RECOVERY OF COBALT(II) BY THE HYBRID LIQUID MEMBRANE − ELECTRODIALYSIS − ELECTROLYSIS PROCESS

• Simultaneous removal and electrodeposition of Co(II) are achieved during electrodialysis.
• Transport of Co(II) from H2SO4 solutions through bulk liquid membranes was studied.
• Di(2-ethylhexyl)phosphoric acid with admixtures of tri-n-octylamine was used as a carrier.
• Complete removal of Co(II) from the feed solution is achieved.
• Adherent Co electrodeposits with fine-grained structure are obtained.

A novel method for cobalt(II) recovery from acidic solutions is presented. The extraction of cobalt(II) ions using the bulk liquid membrane during a galvanostatic electrodialysis-electrolysis process was studied. Solutions of di (2-ethylhexyl) phosphoric acid with admixtures of tri-n-octylamine in 1,2-dichloroethane were used as liquid membranes. Effects of current density (2.1–5.7 mА·сm−2), cobalt(II) concentration (1·10−3–0.05 mol·L−1) and acid concentration (1·10−3–0.1 M) in the feed solution, carrier concentration in the liquid membrane (5–50 vol %), of the type and concentration of acid (1·10−3–2.5 ·10−2 M) in the cathodic solution were studied, and optimal conditions were determined. Under the optimal conditions it was possible to extract > 99% of cobalt(II) from the acidic feed solution containing 0.01 mol·L−1 CoSO4. A possibility of effective (> 75%) transfer of cobalt(II) into dilute solutions of perchloric, sulphuric, hydrochloric and nitric acids was demonstrated. Adherent, compact cobalt electrodeposits with a fine-grained structure were obtained in the studied systems.

Figure optionsDownload as PowerPoint slide