Extraction of Ni and Co via D2EHPA in the Presence of Acetate Ion

The effect of acetate ion introduced to aqueous solutions was investigated for the extraction/separation of Ni and Co from a dilute sulfate media. The separation of Co and Ni was improved by introducing acetate to aqueous media. By the use of the slope analysis method,the stoichiometric coefficient of the extractant was found to be 4 for cobalt and 3.5 or 4 for nickel depending on the acetate concentration. Fourier Transform Infrared Spectroscopy (FT-IR) was utilized to examine the probable“metal-acetate-D2EHPA” complexes. Increasing the level of acetate, up to 0.4 M showed a relatively significant effect on the extraction curve of Ni, but there was no influence in the Co extraction curve. At the acetate level of 0.6 M, the pH difference at 70 extraction percentage reached ~0.55 in compared to ~0.2in the absence of acetate.