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Stability of hectorite in weakly acidic solutions. II. Studies of the chemical equilibrium and the calculation of free energy

Published online by Cambridge University Press:  09 July 2018

Kevin G. Tiller*
Affiliation:
Division of Soils, C.S.I.R.O., Adelaide, South Australia

Abstract

The chemical equilibrium of a purified sample of hectorite was studied over a range of pH, silicic acid, and magnesium chloride concentrations. The quasi-equilibrium reached by about 6 weeks was reversible with respect to added magnesium ions but only partially so for added silicic acid. The free energy of formation of hectorite at 25° C was calculated at −2680 kcal/unit cell, using the derived equilibrium constant and the stoichiometry of the reaction as previously established.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1968

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References

Barany, R. & Kelly, K.K. (1961) U.S. Bur. Mines Rept. Inves. No. 5825.Google Scholar
Garrels, R.M. (1957) Am. Miner. 42, 780791.Google Scholar
Garrels, R.M. (1960) Mineral Equilibria at Low Temperature and Pressure, Harper and Brothers, New York.Google Scholar
Grim, R.E. (1953) Clay Mineralogy. McGraw-Hill, New York.Google Scholar
Kittrick, J.A. (1966) Am. Miner. 51, 14571466.Google Scholar
Latimer, W.M. (1952) The Oxidation States of the Elements and their Potentials in Aqueous Solutions. Prentice-Hall, Englewood Cliff.Google Scholar
Polzer, W.L & Hem, J.D. (1965) J. geophys. Res. 70, 62336240.CrossRefGoogle Scholar
Tiller, K.G. (1968) Clay Miner. 7, 245.Google Scholar
van, Lier J.A., De Bruyn, P.L. & Overbeek, J.TH.G. (1960) J.phys. Chem., Wash. 64 16751682.Google Scholar
Wise, S.S., Margrave, J.L., Feder, H.M. & Hubbard, W.N. (1963) J. phys. Chem., Wash. 67, 815821.CrossRefGoogle Scholar