Abstract
Aqueous solutions with about 10 ppt195Au and [HCl] of 10−2.3 and 10−1.3 m were exposed to solid minerals for several months. The gold uptake with time was observed by time-stepped sampling and radiochemical Au analysis. Sorbants were polished thick sections of quartz, pyrite, pyrrhotite and elemental gold, as well as crushed grains and sawed mineral cubes of quartz and pyrite (all randomly oriented). The kinetics of gold sorption strongly varied with the surface area of the sorbents, the type of mineral and the pH of the solution. Mineral-specific differences in reaction rates were observed only at experimental pH values around 2.3, where sorption on pyrrhotite and elemental gold was much more rapid than by quartz and pyrite. At pH around 1.3 gold sorption was rapid on all minerals. This finding is thought to reflect the gold speciation, i.e. neutral hydroxo-gold complexes above pH 1.5, for which only chemisorption is possible, versus dominantly AuCl −4 below pH 1.5, where unspecific electrostatic interaction enhances reaction rates with all protonated mineral surfaces.
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Bancroft, G.M., Hyland, M.M. (1990) Spectroscopic studies of adsorption/reduction reactions of aqueous metal complexes on sulphide surfaces. In: Hochella, M.F., White, A.F. (eds.) Mineral-water interface geochemistry. Mineral. Soc. America Rev. Mineral. 23: 511–558
Bakken, B.M., Hochella, M.F., Marchall, A.F., Turner, A.M. (1989) High resolution microscopy of gold in unoxidized ore from the Carlin mine, Nevada. Econ. Geol. 84: 171–179
Baranova, N.N., Ryzhenko, B.N. (1981) Computer simulation of the Au-Cl-S-Na-H2O system in relation to the transport and deposition of gold in hydrothermal processes. Geochem. Int. 18: 46–60
Falkner, K.K., Edmond, J.M. (1990) Gold in seawater. Earth Planet. Sci. Lett. 98: 208–221
Hayashi, K.-I., Ohmoto, H. (1991) Solubility of gold in NaCl- and H2S-bearing aqueous solutions at 250–350°C. Geochim. Cosmochim. Acta 55: 2111–2126
Heinhorst, J.-P. (1992) Experimente zur Kinetik der Gold-Fixierung auf Mineraloberflächen. M.Sc. thesis, Freie Universität Berlin, 74 pp
Jean, G.E., Bancroft, G.M. (1985) An XPS and SEM study of gold deposition at low temperatures on sulphide mineral surfaces: concentration of gold by adsorption/reduction. Geochim. Cosmochim. Acta 49: 979–987
Knipe, S.W., Foster, R.P., Stanley, C.J. (1991) Hydrothermal precipitation of precious metals on sulphide substrates. In: Ladeira, E.A. (ed.) Brazil gold '91. Balkema, Rotterdam, pp. 431–435
Machesky, M.L., Wilson, O.A., Rose, A.W. (1991) Adsorption of gold(III)-chloride and gold(I)-thiosulfate anions by goethite. Geochim. Cosmochim. Acta 55: 769–776
Mann, A.W. (1984) Mobility of gold and silver in lateritic weathering profiles: some observations from Western Australia. Econ. Geol. 79: 38–49
McHugh, J.B. (1988) Concentration of gold in natural waters. J. Geochem. Expl. 30: 85–94
Mironov, A.G., Zhmodik, S.M., Maksimova, E.A. (1981) An experimental investigation of the sorption properties of gold by pyrites with different thermoelectric properties. Geochem. Int. 18: 153–160
Ney, P. (1973) Zeta Potentiale und Flotierbarkeit von Mineralen. Springer, Berlin Heidelberg New York, 214 p.
Parks, G.A. (1990) Surface energy and adsorption at mineral water interfaces: an introduction. In: Hochella, M.F., White, A.F. (eds.) Mineral-water interface geochemistry. Mineral. Soc. America Rev. Mineral. 23: 133–175
Renders, P.J., Seward, T.M. (1989) The adsorption of thio gold(I) complexes by amorphous As2S3 and Sb2S3 at 25 and 90°C. Geochim. Cosmochim. Acta 53: 255–267
Santosh, M., Omana, P.K. (1991) Very high purity gold from lateritic weathering profiles of Nilambur, Southern India. Geology 19: 746–749
Schneider, H.J. (1986) Das geochemische Verhalten von Gold bei der Lagerstättenbildung. In: Walther, H.W. (ed.) Edelmetalle. GDMB Schriften 44: 27–36
Schoonen, M.A.A., Fisher, N.S., Wente, M. (1992) Gold sorption onto pyrite and goethite: a radiotracer study. Geochim. Cosmochim. Acta 56: 1801–1814
Shuey, R.T. (1975) Semiconducting ore minerals. Elsevier, Amsterdam, 415 p.
Stone, A.T., Morgan, J.J. (1990) Kinetics of chemical transformation in the environment. In: Stumm, W. (ed.) Aquatic chemical kinetics. Wiley, New York, pp. 1–43
Stumm, W., Morgan, J.J. (1981) Aquatic chemistry: an introduction emphasizing chemical equilibria in natural waters. 2nd ed., Wiley, New York, 780 p.
Vlassopoulos, D., Wood, S.A. (1990) Gold speciation in natural waters I: solubility and hydrolysis reactions of gold in aqueous solutions. Geochim. Cosmochim. Acta 54: 3–12
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Heinhorst, J.P., Lehmann, B. A radiotracer study on the kinetics of gold sorption by mineral surfaces. Mineral. Deposita 29, 399–403 (1994). https://doi.org/10.1007/BF01886957
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DOI: https://doi.org/10.1007/BF01886957