山形産モンモリロナイトの交換性陽イオン組成

抄録

Aside from a clay mineralogical interest, it is also important in industrial usage to understand the nature of the exchangeable cation in montmorillonite. A montmorillonite sample obtained from the bentonite deposit of the Tsukinuno mine in Yamagata prefecture was treated repeatedly with either 70% 2-propanol solution, Na-exchanged or dialyzed. Changes were monitored in the montmorillonite after treatment which includes CEC, LC (i.e. cation leaching by NH₄-Ac), XRD and TG-DTA analysis. Results show that approximately 95% of the exchangeable cations in the Yamagata montmorillonite is Na⁺ ion. This suggests that the montmorillonite sample is an almost pure Namontmorillonite, and consequently, Yamagata bentonite which composed mainly of Yamagata montmorillonite is an almost pure Na-bentonite.