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Chemical Processes During Energy‐Saving Preparation of Lightweight Ceramics
Author(s) -
Kazantseva Lidia K.,
Rashchenko Sergey V.
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12980
Subject(s) - alkali metal , scanning electron microscope , ceramic , materials science , chemical engineering , mineralogy , dehydration , sodium , chemistry , composite material , metallurgy , organic chemistry , biochemistry , engineering
Lightweight glass‐ceramic material similar to foam glass was obtained at 700°C–800°C directly from alkali‐activated silica clay and zeolitized tuff without preliminary glass preparation. It was characterized by low bulk density of 100–250 kg/m 3 and high pore size homogeneity. Chemical processes occurring in alkali‐activated silica clay and zeolitized tuff were studied using X‐ray diffraction, thermal gravimetry, IR‐spectroscopy, and scanning electron microscopy. Pore formation in both compositions is caused by dehydration of hydrated sodium polysilicates ( Na 2 O · m SiO 2 · n H 2 O ), formed during alkali activation. Additional pore‐forming gas source in alkali‐activated zeolitized tuff is trona, Na 3 ( CO 3 )( HCO 3 )·2 H 2 O , formed during interaction between unbound NaOH and CO 2 and H 2 O from air. Influence of mechanical activation of raw materials on chemical processes occurring in alkaline compositions was also studied.