2009/04/01 by A. Benhammou, Boumediene Tanouti, L. Nibou +2 · 1 citation
Materials Science · Energy · Health Professions · #Clay minerals and soil interactions #Iron oxide chemistry and applications #Therapeutic Uses of Natural Elements
paper · doi:10.1346/ccmn.2009.0570212
openalex publication_date 2009/04/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
Abstract ‘Ghassoul’ clay is a Mg-rich clay from Morocco which is of great industrial use and interest, but its characterization is still incomplete. The purpose of this study was to provide further details regarding the structure and characteristics of this important commercial clay mineral. Mineralogical and physicochemical characterizations of the raw form of ‘Ghassoul’ clay from Jbel Ghassoul in Morocco, and of its <2 µm size fraction, purified and Na + -saturated, were carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), infrared spectroscopy (IR), and differential and thermogravimetric analysis (DTA/TG). The XRD data revealed that the raw Ghassoul clay consists mainly of a Mg-rich trioctahedral smectite, stevensite, together with quartz and dolomite. The IR spectra consisted of vibrations typical of trioctahedral smectites. The DTA/TG curves were also similar to those of trioctahedral smectites. Chemical analysis confirms that this Mg-rich trioctahedral smectite is a stevensite characterized by a limited isomorphic substitution of Si 4+ by Al 3+ . The thermal transformations examined by in situ XRD as a function of the firing temperature from 100 to 1200°C indicated that stevensite was transformed to enstatite (MgSiO 3 ) at temperatures >800°C and that quartz was transformed to cristobalite when the temperature exceeded 1100°C. These transformations were irreversible. The specific surface area and cation exchange capacity (CEC) of the ‘Ghassoul’ clay are 133 m 2 /g and 75 meq/100 g, respectively. The main exchangeable cation is Mg 2+ (53 meq/100 g).