The extraction of nickel and cobalt by mixtures of 5,8-diethyl-7-hydroxy-6-dodecanone oxime (H2Ox, active extractant in LIX63, a product of Henkel Corp.) and dinonylnaphthalene sulfonic acid (HDNNS or HD) has been studied by using the methods of slope analysis and continuous variation. On the basis of distribution and spectrophotometric data, the observed synergic extraction of nickel and cobalt by H2Ox-HDNNS mixtures is attributed to the formation of a mixed ligand complex with the stoichiometry: Me/H2Ox/HDNNS = 1/3/2. In the absence of H2Ox, log D versus log [HDNNS] plots give straight lines with slopes of unity for both nickel and cobalt extraction, thus indicating that the active extractant is the HDNNS micelle. In the presence of H2Ox the log D versus log [HDNNS] plots go through a maximum and a minimum. It is proposed that the active extractant under these conditions is a mixed HDNNS-H2Ox micelle of the form (HD)p·3H2Ox, and that the shape of the metal distribution curve, as a function of HDNNS concentration, follows the organic-phase concentration of this mixed micelle.
All Science Journal Classification (ASJC) codes
- Industrial and Manufacturing Engineering
- Metals and Alloys
- Materials Chemistry