Proferential Hydroxyaluminum Interlayering in Montmorillonite and Vermiculite1
- R. I. Barnhisel and
- C. I. Rich2
The rate of Al diffusion in both montmorillonite and vermiculite was a function of the relative humidity, and the initial saturating cation. In both clay systems, it is proposed that Al-interlayers were produced in alternate layers giving a regularly interstratified sequence. The clay exhibited 001 reflections integral with a 25A to 27A spacing. These high angstrom spacings were obtained only after the clays had been heated to temperatures of 110 and 300C for montmorillonite and vermiculite, respectively. The sequence is believed to consist of alternating layers, one predominately Al-saturated and the other Na-saturated. The Al layers contained enough hydroxy-Al to provide sufficient stability to these layers to prevent their collapse when the samples were heated at moderate temperatures. The Na layers were either partially or completely dehydrated when heated and these layers collapsed to either 12A or 10A.
The difference in the temperature required to produce the regular interstratification in vermiculite is presumably related to the rapid rehydration of vermiculite samples after the 110C heat treatments.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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