Physicochemical and Geotechnical Characterization and Application of Berriasian Clays of Djebel Oust (North of Tunisia)

December 2006 Volume 2 Issue 6 MaterialsMaterials ScienceScience Trade Science Inc. An Indian Journal Full Paper MSAIJ, 2(6), 2006 [169-175] Physicochemical And Geotechnical Characterization And Application Of Berriasian Clays Of Djebel Oust (North Of Tunisia) Corresponding Author Co-Authors Salah Mahmoudi Ezzeddine Srasra1, Fouad Zargouni2 Département de Géologie, 1Centre des matériaux, Technopole Borj Cedria, BP95, 2050, Faculté des Sciences de Tunisie, Hammam Lif (TUNISIE) 1060 Belvédère, Tunis (TUNISIE) 2Département de Géologie, Faculté des Sciences de Tunisie, 1060 Belvédère, E-mail: [email protected] Tunis, (TUNISIE) Received: 10th October, 2006 Accepted: 9th November, 2006 Web Publication Date : 27th December, 2006 ABSTRACT KEYWORDS The study of Djebel Oust Berriasian clays shows an abundance of illite Berriasian; (66%), the presence of kaolinite (16%), a fair amount of interstratified Clays; illite/smectite (10%) and chlorite (8%). The geochemical analysis proves Mineralogy; that these clays are siliceous, Ca-rich and aluminous. The iron rate is 4.7%. Geochemistry; The geotechnical study indicates that these clays are little to fairly plastic, Geotechnical; and adapt fast to drying. Also, the study shows that firing shrinkage is little. Ceramic tests. In the light of these results, these clays could be used in manufacturing of the ceramic pieces. 2006 Trade Science Inc. - INDIA INTRODUCTION tectonic settings. Indeed, they studied the geological series of northern Tunisia and in particular those of In this study, we are focusing on the physical- J.Oust[1] , tried to explain Jurassic extrusions and their chemical and geotechnical characterization of relationships to the lower-Cretaceous series[2-3]. They Berriasian clays which occupy east, west and northern produced the geological map of Bir M’echerga to west sides of Djebel Oust. The latter is situated 35 the 1/50000 which covers all the series of J.Oust[4-5] km West-South of Tunis and 20 km West North of and carried out a biostratigraphic study of the series Zaghouan. The series of the lower-Cretaceous of J. of the lower-Cretaceous of J.Oust [6-8]. They established Oust and namely those of Berriasian clays have risen a correlation between the series of the lower- a great amount of discussion and interest among Cretaceous of the Eastern Atlas while referring to geologists since a long time. They were the subject biostratigraphic data[9] and established a detailed of various studies: age, depositional environment and zonation of the series of the lower-Cretaceous by 170 Berriasian. Clays MSAIJ, 2(6) December 2006 Full Paper N Bizerte N Tunis Jandouba Ain Askar M Zaghouan editrranean Village of DJebel Oust Sousse sea Kasserine Sfax Minor Road N°62 Gafsa 0 100km N°2 Main-Road Gabes Bir M’Cherga Aptian-Albian clays Barremian level calcareous Berriasian clay Main-Road N°3 Jurassic Calcaire fault Railway Valley of Meliane Rood Field of study Figure 1: The geographic situation of studied sector.Extacted from the simplified geological map of Bir M’Cherga N°28 improving the former subdivisions[10]. dried and fired samples, respectively. The clays intended for the industrial tests were MATERIALS AND METHODS dried at 110°C, and later finely crushed. The preparation of ceramic pieces necessitates the mixture The X-ray diffractometer used in this study is a of two kilograms of clay with 7 % of water. For Philips X’ Pert Pro system. The wave length (λ) is each mixture, we make 20 earthenware squares, 1.5418Å (Cu Kα). The generator of the X-Ray each one had the following dimensions: 100 mm * diffractometer operates at 40Kv and 40 mA. The cation 50 mm * 7 mm, and was pressed at 250 bars. Initially, exchange capacity is measured with standard acetate we dried them at ambient temperature during four ammonium procedure[11]. The major element hours. Then, we dried them at 30°C, after that at compositions are determined by atomic absorption. The 50°C and finally at 110 °C until we have the constant differential thermal analysis coupled with weight. The firing was carried out in an electric thermogravimetry (DTA/TG) was obtained with a furnace at different temperatures (900, 950, 1000 SETRAM type 124. The expansion and firing and 1050°C) with a rise of 300°C per hour. For each shrinkage were measured using dilatometer Adamel mixture, we carried out the firing of five ceramic Lhomargy type BI. The samples were heated from pieces[12-14]. ambient temperature to 900°C. The rate of temperature rise was 10°/min. The parameters of plasticity (liquid RESULTS AND DISCUSSION limit (LL), plastic limit (PL) and index plasticity (IP), IP = LL - PL) were determined in accordance with the Clay characterization French Standard NF P 94-051. Drying behaviour was 1. X-ray diffraction study studied using barelatograph D124. The drying and firing shrinkage were evaluated using the formulas: | X-ray diffraction patterns of the studied Berriasian (l – l ) / l |x 100 and| (l – l ) / l |x 100, respectively. clays (Figure 1) show that the percentages of the crude g d g f d d sample and the fraction below 2µm do not present a Where lg, ld and lf are the measured length of green, MaterialsAn IndianScience Journal MSAIJ, 2(6)December2006 % foreachmineral(TABLE 1). interstratified illite/smectite, withapercentageof9 There aresimilarquantities ofchloriteand mineral witharatevaryingbetween11%and24%. between 57%and71%.Kaoliniteisthesecond dominated byillitewithapercentageoscillating 43%and63%.The between crudevaries sampleis oscillates between25%and42%.The<2 between 12%and25%ofthecalcitewhich, presence oftheproportionsinquartzthatvaried of thefractionbelow2 semicalculation Indeed,quantitative Berriasian clays. noticeable changealongthegeologicalseriesof WBe 2 WBe EBe 1 WBe 3 WBe WBe1 14.22Ch 14.17 13.97 11.89 I/S 14.201 14.13Ch 14.01Ch 9.96 I 9.93 11.18 I/S 11.31 11.88 I/S 11.81 12.01 7.83 I/S 9.98 I 9.94 I 9.94 11.97I/S µ 9.87 10.18 9.99 I m allowedustoshowthe 6.97 7.88 I/S Figure 2:RXDiffractogmsofJ.OustBerriasianclays 7.08 K 7.08K 6.97 6.99 7.21 K 6.97 7.11 K 4.45 Phy 4.98 I 4.45Phy 4.98 I 4.46 Phy 4.21Q 4.45 Phy 5.00 I 4.98 I 4.23 Q 4.22 Q 4.22 Q 3.5 Phy 3.5 Ph 3.5Phy y µ 3.53 K 3.33Q 3.53K m fraction 3.33Q 3.33I 3.33 I 3.33Q 3.55 K 3.33Q 3.58 K 3.33 I Salah Mahmoudietal. 171 3.02C 3.02C 3.33 I 3.02C 3.01C LG LG LC LN LC LN LG LC LN LG LC LN 2.55 Phy 2.55Phy 2.55 Phy 2.48C 2.55 Phy 2.48 C 2.48 C nating between34.47% and 46.12%.Thepercent- 11.27% and14.03% proportions ofsilicaalter- shows thattheycontain aluminavaryingbetween 2. Chemicalstudy 2.48 C W Be3 W Be2 12 W Be1 25 25 20 27 63 33 48 58 25 47 61 14 71 7 15 6 10 4 18 9 E Be1 15 42 43 69 11 20 0 TABLE 1: composition(wt.%) Mineralogical TABLE 2.27Q 2.27 Q 2.27Q The analysisof chemical Berriasian clays J.Oust 2.12 Q 2.12Q 2.12Q 2.12 Q 1.90 C Qz Ca Qz Ca Phy I K I/Sm Ch 1.86 C Whole sample sample Whole 1.90C 1.90 C 1.86 C 1.86 C 1.86 C 1.81 Q 1.81 Q 1.81 Q 1 1.66 Q 1.66Q 1.59 C 1.59 C 1.59 C 1.59 C Materials Science Materials Science I/S - interstratified Ch -K chlorite -I kaolinite C - illite Q - calcite -Phy - quartz phyllosilicates F F <2 F F F ull ull ull ull ull µ illite/smectite m Fraction m Fraction An Indian Journal An Indian P P P P P aper aper aper aper aper 172 Berriasian. Clays MSAIJ, 2(6) December 2006 Full Paper TABLE 2: Chemical composition (wt. %) In aqueous solution the phyllosilicates can E Be 1 W Be 1 W Be 2 W Be 3 exchange certain ions with others, Thus according SiO2 34.47 45.15 46.12 43.75 to the nature of clay, the interlayer cations can Al2O3 12.70 11.27 14.03 12.58 substitute with other compensation cations of load Fe2O3 4.10 4.27 5.38 5.19 to balance the electric charge of 100 g clay. The CaO 20.66 16.49 13.12 15.21 results described in TABLE 3 show that the values MgO 1.71 0.68 1.02 1.20 of the cation exchange capacities are low and does Na2O 2.59 1.60 1.76 1.97 not exceed 12. This is explained by the presence of K2O 3.02 2.56 2.43 2.33 impurities (carbonates and silica), the abundance of Loss of ignition 20.63 17.84 16.01 17.54 clay minerals formed primarily by illite and kaolinite, and the absence of clay minerals with strong cation ages of iron vary between 4.10% and 5.19%. The exchange capacities such as smectites and vermiculites. amount of CaO varies between 13.12% and 20.66%. This result is in agreement with the X-ray diffraction. The existence of the zones containing K O near to 2 The cation exchange capacities the crude samples rose 3.02% (TABLE 2) testifies the presence of illite. due to the elimination of carbonates. This has been already ascertained in the mineralogical analysis. Ceramic properties 3. IR-spectroscopy 1. Plasticity Figure 3 depicts the results obtained from the The test of plasticity of J.Oust Berriasian clays infrared spectra of Berriasian clays.

Load more