyoxime mixture has been attributed to the ability of HDNNS micelles to solubilize both the hydroxyoxime molecules and the metal ions and the ability of the oxime to chelate these metals without deprotonating. In this paper, new data on the behavior of Fe(III) are compared with the results previously reported for Ni(II) and Co(II).