New Data on Sepiolite and Attapulgite1

Fred A. Mumpton and Rustum Roy
The Pennsylvania State University, University Park, Pennsylvania
1 Contribution no. 56-44, College of Mineral Industries, The Pennsylvania State University, University Park, Pa.

Abstract: Hydrothermal studies have failed to yield synthetic attapulgite or sepiolites in the system MgO-Al2O3-SiO2-H2O. However, the natural minerals can be decomposed to yield montmorillonoids by mild hydrothermal treatment as low as 200°C and probably as low as 100°C. These data indicate that they are metastable and probably could not have formed at these temperatures.

Dry dehydration at 400° and 750°C gave no evidence for the presence of “zeolitic water” in these minerals and failed to establish the existence of “anhydride” phases. The field study of relationships in one sepiolite locality suggests the importance of structural control in the formation of these minerals.

Clays and Clay Minerals; 1956 v. 5; no. 1; p. 136-143; DOI: 10.1346/CCMN.1956.0050111
© 1956, The Clay Minerals Society
Clay Minerals Society (www.clays.org)