J. Phys. IV France 123 (2005) 361–364 C  EDP Sciences, Les Ulis DOI: 10.1051/ jp4:2005123066 Diatomite based ceramics macro- and microscopic characterization H. Aderdour 1,2,* , A. Bentayeb 1 , A. Nadiri 1 , A. Ouammou 3 , J.-C. Sangleboeuf 4 , A. Lucas-Girot 5 and C. Carel 6 1 UFR « Sciences des Matériaux Inorganiques », Faculté des Sciences, Université Moulay Ismaîl, Meknès, Maroc, (*) Deceased, May 2002 2 École Nationale Supérieure d´Arts et Métiers, Université Moulay Ismaîl , Meknès, Maroc 3 Laboratoire de Matériaux et Protection de l´Environnement, Faculté des Sciences Dhar El Mahrez, BP. 1796, Atlas, Fès, Maroc 4 LARMAUR - UPRES-JE 2310, Équipe de Mécanique des Matériaux Fragiles, Campus Beaulieu, Bâtiment 10B, CS 74205, 35042 Rennes, France 5 Laboratoire CSIM - UMR CNRS 6511, Équipe de Cristallochimie et Biomatériaux, Campus Beaulieu, Bâtiment 10B, CS 74205, 35042 Rennes, France 6 27A Cours Raphaël Binet, 35000 Rennes, France Abstract. A Moroccan diatomite is characterized chemically and physically. Mechanical properties of ceramics prepared by sintering at different temperatures ranging from 1050 to 1350 ◦ C are studied. Compressive strength andYoung modulus are determined by compression tests. Densification and evolution of the microstructure are followed by SEM and other tests. Key words: diatomite; sintering; microstructure; compression test; Young modulus 1. INTRODUCTION Diatomite is a sedimentary rock that results from the fossilized skeletal remains of diatoms, single cell plants that live in both salt and fresh waters. These remains or frustules consist of vitreous silica as clusters of opal SiO 2 ,nH 2 O, and crystallized silica [1,2]. The intrinsic porosity and purity of diatomite are attractive characteristics that allow for the use of this raw material as a filter aid, absorbent, thermal insulator, refractory and a source of reactive silica; as a filler and extender in paint, paper, rubber and plastics, and as a catalyst carrier and chromatography support [3]. The purpose of this work is to characterize ceramics obtained by sintering at high temperature of diatomite collected from the region of Ras Traf in North Morocco [4]. 2. AS-RECEIVED MATERIALAND PREPARATION OF CERAMICS The chemical analysis expressed in weight percent of oxides is as follows: SiO 2 =69.00, Al 2 O 3 =4.37, Fe 2 O 3 =2.58, MgO=1.08, CaO=5.30, Na 2 O=1.80, K 2 O=0.67, SO 3 =0.10 [5-7]. The loss on ignition at 1000 ◦ C is equal to 14 wt%, and is thought to be due mainly to the disappearence of organic matter and opaline water (about 4 wt%). The mineralogical composition performed by XRD analysis reveals the presence in this natural material of amorphous silica, tridymite, quartz and some calcite. The apparent density is around 0.3, the real density is 2.21. The average grain size d 50 is 13.4 m, the BET surface area is 14.3 m 2 g -1 . A previous dilatometric investigation of the sintering behavior during heating at a rate of 10 ◦ C.mn -1 can be found in ref. [5]. The dilatograms have been reinterpreted and show that up to 680 ◦ C no dimensional change is observed, but between 680 and 1080 ◦ C a continuous shrinkage is observed. Between 1080 and Article published by EDP Sciences and available at http://www.edpsciences.org/jp4 or http://dx.doi.org/10.1051/jp4:2005123066