Note Synthesis and characterization of cordierite ceramic from Moroccan stevensite and andalusite R. Bejjaoui a , A. Benhammou b, ⁎, L. Nibou b , B. Tanouti a , J.P. Bonnet c , A. Yaacoubi a , A. Ammar a a Faculté des Sciences Semlalia, Avenue My. Abdellah, Université Cadi Ayyad, BP, 2390, Marrakech, Maroc b Ecole Nationale des Sciences Appliquées ENSA, Université Cadi Ayyad, Route Sidi Bouzid, BP 63, Safi, Maroc c Ecole Nationale de Céramique Industrielle ENSCI, Avenue Albert Thomas, 87065 Limoges Cedex, France abstract article info Article history: Received 2 February 2010 Received in revised form 27 May 2010 Accepted 2 June 2010 Available online 10 June 2010 Keywords: Moroccan Ghassoul Stevensite Andalusite Cordierite Characterization Cordierite (2MgO-2Al 2 O 3 -5SiO 2 ) is currently an attractive ceramic material for various applications. This study describes the production of cordierite ceramic by mixing Moroccan abundant raw materials: andalusite (source of Al 2 O 3 and SiO 2 ) and “Ghassoul” clay (source of MgO and SiO 2 ). The clay consists mainly of stevensite. The mixtures (size b 40 μm) were sintered at 1150, 1250 and 1350 °C for 2 h. The phases formed and structural changes by sintering were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), thermal dilatometry and scanning electron microscopy (SEM). Cordierite and andalusite were the major phases in samples sintered at 1150 °C and 1250 °C. Small amounts of enstatite, mullite and cristobalite were also observed. At 1350 °C, only cordierite was observed. The exothermic peak of the DTA curve at about 1350 °C corresponded to the solid-state formation of cordierite. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Cordierite (2MgO,2Al 2 O 3 ,5SiO 2 ) is one of the important phases of the MgO–SiO 2 –Al 2 O 3 system due to many industrial applications. Cordierite ceramics have excellent thermal shock resistance due to their low thermal expansion coefficient, low dielectric constant, high refractori- ness and high mechanical strength (Tulyaganov et al., 2002; Goren et al., 2006). Therefore, cordierite based materials are extensively used in a broad range of applications, including catalysts, microelectronic, integrated circuit boards, membranes and refractories (Scardi et al., 1994; Zhou et al., 2005; Kolli et al., 2007). Cordierite ceramic materials were extensively investigated and several syntheses were proposed (Karagedov et al., 1991; Johnson et al., 2003). The most common method to synthesize cordierite is the high temperature reaction by a solid-state reaction. The conventional methods for synthesis of cordierite ceramics include the solid-state sintering of MgO, Al 2 O 3 and SiO 2 in ratios corresponding to the chemical composition of cordierite (2MgO,2Al 2 O 3 ,5SiO 2 ). In industrial production of cordierite as refractory products, natural raw materials such as talc, kaolin, diatomite, feldspar, and sepiolite are usually used (Kobayashi et al., 2000; Acimovic et al., 2003). This study describes the synthesis of cordierite from Moroccan abundant raw materials: andalusite and the stevensite-rich clay called Ghassoul (Benhammou et al., 2009). Ghassoul clay comes from the only deposit in the world, located at the East side of the Middle Atlas Mountains, in the Moulouya valley, approximately 200 km away from Fes (Chahi et al., 1993). At present, this mineral is essentially marketed as a detergent or traditional shampoo. This clay was first described including the chemical analysis by Damour (1843). The name of Ghassoulite was proposed by Millot (1954) for the mineral extracted from Jbel Ghassoul. The andalusite deposit is located at 7 km west Sidi Bou Othmane village (province of Kalaât Sraghna), 30 km north Marrakech (Arib et al., 2004). 2. Materials and methods 2.1. Raw materials The particle size of stevensite-rich clay and andalusite was b 40 μm. The mineralogical composition of Ghassoul clay indicated 84.2% stevensite, 11% quartz and 4.8% dolomite (Benhammou et al., 2009). The density and specific surface area were 2.24 g/cm 3 and 133 m 2 /g. The chemical compositions of the Ghassoul clay and andalusite are given in Table 1. 2.2. Cordierite synthesis The mixtures of andalusite and stevensite corresponding to the stoichiometric cordierite composition (2MgO,2Al 2 O 3 ,5SiO 2 ) were prepared at room temperature by dry mixing. The composition of the mixture, noted M 1 , was: stevensite (Si 4 Mg 3 O 10 ) 43.7%; andalusite Applied Clay Science 49 (2010) 336–340 ⁎ Corresponding author. Tel.: +212 24 66 91 55; fax: +212 24 66 80 12. E-mail address: Benhammou_ab@yahoo.fr (A. Benhammou). 0169-1317/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.clay.2010.06.004 Contents lists available at ScienceDirect Applied Clay Science journal homepage: www.elsevier.com/locate/clay