Polar Division of MMC “Norilsk Nikel”, Norilsk, Russia:

E. V. Shulga, Chief Specialist of Center of Engineering Maintenance of Production, e-mail: shulgaev@nk.nornik.ru
A. I. Ryabushkin, Deputy Head of Technical Department of Nickel Plant
A. I. Devochkin, Chief Engineer of Copper Plant
A. I. Yurev, Candidate of Engineering Sciences, Director of Center of Engineering Maintenance of Production

The influence of the surface-active substances used as additives in Cu electrorefining on anode polarization was studied. Anode polarization curves for various concentrations of colloidal additives were presented in Tafel (semi-logarithmic) form. It was established that anode polarization decreases with the increase of thiourea concentration in electrolyte due to the complexes promoting Cu anode dissolution in the anode vicinity. On the contrary, higher concentration of hide glue enhances anode polarization in electrolyte caused by adsorption layer on the electrode surface that inhibits the reaction of Cu anode dissolution. Higher concentration of Aviton surface-active substances demonstrated the similar effect on anode process kinetics. Production tests didn’t show the positive influence of the surface-active substances on anodic current efficiency. The researches proved that all the surface-active substances used in Cu electrorefining react in anode process. Moreover, the rate and the direction of their effect vary. Thiourea leads to anode depolarization while hide glue and Aviton inhibit it.

1. Minotas J. C., Djellab H., Ghali E. Anodic behavior of copper electrodes containing arsenic or antimony as impurities. Journal of Applied Electrochemistry. 1989. Vol. 19, No. 5. pp. 777–783.
2. Laitinen H. A., Onstott E. I. Polarography of Copper Complexes. III. Pyrophosphate Complexes. Journal of the American Chemical Society. 1950. Vol. 72, No. 10. pp. 4724–4728.
3. Levin A. I., Kodomskoy L. N., Rudoy V. M. Izvestiya vuzov. Tsvetnaya metallurgiya = Russian Journal of Non-Ferrous Metals. 1966. No. 7. pp. 33–36.
4. Levin A. I. Teoreticheskie osnovy elektrokhimii (Theoretical basis of electrochemistry). Moscow : Metallurgiya, 1972. pp. 427–429.
5. Martens L. K. Tekhnicheskaya entsiklopediya (Technical encyclopaedia). Moscow : Sovetskaya entsiklopediya, 1931. Vol. 15. 489 p.
6. Gaydarenko O. V., Chernyshov V. I., Chernyshov Yu. I. Sposob izmereniya potentsiala rabochego elektroda elektrokhimicheskoy yacheyki pod tokom (Method of potential measurement of operating electrode of current-carrying electrochemical cell). Patent RF, No. 2106620, IPC G 01 N 27/26. Applied : April 26, 1996. Published : March 10, 1998.