Synthesis of Zeolite A from Iraqi Natural Kaolin Using a Conventional Hydrothermal Synthesis Technique




Zeolite A, Kaolin, Metakaolin, Hydrothermal synthesis.


The synthesis of zeolite materials by hydrothermal transformation of kaolin using a conventional hydrothermal method was investigated. Different analytical techniques were used to characterize the starting kaolin and produced zeolite A samples, including scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray diffraction (XRD), x-ray fluorescence (XRF), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR) spectroscopy. The synthetic zeolite type A was obtained after activation of kaolin and metakaolin followed by different thermal and chemical treatments. The metakaolinization phase was achieved by calcining the kaolin in air at 600°C for 3 hours, a much lower temperature than previously reported in the literature. Metakaolin was treated with 3 M sodium hydroxide solution at a ratio of 1:5 and, using stainless steel autoclaves with teflon liners, heated the mixture to 200°C in a microwave for 24 hours. The results from this synthesis route showed that zeolite A with a cubic crystal habit has been successfully synthesized.


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Author Biographies

  • Ali Mohammed Salih, Department of Geology, Kurdistan Institution for Strategic Studies and Scientific Research, Sulaimani, Kurdistan Region - F.R. Iraq

    Dr. Ali Mohammed Salih; Head of  Geology Department, Kurdistan Institution for Strategic Studies and Scientific Research (K.I.S.S.R.), teaching environmental sciences and EHS course. Working and leading a team in environmental health and safety department and research center. He has completed PhD program and MSc course at university of Wolverhampton in the UK.  The previous work and study enabled him to re-focus onto the application of technological solutions to environmental problems.  Building No. 10, Alley 60, Gullabax 335, Shorsh Street, Sulaimaniyah, Kurdistan Region Iraq,

  • Craig Williams, Department of Chemistry and Forensic Science, School of Biology, Faculty of Science and Engineering, University of Wolverhampton, UK

    Craig has over 25 years’ experience within the zeolite community. After his PhD studies, Craig worked as a research fellow at Edinburgh and Liverpool Universities. In 1990 he joined the staff at Wolverhampton and in 1993 established the meso and microporous research group to study the problems involved in zeolite synthesis and isomorphous substitution. This group now has 27 successfully completed PhD studies. He is an internationally leading figure in the synthesis of metal substituted zeolite frameworks. To date five patents and over 80 publications on various aspects of zeolite science in refereed journals have been produced. In 1999 he was elected a Fellow of the Royal Society of Chemistry (RSC) and has served as Secretary and Chair of the Analytical Division of the Midlands Region of the RSC and Secretary of the Industrial Inorganic Chemicals Sector of the RSC. He is also immediate past Secretary of the British Zeolite Association (BZA).

  • Polla A Khanaqa, Kurdistan Institution for Strategic Studies and Scientific Research (KISSR), Sulaimani, Kurdistan Region – F.R. Iraq

    Prof. Dr. rer. nat. Geol. Polla A. Khanaqa; Founder & President of: Kurdistan Institution for Strategic Studies and Scientific Research (K.I.S.S.R.), scientist with experiences as a University lecturer and with management experiences, and competences in the field of higher education and scientific research. He pursued his education in Germany and he obtained a Ph.D. in the field of Geology at Georg-August University of Göttingen in in 1997. Five years after completing his PhD, Professor Khanaqa obtained his post doctorate at the same University. Building No. 10, Alley 60, Gullabax 335, Shorsh Street, Sulaimaniyah, Kurdistan Region Iraq


Ackley M.W., Rege S.U. and Saxena H. (2003) Application of natural zeolites in the purification and separation of gases. Microporous and Mesoporous Materials, 61 (1–3), 25 – 42.

Adamczyk, Z. and Bialecka, B. (2005) Hydrothermal synthesis of zeolites from polish coal fly ash. Polish Journal of Environmental Studies, 14(6), 713 – 719.

Alkan, M., Hopa, C., Yilmaz, Z. and Guler, H. (2005) The effect of alkali concentration and solid/liquid ratio on the hydrothermal synthesis of zeolite NaA from natural kaolin. Microporous and Mesoporous Materials, 86, 176 – 184.

Alvarez-Ayuso, E., Garcia-Sanchez, A. and Querol, X. (2003) Purification of metal electroplating waste waters using zeolites. Water Research, 37(20), 4855 – 4862.

Ayele, L., Perez-Pariente, J., Chebude, Y. and Diaz, I. (2015) Synthesis of zeolite A from Ethiopian kaolin. Microporous and Mesoporous Materials, 215, 29 – 36.

Bellotto, M., Gualtieri, A., Artioli, G., and Clark, S.M. (1995) Kinetic study of the kaolinite-mullite reaction sequence. Part I: kaolinite dehydroxylation. Physics and Chemistry of Minerals, 22 (4), 207–214.

Deer, W.A., Howie, R.A., and Zussman, J. (1992) An introduction to the rock-forming minerals. 2nd ed. Harlow: Longman.

Doaa, M. and Mohamed, S. (2014) Removal of Pb2+ from water by using Na-Y zeolites prepared from Egyptian kaolins collected from different sources. Journal of Environmental Chemical Engineering, 2, 723 – 730.

Dyer, A. and Zubair, M. (1998) Ion-exchange in Chabazite. Microporous and Mesoporous Materials. 22, 135 – 150.

Frost, R.L., Horváth, E., Makóc, E., Kristóf, J. and Rédey, A. (2003) Slow transformation of mechanically dehydroxylated kaolinite to kaolinite - an aged mechanochemically activated formamide - intercalated kaolinite study. Thermochimica Acta, 408, 103 – 113.

Frost, R.L., Mako, E., Krsitof, J. and Kloprogge, J.T. (2002). Modification of kaolin surfaces through mechanochemical treatment - a mid-IR and near-IR spectroscopic study, Spectrochimica Acta Part A. Molecular and Biomolecular Spectroscopy, 58, 2849 – 2859.

Gougazeh, M. and Buhl, C.H. (2010) Geochemical and Mineralogical Characterisation of the Jabal Al-Harad Kaolin Deposit, Southern Jordan for its Possible Utilization Clay Miner. Mineralogical Society, 45 (4), 281–294.

Inglezakis, V.J., Loizidou, M.M. and Grigoropoulou, H.P. (2004) Ion exchange studies on natural and modified zeolites and the concept of exchange site accessibility. Journal of Colloid and Interface Science, 275(2), 570 – 576.

Kakali, G., Perraki, T., Tsivilis, S., and Badogiannis, E. (2001). Thermal treatment of kaolin: the effect of mineralogy on the pozzolanic activity. Applied Clay Science, 20, 73 – 80.

Kovo, A.S. and Holmes S.M. (2010) Effect of aging on the synthesis of kaolin-based zeolite Y from Ahoko Nageria using a novel metakaolnization technique. Journal of dispersion Science Technology, 31, 442 – 448.

Kristof, J., Mink, J., Horvath, E. and Gabor, M. (1993). Intercalation study of clay minerals by Fourier transform infrared spectrometry. Vibrational Spectroscop., 5, 61 – 67.

Lambert, J.F., Minman, W.S. and Fripiat, J.J. (1989). Revisiting kaolin dehydroxylation: A silicon-29 and aluminum-27 MAS NMR study. Journal of the American Chemical Society, 111, 3517– 3522.

Liu, Q., Spears, D.A. and Liu, Q. (2001). MAS NMR study of surface-modified calcined kaolin. Applied Clay Science 19, 89 – 94.

Miao,Q., Zhou, Z., Yang, J., Lu, J., Yan, S. and Wang,J. (2009) Synthesis of NaA zeolite from kaolin source. Frontiers of Chemical Engineering in China, 3(1) 8 – 11.

Mousa, G. and Buhl, J. (2014) Synthesis and Characterisation of zeolite A by hydrothermal transformation of natural Jordanian kaolin. Journal of the Association of Arab Universities for Basic and Applied Sciences (2014) 15, 35 – 42.

Murat, M., Amorkrane, A., Bastide, J.P. and Montanaro, L. (1992) Synthesis of zeolites from thermally activated kaolinite. Some observations on nucleation and growth. Clay Minerals, 27, 119 – 130.

Nesse W.D. (2000) Introduction of mineralogy, Oxford University Press. UK.

Novembre, D. Sabatino, B.D. and Gimeno, D. (2011) Synthesis and Characterisation of Na-X, Na-A and Na-P zeolites and hydroxysodalite from metakaolinite Clays. Clay Minerals, 46, 339 –354.

Pandey, P., Sambi, S.S., Sharma, S.K. and Singh, S. (2009) Batch Adsorption Studies for the Removal of Cu (II) Ions by ZeoliteNaX from Aqueous Stream. Proceedings of the World Congress on Engineering and Computer Science, I, San Francisco, USA.

Paul W.S. (2003). "Kaolin". New Georgia Encyclopedia. Retrieved 2008-08-01.

Perraki, T. and Orfanoudaki, A. (2004) Mineralogical study of zeolites from Pentalofos area. Applied Clay Science, 25, 9.

Pohl, Walter L. (2011). Economic geology: principles and practice: metals, minerals, coal and hydrocarbons. Introduction to formation and sustainable exploitation of mineral deposits. Chichester, West Sussex: Wiley-Blackwell. p. 331. ISBN 978-1-4443-3662-7.

Qiu, G., Jiang, T., Li, G., Fan, X. and Huang, Z. (2004) Activation and removal of silicon in kaolin by thermochemical process. Journal of Metallurg., 33,1211 – 28.

Querol, X., Plana, F., Alastuey, A., Lopez-Soler A. (1997) Synthesis of Na-zeolites from fly ash. Fuel, 76, 793 – 799.

Ramos R.L., Armenta G.A., Gutierrez L.V.G., Coronado R.M.G., and Barron J.M. (2004) Ammonia exchange on clinoptilolite from mineral deposits located in Mexico. Journal of Chemical Technology and Biotechnology, 79, 651 – 657.

Rios, C.A., Williams, C.D. and Maple M.J. (2007) Synthesis of zeolites and zeotypes by hydrothermal transportation of kaolin and metakaolin, BISTUA, 5 (1), 15–26.

Saikia, N.J., Bharali, D.J., Sengupta, P., Bordoloi, D., Goswamee, R.L., Saikia, P.C. and Bothakur, P.C. (2003) Characterisation, beneficiation and utilization of a kaolin clay from Assam, India. Applied Clay Science, 24, 93 –103.

Sinha, P.K., Paniker, P.K. and Amalraj, R.V. (1995) Treatment of radioactive liquid waste containing caesium by indigenously available synthetic zeolites: A comparative study. Waste Management, 15, 149 – 157.

Szoztak, R. (1998) Molecular Sieves: Principles of Synthesis and Identification.2nd ed. Blackie Academic and Professional: London.

Tanaka, H., Miyagawa, A., Eguchi, B., Hino V.R. (2004) Synthesis of a pure-form Zeolite A from coal fly ash by dialysis. Journal of Industrial and Engineering Chemistry, 43, 6090 – 6094.

Ugal, J.R, Hassan,K.H. and Inam H. Ali(2010) Preparation of type 4A zeolite from Iraqi kaolin: Characterisation and properties measurements, Journal of the Association of Arab Universities for Basic and Applied Sciences, 9, 2 – 5

Valcke, E., Engels, B. and Cremers, A. (1997) The use of zeolites as amendments in radiocaesium- and radiostrontium-contaminated soils: A soil-chemical approach. Part II: Sr-Ca exchange in clinoptilolite, mordenite and zeolite A. Zeolites, 18, 212 – 217.

Van der Marel, H.W. and Beutelspacher, H. (1976) Atlas of Infrared Spectroscopy of Clay Minerals and Their Admixtures, 1st ed. Elsevier: Amsterdam.

Walek, T.T., Saito, F. and Zhang, Q. (2008) the effect of low solid/liquid ratio on hydrothermal synthesis of zeolites from fly ash. Fuel, 87, 3194 – 3199

Wang, C.F., Li, J.S., Wang, L.J., Sun, X.Y. (2008) Influence of NaOH concentrations on synthesis of pure-form zeolite A from fly ash using two-stage method, Journal of Hazardous Materials, 155, 58 – 64.

Zhao, H., Deng, Y., Harsh, J.B., Flury, M. and Boyle, J.S. (2004) Alteration of kaolin to cancrinite and sodalite by simulated hanford tank waste and its impact on cesium retention. Clays and Clay Minerals, 52, 1 – 13.





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How to Cite

Synthesis of Zeolite A from Iraqi Natural Kaolin Using a Conventional Hydrothermal Synthesis Technique. (2020). UKH Journal of Science and Engineering, 4(2), 11-23.