skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Geopolymerisation Kinetics. 1. In situ Energy-Dispersive X-ray Diffractometry

Abstract

In situ energy-dispersive X-ray diffractometry, using a polychromatic synchrotron beam and a 'laboratory-sized' sample, is used to provide a direct measurement of the kinetics of geopolymerisation. The effects of sample SiO{sub 2}/Al{sub 2}O{sub 3} ratio, Na/(Na+K) ratio and reaction temperature are investigated. The results obtained support recent propositions that the initial gel phase formed during geopolymerisation is later transformed to a second, probably more-ordered gel phase, and provide detailed information regarding the rate of formation of the first gel phase during the first 3 h of reaction. Increasing the SiO{sub 2}/Al{sub 2}O{sub 3} ratio generally decreases the initial rate of reaction, with the highest SiO{sub 2}/Al{sub 2}O{sub 3} ratio samples showing what appears to be a pause in the reaction corresponding roughly to the solidification of the geopolymeric binder. Mixed (Na,K)-aluminosilicate geopolymers with moderate SiO{sub 2}/Al{sub 2}O{sub 3} ratios behave similarly to pure Na- or K-aluminosilicate compositions of higher SiO{sub 2}/Al{sub 2}O{sub 3} ratio. Fitting a simplified first-order rate expression to the overall reaction process at different temperatures allows the calculation of an effective overall activation energy, which may be useful in comparing geopolymerisation of slurries with different compositions.

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
929874
Report Number(s):
BNL-80446-2008-JA
Journal ID: ISSN 0009-2509; CESCAC; TRN: US0806665
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Chemical Engineering Science; Journal Volume: 62; Journal Issue: 9
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACTIVATION ENERGY; AUGMENTATION; BEAMS; GELS; KINETICS; POLYMERIZATION; SLURRIES; SOLIDIFICATION; SYNCHROTRON RADIATION; X-RAY DIFFRACTION; national synchrotron light source

Citation Formats

Provis,J., and van Deventer, J.. Geopolymerisation Kinetics. 1. In situ Energy-Dispersive X-ray Diffractometry. United States: N. p., 2007. Web. doi:10.1016/j.ces.2007.01.027.
Provis,J., & van Deventer, J.. Geopolymerisation Kinetics. 1. In situ Energy-Dispersive X-ray Diffractometry. United States. doi:10.1016/j.ces.2007.01.027.
Provis,J., and van Deventer, J.. Mon . "Geopolymerisation Kinetics. 1. In situ Energy-Dispersive X-ray Diffractometry". United States. doi:10.1016/j.ces.2007.01.027.
@article{osti_929874,
title = {Geopolymerisation Kinetics. 1. In situ Energy-Dispersive X-ray Diffractometry},
author = {Provis,J. and van Deventer, J.},
abstractNote = {In situ energy-dispersive X-ray diffractometry, using a polychromatic synchrotron beam and a 'laboratory-sized' sample, is used to provide a direct measurement of the kinetics of geopolymerisation. The effects of sample SiO{sub 2}/Al{sub 2}O{sub 3} ratio, Na/(Na+K) ratio and reaction temperature are investigated. The results obtained support recent propositions that the initial gel phase formed during geopolymerisation is later transformed to a second, probably more-ordered gel phase, and provide detailed information regarding the rate of formation of the first gel phase during the first 3 h of reaction. Increasing the SiO{sub 2}/Al{sub 2}O{sub 3} ratio generally decreases the initial rate of reaction, with the highest SiO{sub 2}/Al{sub 2}O{sub 3} ratio samples showing what appears to be a pause in the reaction corresponding roughly to the solidification of the geopolymeric binder. Mixed (Na,K)-aluminosilicate geopolymers with moderate SiO{sub 2}/Al{sub 2}O{sub 3} ratios behave similarly to pure Na- or K-aluminosilicate compositions of higher SiO{sub 2}/Al{sub 2}O{sub 3} ratio. Fitting a simplified first-order rate expression to the overall reaction process at different temperatures allows the calculation of an effective overall activation energy, which may be useful in comparing geopolymerisation of slurries with different compositions.},
doi = {10.1016/j.ces.2007.01.027},
journal = {Chemical Engineering Science},
number = 9,
volume = 62,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}