Abstract
The surface oxidation of galena in air and in aqueous media has been investigated using electron spectroscopy and linear potential sweep voltammetry to elucidate the incongruent oxidation indicated by previous X-ray photoelectron spectroscopic studies. It has been confirmed that the initial oxidation reaction involves the removal of lead atoms from the sulfide lattice to generate a metal-deficient surface layer. It has been shown that, when the mineral is removed from the oxidizing environment, the composition of this layer relaxes slowly back towards that of the bulk mineral as a result of lead atoms diffusing from the bulk to the surface to fill metal vacancies in the sulfide lattice. The relaxation accounts for the absence of a shifted component in sulfur electron spectra from galena exposed to air or basic solutions in equilibrium with air. Correlation of the potential dependence of self-induced flotation and the extent of surface sulfur excess determined electrochemically indicates that a metal-deficiency equivalent to about half a monolayer of excess sulfur is necessary for significant flotation to be effected.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
K. L. Sutherland and I. W. Wark, ‘Principles of Flotation’, Aust. Inst. Min. Metall., Melbourne, Australia (1955).
W. J. Trahar, in ‘Principles of Mineral Flotation, The Wark Symposium’ (edited by M. H. Jones and J. T. Woodcock), Aust. Inst. Min. Metall., Melbourne, Australia (1984), pp. 117–135.
R. Woods, Chemistry in Australia 58 (1991) 392.
A. N. Buckley and R. Woods, in ‘Proceedings of the International Symposium on Electrochemistry in Mineral and Metal Processing’ (edited by P. E. Richardson, S. Srinivasan and R. Woods), The Electrochemical Society, Pennington, NJ (1984) PV 8410, pp. 286–302.
A. N. Buckley, I. C. Hamilton and R. Woods, in ‘Developments in Mineral Processing’, Vol. 6, ‘Flotation of Sulphide Minerals’ (edited by K. S. E. Forssberg), Elsevier, Amsterdam (1985), pp. 41–60.
P. J. Guy and W. J. Trahar, Int. J. Miner. Process. 12 (1984) 15.
A. N. Buckley and R. Woods, Appl. Surf. Sci. 17 (1984) 401.
A. N. Buckley and G. W. Walker, in ‘Proc. XVI Int. Miner. Process. Congress’ (edited by K. S. E. Forssberg), Elsevier, Amsterdam (1988), pp. 589–599.
A. N. Buckley and K. W. Riley, Surf. Interface Anal. 17 (1991) 655.
A. N. Buckley, I. M. Kravets, A. V. Shchukarev and R. Woods, J. Appl. Electrochem. 24 (1994) 513.
A. N. Buckley and R. Woods, Aust. J. Chem. 37 (1984) 2403.
Idem, Appl. Surf. Sci. 20 (1985) 472.
Idem, ibid. 22/23 (1985) 280.
Idem, Surf. Interface Anal. 17 (1991) 675.
D. J. Vaughan and J. R. Craig, ‘Mineral Chemistry of Metal Sulfides’, Cambridge University, Cambridge, UK (1978).
T. Biegler, D. A. J. Rand and R. Woods, J. Electroanal. Chem. 60 (1975) 151.
R. Woods, J. Phys. Chem. 75 (1971) 354.
L. R. Pederson, J. Electron Spectrosc. 28 (1982) 203.
J. M. Thomas and M. J. Tricker, J. Chem. Sac. Faraday II 71 (1975) 329.
K. Laajalehto, R. St. C. Smart, J. Ralston and E. Suoninen, Appl. Surf. Sci. 64 (1993) 29.
M. Pourbaix, ‘Atlas D'Equilibres Electrochimiques’, Gauthier-Villars, Paris (1963).
J. R. Gardner and R. Woods, J. Electroanal. Chem. 100 (1979) 447.
D. S. Zingg and D. M. Hercules, J. Phys. Chem. 82 (1978) 1992.
H. T. Minden, ibid. 23 (1955) 1948.
G. D. Senior and W. J. Trahar, Int. J. Miner. Process. 33 (1991) 321.
Yu. I. Ravich, B. A. Efimova and I. A. Smirnov, ‘Semiconducting Lead Chalcogenides’, Plenum, New York (1970).
M. Sato, Econ. Geol. 55 (1960) 1202.
E. Peters, in ‘Trends in Electrochemistry’ (edited by J. O'M. Bockris, D. A. J. Rand and B. J. Welch), Plenum, New York (1977), pp. 267–290.
M. Kobayashi and H. Kametani, Hydromet. 22 (1989) 141.
P. E. Richardson, R.-H. Yoon, R. Woods and A. N. Buckley, Int. J. Miner. Process. 41 (1994) 77.
E. Peters, in ‘Proceedings of the International Symposium on Electrochemistry in Mineral and Metal Processing” (edited by P. E. Richardson, S. Srinivasan and R. Woods), The Electrochemical Society, Pennington, NJ (1984), PV 84–10, pp. 343–61.
R. Tolun and J. A. Kitchener, Trans. IMM 73 (1964) C313.
J. Bloem, Philips Res. Rep. 11 (1956) 273.
D. F. A. Koch and R. J. McIntyre, J. Electroanal. Chem. 71 (1976) 285.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Buckley, A.N., Woods, R. Relaxation of the lead-deficient sulfide surface layer on oxidized galena. J Appl Electrochem 26, 899–907 (1996). https://doi.org/10.1007/BF00242041
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00242041