Stability of Montmorillonites: II. Aberdeen Montmorillonite1
- J. A. Kittrick2
Six montmorillonite samples from Aberdeen, Mississippi were equilibrated with various solutions for 3–4 years. Under the conditions of these experiments, Aberdeen montmorillonite was found to be less stable than Belle Fourche montmorillonite and kaolinite. Locating the Aberdeen solubility line under conditions where it is metastable was difficult because of the tendency of the samples to approach the nearest stable solubility line. It was possible to locate the position of the metastable montmorillonite solubility line only because two of the six samples resided there briefly before approaching the more stable kaolinite solubility line. The resulting three points were in close agreement with the calculated slope and intercept of the montmorillonite solubility line on pH-⅓pAI3+ vs. pH4SiO4 axes, as derived from the unit cell formula of Aberdeen montmorillonite. A ΔG of −2450.3±0.1 kcal per mole was obtained for Aberdeen montmorillonite, based upon the assumption that Fe3+ in solution was controlled by hematite.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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