Studying the Effect of Adding Doekhla kaolin Clay and Alumina to Iraqi Bauxite on Some Physical and Mechanical and Thermal Properties


  • Alaa A. Abdul-Hamead Department of Materials Engineering / University of technology


The aim of this work is to produce samples from Iraqi raw materials like Husyniat Bauxite (raw and burnt) and to study the effect of some additives like white Doekhla kaolin clays and alumina on that material properties were using sodium silica as a binding material. Five mixtures were prepared from Bauxite (raw and burnt) and kaolin clays, with an additive of (40) ml from sodium silica and alumina of (2.5, 5, 7.5,10 wt %) percentage as a binding material. the size grading was through sieving. The formation of all specimens was conducted by a measured gradually semi-dry pressing method under a compression force of (10) Tons and humidity ratio ranging from (5-10) % from mixture weight. Drying all specimens was done and then they were burnt under (1200)°C temperatures according to a burning program which raised the temperature (5)°C per minute and then the soaking interval. Some tests such as the  physical, mechanical and thermal test were connected on the testing results for the specimens indicated that the raw materials with fine size range and high temperature gave specimens a thermal phase with  higher percent of Mullit in comparison with coarse size.  Bulk density values, coefficient of longitudinal and hardness increase with porosity and ratio of water absorption values decrease. Also, results show that Alumina with Bauxite gives it stiffens because of the increase of the mullite phase which is characterized by high mechanical and thermal properties especially thermal conductivity. Results show that the best thermal and mechanical properties are found in the fifth mixture (X5) which contains a ratio of about (10) % of Al2O3 .        


Download data is not yet available.


[1] Hill, W.B. , "Refractory Grade calcined Bauxite from china", Interceram , 23 (3) 314-315 (1979).
[2] Rothenbry, G.B. "Refractory Materials", 11st ed. Park Ridge, New Jersy, USA , PP.(1-2 , 9-10 , 81-871), (1976).
[3] الطائي، محمد حيدر. الرمضاني، خيرية 1981: (تحسين نوعية الطابوق الناري الطيني)، مركز بحوث البناء النشرة العلمية صفحة 65، 81، 59.
[4] Kingery,W.D.,Introduction to Ceramic. John. Wiley and Sons,Inc., New York1967,p231-275.
[5] Singer, F. & singer, S, Industrial Ceramics. Chemical publ. COM.INC, .(1971).
[6] Cameron, W.E., Composition and cell Dimensions of Mullite, J.Am. Ceram. Soc. Bull., 1977,56(11):1003-1007.
[7] ASTM ,"Annul book of ASTM Standards ",1988, ASTM, (ASTM C326-76), (ASTMC 373 – 72), ASTM C438 – 71) ,*Withdrawn Standards Until 2006.
[8] Salmang, H., Ceramics; physical and chemical Fundamentals. Butter Worths, London. ,1961, 380P.
[9] Grimshaw , R.W., the Chemistry and Physics of Clay and Allied Ceramic Materials .4th ed ernest benn limited, London, ( 1971) , 1024 p .
[10] Temuujin, J., Okada, K., Mackenzie., K.J., Effect of Mechanochemical Treatment on the Crystallization Behaviour of Diphasic Mullite gel. Ceramics International , 1999,25:85-90.
[11] Ashbrook ,S.E. Manus ,J.M. ,Mackenzie , K.J.. and Wimperis ,S.,Multiple _Quantum and Croos_palarized AL 27 Masnmr of Mechanically Treated Mixture of Kaolinite and Gibbsite .J. Phy.Chem., 2000 ,104(27):6408-6416.
[12] Li ,d.x. and Thomson, W.J., Mullite Formation Kinetics of a Single-phase Gel .J.Am. Ceram. Soc., 1990, 73(4): 964-969.
[13] Aksay, I.A. & Pask.J.A, Stable and Metastable Equlibria in the System Al2O3 –SiO2 J.Am. Ceram. Soc. 1975,58(11-12):507-512.
[14] النعيمي, محمد احمد., تاثير نوعية السيلكا في الصفات الفيزياوية والميكانيكية للاجسام السيراميكية المستخدمة كمواد بناء, رسالة ماجستير /جامعة بغداد(1996).
[15] Mizuno, M.,Microstructure, Microchemistry, and Flexural Strength of Mullite Ceramics. J.Am. Ceram. Soc., 1991:74 (12): 3017-3022.
[16] Abdul Kareem, I.A., 1996: The Technological proportion of Mullite Prepared from Iraqi Raw Materials Unpubl. M. Sc. Thesis, Univ. of Technology-Baghdad.
[17] Huang, X., Hwang, J.Y and mutsuddy, B.C., Properties of Mullite Synthesized from Fly Ash and Alumina Mixterceram., 1995, 44(2): 65-71.
[18] Warrir, K. G. K., Mukundan, D., Pillai, P. K. and Damodran, A. D., Particle size of quartz and the vitrification of porcelain bodies. Interceramic. , 1989,38 (5): 19 – 21.
[19] Kukolev, V. inments, i.,Semchenko, G.D.,Belukra,P.G., Stanilov , B.E. and Primachnko,V.V ., Dense Ladle Brick with Kaoline Bond. Refractories, j., 1972 43(4): 216-218.
[20] الهيتي, مراتب صالح1987: تقييم خامات منطقة سماحات لأستخدامها في صناعة الطابوق الناري. رسالة ماجستير , الجامعة التكنولوجية.
[21] Worral, W.E., Clay and Ceramic Raw Materials. Applied Science Pubisher, 1 ed., London, 1965.
[22] Chen, C.Y., Lan, G.S.and Tuan, W.H., Preparation of Mullite by the Reaction Sintering of Kaolinite and Alumina. ,J. Europ. Ceram. Soc., 2000,20(14-15).
[23] Barsoum, M.W., Fundamentals of Ceramics,Published by Mc Graw-Hill, International, 1997.
[24] Warshaw, S.I., Seider, R.,Comparison of Strength of Triaxial Porcelains Containing Alumina and Silica. J.Am. Ceram. Soc., 1967, 50(7): 337-343.
[25] Kingery, W. D., Bowen, H. K. and Uhlmann, D. R., Introduction to Ceramic. 2nd ed, John. Wiley and Sons, New York, 1976, 1032p




How to Cite

Abdul-Hamead, A. A. (2019). Studying the Effect of Adding Doekhla kaolin Clay and Alumina to Iraqi Bauxite on Some Physical and Mechanical and Thermal Properties. Al-Khwarizmi Engineering Journal (Alkej), 7(1), 95–105. Retrieved from