A mild conditions synthesis route to produce hydrosodalite from kaolinite, compatible with extrusion processing

A. Marsh, A. Heath, P. Patureau, M. Evernden, P. Walker

Research output: Contribution to journalArticlepeer-review

34 Citations (SciVal)


Hydrosodalites are a family of zeolitic materials which have a diverse range of possible applications such as water desalination. Typical synthesis methods are relatively complex, using hydrothermal production and pre-processing and it is desirable to use lower energy and more cost-effective processing routes. For the first time, a low temperature, non-hydrothermal synthesis procedure for hydrosodalites, compatible with extrusion processing, is demonstrated. Kaolinite precursor, without calcination, was activated with a sodium hydroxide solution and formed at a workability consistent with extrusion. The cured samples were characterised using a range of advanced analytical techniques including PXRD, SEM, TGA, 27Al and 29Si-MAS-NMR, and FTIR to confirm and quantify conversion of the precursor to product phases. The synthesis consistently formed a 8:2:2 basic hydroxysodalite phase and the reaction was shown to follow a largely linear relationship with Na:Al until full conversion to the hydrosodalite phase was approached. The hydrosodalite became more ordered for Na:Al ≥ 1. There is good agreement between quantitative measurements made using PXRD, TGA and 29Si-MAS-NMR methods, providing confidence in the results. It has been shown that it is possible to synthesise hydrosodalite materials in a consistent and predictable manner, using non-hydrothermal methods, at the viscosity used for extrusion processing. This novel processing route could reduce production costs, production impacts and open up new applications for this important family of materials.
Original languageEnglish
Pages (from-to)125-132
Number of pages8
JournalMicroporous and Mesoporous Materials
Early online date16 Jan 2018
Publication statusPublished - 1 Jul 2018


  • Hydrosodalite
  • Kaolinite
  • Alkali activation
  • Extrusion

ASJC Scopus subject areas

  • Materials Chemistry
  • Inorganic Chemistry
  • Civil and Structural Engineering


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