Bulk modulus of basic sodalite, Na8[AlSiO4]6(OH)2·2H2O, a possible zeolitic precursor in coal-fly-ash-based geopolymers

Jae Eun Oh, Juhyuk Moon, Mauricio Mancio, Simon M. Clark, Paulo J. M. Monteiro

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Synthetic basic sodalite, Na8[AlSiO4] 6(OH)2•2H2O, cubic, P43n, (also known as hydroxysodalite hydrate) was prepared by the alkaline activation of amorphous aluminosilicate glass, obtained from the phase separation of Class F fly ash. The sample was subjected to a process similar to geopolymerization, using high concentrations of a NaOH solution at 90 °C for 24 hours. Basic sodalite was chosen as a representative analogue of the zeolite precursor existing in Na-based Class F fly ash geopolymers. To determine its bulk modulus, high-pressure synchrotron X-ray powder diffraction was applied using a diamond anvil cell (DAC) up to a pressure of 4.5 GPa. A curve-fit with a truncated third-order Birch-Murnaghan equation of state with a fixed K'o = 4 to pressure-normalized volume data yielded the isothermal bulk modulus, K o = 43 ± 4 GPa, indicating that basic sodalite is more compressible than sodalite, possibly due to a difference in interactions between the framework host and the guest molecules. © 2010 Elsevier Ltd.
Original languageEnglish (US)
Pages (from-to)107-112
Number of pages6
JournalCement and Concrete Research
Issue number1
StatePublished - Jan 2011
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-l1-004021
Acknowledgements: This publication was based on work supported in part by Award No. KUS-l1-004021 made by the King Abdullah University of Science and Technology (KAUST) and the by NIST Grant 60NANB10D014. The work for the Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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