SciELO - Scientific Electronic Library Online

vol.108 número5The development and implementation of industrial hydrometallurgical gallium and germanium recoveryGeostatistical modelling of rock type domains with spatially varying proportions: Application to a porphyry copper deposit índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados



Links relacionados

  • Em processo de indexaçãoCitado por Google
  • Em processo de indexaçãoSimilares em Google


Journal of the Southern African Institute of Mining and Metallurgy

versão On-line ISSN 2411-9717
versão impressa ISSN 0038-223X

J. S. Afr. Inst. Min. Metall. vol.108 no.5 Johannesburg Mai. 2008




Local process investigations on composite electrodes: On the way to understanding design criteria for spray coated anodes in Zn electrowinning



S. SchmachtelI, II; S.E. PustIII; M. ToiminenI; G. WittstockIII; K. KontturiI; O. ForsénII; M.H. BarkerIV

ILaboratory of Physical Chemistry andElectrochemistry, Helsinki University of Technology, Finland
IILaboratory of Materials Chemistry and Corrosion, Helsinki University of Technology, Finland
IIICentre of Interface Science, Department of Pure and Applied Chemistry and Institute of Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Germany
IVOutotec Research Centre, Pori, Finland




Several possible physico-chemical properties of composite electrodes for oxygen evolution are presented to describe experimental data for which a mathematical model had been developed. On this basis, local electrical and electrochemical properties of a composite electrode were investigated with conductive atomic force microscopy (CAFM) and scanning electrochemical microscopy (SECM). It could be shown by CAFM measurement that the boundary between matrix and catalyst particles seemed to have special advantageous electrical properties.
The SECM measurements showed the presence of mass transport phenomena with increased surface concentrations, whilst the thickness of the Nernst diffusion layer was very small. An intermediate was detected and assigned to be hydrogen peroxide. From all species involved in the oxygen evolution reaction (H2O2, H+ and O2), it was concluded that local active spots exist on the electrode on which hydrogen peroxide reacts to oxygen and protons. A two-step two-material process was suggested to explain the whole oxygen evolution mechanism.



“Full text available only in PDF format”




1. AROMAA, J. and J.W. EVANS. Electrowinning of metals. Encyclopedia of Electrochemistry, 2007. vol. 5, p. 159-265.         [ Links ]

2. BEER, H.B. U.S. Pat. Appl. 549,194 (1966); U.S. Pat. 3,632,498 (1972); U.S. Pat. 3,711,385 (1973). 1966.         [ Links ]

3. BEER, H.B. Eur. Pat. Appl. EP0046727; Eur. Pat. Appl. EP0087186, 1982.         [ Links ]

4. PAJUNEN, L.A., JARI and FORSEN, OLOF., The effect of dissolved manganese on anode activity in electrowinning. Hydrometallurgy 2003, Proceedings of the International Symposium honoring Professor Ian M. Ritchie, Vancouver, BC, Canada, Aug. 24-27, 2003. vol. 2: p. 1255-1265.         [ Links ]

5. PLETCHER, D.W. and FRANK, C. Industrial Electrochemistry. 2nd edn. 1990: Chapman and Hall.         [ Links ]

6. HRUSSANOVA, A.M., DOBREV, L., and VASILEV, S. Influence of temperature and current density on oxygen overpotential and corrosion rate of Pb-Co3O4, Pb-Ca-Sn, and Pb-Sb anodes for copper electrowinning: Part I. Hydrometallurgy, 2004. vol. 72: pp. 205-213.         [ Links ]

7. RASHKOV, S.D., TS., NONCHEVA, Z., STEFANOV, Y., RASHKOVA, B., and PETROVA, M. Lead-cobalt anodes for electrowinning of zinc from sulfate electrolytes. Hydrometallurgy, 1999. vol. 52, pp. 223-230.         [ Links ]

8. DATTILO, M.L., L. J. Merrlin composite anode technology for metal electrowinning. 2001.         [ Links ]

9. DATTILO, M.L., L. J. Merrlin composite anodes for copper electrowinning. 1999.         [ Links ]

10. ELECTRODES INTERNATIONAL, I., An insoluble titanium- lead anode for sulfate electrolytes, Electrodes International, Inc.         [ Links ]

11. GAERTNER, F., et al. The cold sprays process and its potential for industrial applications. Journal of Thermal Spray Technology, 2006. vol. 15, no. 2, pp. 223-232.         [ Links ]

12. CATTARIN, S. and MUSIANI, M. Electrosynthesis of nanocomposite materials for electrocatalysis. Electrochimica Acta, 2007. vol. 52, no. 8, pp. 2796-2805.         [ Links ]

13. Electrodes of conductive metallic oxides, Part A and B, S. Trasatti (ed.). 1980/81, Elsevier scientific publishing company.         [ Links ]

14. SCHMACHTEL SÖNKE, T.M., KONTTURI KYÖSTI, FORSÉN OLOF, BARKER, AND MICHAEL, H. Composite electrodes and MnOx for oxygen evolution in metal electrowinning. European metallurgical conference 2007. 2007. Düsseldorf.         [ Links ]

15. SLOANE, N.J.A. Kepler's conjecture confirmed. Nature (London), 1998. 395(6701): pp. 435-436.         [ Links ]

16. JANSSEN, L.J.J. and BARENDRECHT, E. Mass transfer at a rotating ring-cone electrode and its use to determine supersaturation of gas evolved. Electrochimica Acta, 1984. vol. 29, no. 9: pp. 1207-12.         [ Links ]

17. STULIK, K.A., HOLUB, C., MARECEK, K., VLADIMIR and KUTNER, WLODZIMIERZ., Microelectrodes. Definitions, characterization, and applications: (technical report). Pure and Applied Chemistry, 2000. vol. 72, pp. 1483-1492.         [ Links ]

18. O'HARE, D., MACPHERSON, J.V., and WILLOWS, A. On the microelectrode behaviour of graphite-epoxy composite electrodes. Electrochemistry Communications, 2002. vol. 4, no. 3, pp. 245-250.         [ Links ]

19. SZUNERITS, S., PUST, S.E., and WITTSTOCK, G. Multidimensional electrochemical imaging in materials science. Analytical and Bioanalytical Chemistry, 2007. vol. 389, no. 4, pp. 1103-1120.         [ Links ]

20. WILHELM, T. and WITTSTOCK, G. Generation of periodic enzyme patterns by soft lithography and activity imaging by scanning electrochemical microscopy. Langmuir, 2002. vol. 18, no. 24, pp. 9485-9493.         [ Links ]

21. WITTSTOCK, G., ASMUS, T., and WILHELM, T. Investigation of ion-bombarded conducting polymer films by scanning electrochemical microscopy (SECM). Fresenius J Anal Chem FIELD, 2000. vol. 367, no. 4, pp. 346-51. FIELD Reference Number: FIELD Journal Code:9114077 FIELD Call Number:.         [ Links ]

22. ATKINS, P.W. Physical Chemistry, 6th Edition. 1998. 1014 pp.         [ Links ]

23. KASKIALA, T. and SALMINEN, J. Oxygen solubility in industrial process development. Industrial and Engineering Chemistry Research, 2003. vol. 42, no. 8, pp. 1827-1831.         [ Links ]

24. SHEN, Y., TRAEUBLE, M., and WITTSTOCK, G. Detection of Hydrogen Peroxide Produced during Electrochemical Oxygen Reduction Using Scanning Electrochemical Microscopy. Analytical Chemistry (Washington, DC, United States), 2008. vol. 80, no. 3, pp. 750-759.         [ Links ]

25. LARRY, R. and FAULKNER, A.J.B. Electrochemical Methods Fundamentals and Application Second Edition. 2001: John Wiley \& Sons, INC.         [ Links ]

26. LOBO, V.M.M. Handbook of electrolyte solutions Part A. physical science data, V.M.M. Lobo (ed.). vol. 41. 1989, Amsterdam: Elsevier.         [ Links ]

27. JUERMANN, G., SCHIFFRIN, D.J., and TAMMEVESKI, K. The pH-dependence of oxygen reduction on quinone-modified glassy carbon electrodes. Electrochimica Acta, 2007. vol. 53, no. 2, pp. 390-399.         [ Links ]

28. NEFEDOV, V.G., ARTYUSHENKO, O.A., and KASHEVAROVA, E.V. Mass transfer to horizontal gas-generating electrodes. Russian Journal of Electrochemistry, 2006. vol. 42, no. 6, pp. 638-642.         [ Links ]

Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons