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Relative Solubility of Corundum, Gibbsite, Boehmite, and Diaspore at Standard State Conditions

Published online by Cambridge University Press:  02 April 2024

F. J. Peryea  and
J. A. Kittrick
F. J. Peryea*
Affiliation:
Department of Agronomy and Soils, Washington State University, Pullman, Washington 99164
J. A. Kittrick
Affiliation:
Department of Agronomy and Soils, Washington State University, Pullman, Washington 99164
*
2Present address: Washington State University, Tree Fruit Research Center, 1100 North Western Avenue, Wenatchee, Washington 98801.
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Abstract

The solubilities of HCl-treated samples of corundum, gibbsite, boehmite, and diaspore in aqueous solutions at 298 K and one atmosphere pressure were determined from undersaturated and supersaturated initial conditions. Solution characteristics at apparent equilibrium were measured and used to calculate equilibrium constants (Kr) for mineral dissolution reactions:

$$\begin{array}{l} A{l_2}{O_3}\left( {corundum} \right) + 3{H^ + } = A{l^3} + 1.5\,{H_2}O,\\ Al{\left( {OH} \right)_3}\left( {gibbsite} \right) + 3{H^ + } = A{l^3} + 3\,{H_2}O,\\ and\\ AlOOH\left( {boehmite\,or\,diaspore} \right) + 3{H^ + } = A{l^3} + 2{H_2}O, \end{array}$$
Assuming solid phase and water activities of unity, log Kr = 3pH - pAl3+ for all three equations. The calculated log Kr values were: 9.01 ± 0.05 (corundum), 7.76 ± 0.14 (gibbsite), 7.49 ± 0.09 (boehmite), and 6.75 ± 0.24 (diaspore), indicating that the relative thermodynamic stabilities under the experimental conditions were: corundum < gibbsite < boehmite < diaspore. The gibbsite value agreed well with that determined independently by another research group using acid-treated subsamples of the same source mineral (7.70 ± 0.02). The calculated Gibbs free energies of formation (kJ/mole) were: -1587.4 ± 2.1 (corundum), -1156.7 ± 1.6 (gibbsite), -921.0 ± 1.5 (boehmite), and -925.1 ± 2.0 (diaspore). The Δ Gfo values of the acid-treated minerals were 1.8 to 12.4 kJ/mole more negative than values recently compiled for untreated mineral samples. This result is attributed to the removal of reactive surface coatings that isolated the bulk mineral phases from the solution phase.

Keywords

Acid solubilityAluminumBoehmiteCorundumDiasporeGibbsite
Type
Research Article
Information
Clays and Clay Minerals , Volume 36 , Issue 5 , October 1988 , pp. 391 - 396
Copyright
Copyright © 1988, The Clay Minerals Society

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Footnotes

1

Scientific Paper 7888, Project 0747, College of Agriculture and Home Economics Research Center, Washington State University, Pullman, Washington 99164.

References

Bloom, P. R. and Weaver, R. M., 1982 Effect of removal of reactive surface material on the solubility of synthetic gibbsites Clays & Clay Minerals 30 281 – 286.CrossRefGoogle Scholar
Chesworth, W., 1978 Discussion: A working model of some equilibria in the system alumina-silica-water Amer. J. Sci. 278 1018 – 1023.CrossRefGoogle Scholar
Dixon, W. J. and Massey, F. J., 1969 Introduction to Statistical Analysis New York McGraw-Hill 114 – 119.Google Scholar
Hemingway, B. S. and Saxena, S. K., 1982 Gibbs free energies of formation forbayerite, nordstrandite, Al(OH)2+, aluminum mobility, and the formation of bauxites and laterites Advances in Physical Geochemistry, Vol. 2 New York SpringerVerlag 285 – 315.CrossRefGoogle Scholar
Hemingway, B. S., Robie, R. M. and Kittrick, J. A., 1978 Revised values for the Gibbs free energy of formation of [Al(OH)− 4 aq], diaspore, boehmite, and bayerite at 298.15 K and 1 bar, the thermodynamic properties of kaolinite to 800 K and 1 bar, and the heats of solution of several gibbsite samples Geochim. Cosmochim. Acta 42 1533 – 1543.CrossRefGoogle Scholar
Hemingway, B. S., Sposito, G. and Sposito, G., 1988 Inorganic aluminum-bearing solid phases The Environmental Chemistry of Aluminum Florida CRC Press, Boca Raton.Google Scholar
Hsu, P. H., Dixon, J. B. and Weed, S. B., 1977 Aluminum hydroxides and oxyhydroxides Minerals in Soil Environments Wisconsin Soil Sci. Soc. Amer. Madison 99 – 143.Google Scholar
Keller, W. D., 1978 Diaspore recrystallized at low temperature Amer. Mineral. 63 326 – 329.Google Scholar
Kittrick, J. A., 1966 The free energy of formation of gibbsite and Al(OH)− 4 by solubility measurements Soil Sci. Soc. Amer. Proc. 30 595 – 598.CrossRefGoogle Scholar
Kittrick, J. A., 1980 Gibbsite and kaolinite solubilities by immiscible displacement of equilibrium solutions Soil Sci. Soc. Amer. J. 44 139 – 142.CrossRefGoogle Scholar
Lindsay, W. L., 1979 Chemical Equilibria in Soils New York Wiley 118 – 127.Google Scholar
May, H. M., Helmke, P. A. and Jackson, M. L., 1979 Gibbsite solubility and thermodynamic properties of hydroxy-aluminum ions in aqueous solution at 25°C Geochim. Cosmochim. Acta 43 861 – 868.CrossRefGoogle Scholar
Sanjuan, B. and Michard, G., 1987 Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C Geochim. Cosmochim. Acta 51 1823 – 1831.CrossRefGoogle Scholar
Sposito, G., 1981 The Thermodynamics of Soil Solutions New York Oxford Univ. Press 83 – 88.Google Scholar
Tardy, Y. and Nahon, D., 1985 Geochemistry of latérites. Stability of Al-goethite, Al-hematite and Fe3+-kaolinite in bauxites and ferricretes. An approach to the mechanism of concretion formation Amer. J. Sci. 285 865 – 903.CrossRefGoogle Scholar
Tettenhorst, R. and Hofmann, D. A., 1980 Crystal chemistry of boehmite Clays & Clay Minerals 28 373 – 380.CrossRefGoogle Scholar
Troland, F. and Tardy, Y., 1987 The stabilities of gibbsite, boehmite, amorphous goethites, and aluminous hematites in bauxites, ferricretes and latérites as a function of water activity, temperature and particle size Geochim. Cosmochim. Acta 51 945 – 957.CrossRefGoogle Scholar
Violante, A. and Huang, P. M., 1984 Nature and properties of pseudoboehmites formed in the presence of organic and inorganic ligands Soil Sci. Soc. Amer. J. 48 1193 – 1201.CrossRefGoogle Scholar
Wefers, K. and Bell, G. M., 1972 Oxides and hydroxides of aluminum Alcoa Research Labs. Tech. Paper 19 20 – 21.Google Scholar