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Molecular mechanisms responsible for the structural changes occurring during geopolymerization: Multiscale simulation
Author(s) -
White Claire E.,
Provis John L.,
Proffen Thomas,
van Deventer Jannie S. J.
Publication year - 2012
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.12743
Subject(s) - metakaolin , aluminosilicate , geopolymer , dissolution , chemical engineering , materials science , silicate , chemistry , composite material , organic chemistry , catalysis , compressive strength , engineering
To date, the fundamental details of the molecular structural changes and associated mechanisms, which take place during the formation of aluminosilicate geopolymer gels, have remained largely elusive. Here, density functional theory‐based coarse‐grained Monte Carlo modeling, a multiscale simulation technique, is used to simulate the geopolymerization reaction and to determine the molecular mechanisms controlling this process. Silica supplied by the alkaline solution plays a significant role in enhancing the dissolution of the solid aluminosilicate precursor (metakaolin, in this case) and the polymerization of the gel. In the reaction between NaOH and metakaolin, in the absence of initially dissolved silica, the solid precursor completely dissolves and the aluminosilicate gel forms via the percolation of small aluminosilicate clusters. On the other hand, in the presence of dissolved silicate, the metakaolin only partially dissolves, as the aluminosilicate gel precipitates on the surfaces of the metakaolin particle after a period of time. © 2011 American Institute of Chemical Engineers AIChE J, 2012