Paper Title
Solvent Extraction Of Cobalt (Ii) From Sulfate Medium Using Capric Acid-Chloroform–Mibk System

Abstract
The synergistic solvent extraction of cobalt (II) from 0.33 mol dm-3 Na2SO4 aqueous solutions with capric acid (HL) using chloroform/ isobutyl ketone (MIBK) as mixed solvent was carried out at 25°C. The experimental data for the capric acid dissolved in chloroform reveal the self adduct formation, CoL2(HL)2, in the organic phase . In the presence of MIBK, a remarkable enhancement on the extraction of cobalt (II) with 0.02 mol dm-3 capric acid was observed upon the addition of 0.04 to 0.2 mol dm-3 MIBK in chloroform. From an synergistic extraction equilibrium study, the synergistic enhancement was ascribed to the adduct formation CoL2(HL)2(MIBK). The synergistic extraction stoichiometry of cobalt (II) with capric acid and MIBK is studied with the methods of slope analysis. The value of the equilibrium constants were determined. The partition and dimerization constants have been determined in chloroform-sodium sulfate system. Keywords— Solvent extraction, mixed solvent, MIBK, adduct formation constant, cobalt (II), Capric acid.