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The influence of water steam on the direct phase transformation of zeolite NaA to nepheline by thermal treatment
Author(s) -
Lutz W.,
Engelhardt G.,
FichtnerSchmittler H.,
Peuker Ch.,
Löffler E.,
Siegel H.
Publication year - 1985
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170200917
Subject(s) - nepheline , zeolite , phase (matter) , amorphous solid , atmospheric temperature range , materials science , chemical engineering , thermal , mineralogy , chemistry , crystallography , thermodynamics , organic chemistry , catalysis , physics , engineering
Heating of zeolite NaA leads to the consecutive formation of amorphous phase, carnegieite and nepheline in the high temperature region. These phase transformations are influenced not only by temperature but also by the presence of water (inside of the crystals). Water causes destruction of zeolite framework by hydrolytic splitting of Si‐O‐Al‐bonds in addition to thermal effects. Thus, the amorphous phase as the first product of phase transformation occurs in the presence of water steam at a lower temperature. The formation of the crystalline phases carnegieite and nepheline was observed in a temperature range, 300 K lower than usually, and without occurrence of the amorphous phase.