FORMATION OF SEPIOLITE-PALYGORSKITE AND RELATED MINERALS FROM SOLUTION
Most of the world's sepiolite-palygorskite precipitates in lacustrine and perimarine environments. Although these minerals can transform from precursor minerals, the most common formation mechanism involves crystallization from solution. In this study, equilibrium activity diagrams are calculated for sepiolite-palygorskite in the seven component system MgO-CaO-Al2O3-SiO2-H2O-CO2- HCl, employing available thermodynamic data for related minerals, aqueous species and water. Stability fields are illustrated graphically on plots of log [aMg2+/(aH+)2] vs . log[aH4SiO4o], using the activities for log[aAl3=/(aH+)3] defined by an arbitrarily chosen value and the approximate saturation limits of pyrophyllite + amorphous silica, kaolinite + amorphous silica, kaolinite + pyrophyllite, pyrophyllite + quartz and gibbsite. The formation of sepiolite-palygorskite from solution is more favored in the presence of amorphous silica than quartz. Lower aqueous aluminum activities favor the non-aluminum phases sepiolite and kerolite relative to the aluminum-containing phases palygorskite and saponite. The stability ranges of worldwide associations of magnesite and dolomite with sepiolite and palygorskite are also illustrated as a function of aluminum activity.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: 2002-12-01
More about this publication?
- The JOURNAL publishes articles of interest to the international community of clay scientists, including but not limited to areas in mineralogy, crystallography, geology, geochemistry, sedimentology, soil science, agronomy, physical chemistry, colloid chemistry, ceramics, petroleum engineering, foundry engineering, and soil mechanics. Clays and Clay Minerals exists to disseminate to its worldwide readership the most recent developments in all of these aspects of clay materials. Manuscripts are welcome from all countries.
Clays and Clay Minerals is the official publication of The Clay Minerals Society.
The Editor-in-Chief is Professor Joseph W. Stucki [email protected]
- Editorial Board
- Information for Authors
- Membership Information
- Annual Meeting of The Clay Minerals Society
- Ingenta Connect is not responsible for the content or availability of external websites