Hostname: page-component-7bb8b95d7b-pwrkn Total loading time: 0 Render date: 2024-09-18T12:27:02.635Z Has data issue: false hasContentIssue false
  • English
  • Français

Influence of metakaolinization temperature on the formation of zeolite 4A from kaolin

Published online by Cambridge University Press:  09 July 2018

S. Chandrasekhar
S. Chandrasekhar*
Affiliation:
Clays and Clay Minerals Section, Regional Research Laboratory, Thiruvananthapuram - 695019, India
Get access Rights & Permissions [Opens in a new window]

Abstract

Kaolin has been used as an alternative cheap raw material for the synthesis of zeolite 4A. Two steps are involved in the reaction: (1) dehydroxylation of kaolin at 550–900°C to form an activated X-ray amorphous material called metakaolin; (2) hydrothermal treatment of metakaolin with aqueous alkali to form the zeolite. The inherent colouring impurities in kaolin, especially the Fe minerals, affect the brightness of metakaolin and the resultant zeolite. The dehydroxylation temperature is found to have a significant influence on the kinetics of zeolite formation as well as on the brightness of zeolite. The present investigation deals with the preparation of metakaolins from a good quality kaolin at different temperatures and their characterization by XRD, IR, TGA, MAS NMR and brightness measurements. Hydrothermal reactions of these metakaolins with aqueous alkali have been conducted. The residual Fe in the mother liquor has been estimated. The improvement in brightness and change in reactivity of the metakaolin, difference in the kinetics of its conversion to zeolites and dissolution of Fe during zeolite formation have been correlated with the calcination temperature. A calcination temperature of 900°C (1 hr) is the optimum for this clay to change into a reactive metakaolin which gives detergent grade zeolite 4A of high crystallinity and maximum brightness.

Type
Research Article
Information
Clay Minerals , Volume 31 , Issue 2 , June 1996 , pp. 253 - 261
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bachiorrini, A. & Murat, M. (1986) Infrared absorption spectroscopy applied to the characterisation of the amorphisation state of metakaolinite. C. R. Acad. Sc. 303, Ser. II, 1783-1786.Google Scholar
Barrer, R.M. (1978) Zeolites and Clay Minerals as Sorbents and Molecular sieves. Academic Press, London.Google Scholar
Barrer, R.M. (1982) Hydrothermal Chemistry of Zeolites. Academic Press, London.Google Scholar
Breck, D.W. (1974) Zeolite Molecular Sieves - Structure, Chemistry and Uses. Pp. 313-320 and 731-738. John Wiley & Sons Inc, New York.Google Scholar
Brown, I.W.M., Mackenzie, K.J.D. & Meinhold, R.H. (1985) Outstanding problems in the kaolinite-mullite reaction sequence investigated by 29Si and 27Al solid state NMR: High temperature transformation of metakaolinite. J. Am. Ceram. Soc., 68, 298–301.Google Scholar
DEGUSSA, (1987) Technical Bulletin Pigments Wessalith for Detergents No.71. Germany.Google Scholar
Dyer, A. (1988) An Introduction to Zeolite Molecular Sieves. John Wiley & Sons, New York.Google Scholar
Ferris, A.P. (1981) Improvements in or relating to zeolites. Br. Pat. 1, 603,084.Google Scholar
Fitton, R.C. & Fiore, B.A. (1978) Preparation of Improved Zeolites. US Pat. 4, 075,280.Google Scholar
Hinckley, D.N. (1963) Variability in “Crystallinity” values among the kaolin deposits of the coastal plains of Georgia and South Carolina. Clays Clay Miner. 11, 229–235.Google Scholar
Howell, P.H., Acara, N.A. & Towne, M.K. Jr. (1965) Production of molecular sieve adsorbents from kaolin minerals. Br. Pat. No, 980,891.Google Scholar
Jepson, W.B. (1988) Structural Fe in kaolinites and in associated ancillary minerals. Pp. 467–536 in: Iron in Soils and Clay Minerals (Stucki, J.W., editor), D. Riedel Publishing Company, Netherlands.Google Scholar
Mackenzie, K.J.D., Brown, I.W.M., Meinhold, R.H. & Bowden, M.E. (1985) Outstanding problems in the kaolinite - mullite sequence investigated by 29Si and 27Al solid state NMR: 1 metakaolinite. J. Am. Ceram. Soc., 68, 293–297.Google Scholar
Madani, A., Aznar, A., Sanz, J. & Serratosa, J.M. (1990) 29Si and 27Al NMR study of zeolite formation from alkali leached kaolinites – influence of thermal preactivation. J. Phys. Chem. 94, 760–765.Google Scholar
Meinhold, R.H., Mackenzie, K.J.D. & Brown, I.W.M. (1985) Thermal reactions of kaolinite studied by solid state 29Si and 27Al NMR. J. Mat. Sci. Lett., 4, 163–166.CrossRefGoogle Scholar
Mole, V.C. (1989) Improved Zeolite Builders for Detergents. PhD thesis, Univ. London, UK.Google Scholar
Murat, M. & Bachiorrini, A. (1982) Correlations entre l'etat d'amorphisation et l'hydraulicite du metakaolin. Bull. Mineral. 105, 543–555.Google Scholar
Murat, M. & Driouche, M. (1988) Conductimetric investigations on the dissolution of metakaolinite in dilute hydrofluoric acid. Structural implications. Clay Miner. 23, 55-67.Google Scholar
Murat, M., Mathurin, D. & Chbihiel, M. (1987) Enthalpie de dissolution de differentes kaolinites et metakaolinites dans l'acide fluorhydrique, Influence des caracteristiques crystallochimiques. Thermochim. Acta, 122, 79–85.Google Scholar
Murat, M., Amokrane, A., Bastide, J.P. & Montanaro, L. (1992) Synthesis of zeolites from thermally activated kaolinite – some observations on nucleation and growth. Clay Miner. 27, 119–130.Google Scholar
Percival, H.J., Duncan, J.F. & Foster, P.K. (1974) Interpretation of the kaolinite-mullite reaction sequence from infra red absorption spectra. J. Am. Ceram. Soc. 57, 57–61.CrossRefGoogle Scholar
Rees, L.V.C. & Chandrasekhar, S. (1993) Formation of zeolites from the system Na2O-SiO2-Al2O3-H2O in alkaline medium (pH 10). Zeolites, 13, 524–533.Google Scholar
Rocna, J. & Klinowski, J. (1990) Solid state NMR studies of the structure and reactivity of metakaolinite. Angew. Chem. Int. Ed. Engl. 29, 553–554.Google Scholar
Rocha, J., Klinowski, J. & Adams, J.M. (1991) Synthesis of Zeolite 4A from metakaolinite - revisited. J. Chem. Soc. Faraday Trans. 87, 3091–3097.Google Scholar
Stoch, L. (1987) Iron in kaolins - Mineralogical crystallo-chemical and technological aspects. Interceram. 6, 21-25.Google Scholar