Τίτλος:
Influence of thermal treatment on the water release and the glassy structure of perlite
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
The effect of slow and rapid thermal treatment on water release and the structure of perlite was investigated by employing complementary techniques including X-ray diffraction, infrared spectroscopy and scanning electron microscopy. The study of several perlite samples, with different grain size and origin, has shown that rapid heating has a more pronounced effect on the glassy structure and that this is the only process capable of leading to perlite grain expansion. This process was simulated in a laboratory furnace allowing the careful control of temperature and time of treatment, and, thus, the description of their influence on the expansion process. The results show that molecular water released between 250 and 550 °C affects mostly the expansion process. Infrared spectroscopy provides evidence for additional water release, through dehydroxylation of Si-OH bonds, that may contribute also to expansion with a simultaneous development of the silicate network. The grain morphology was found to correlate with the expansion ratio. The presence of crystallites in raw perlite was shown to affect also the expansion process.
Συγγραφείς:
Roulia, M.
Chassapis, K.
Kapoutsis, J.A.
Kamitsos, E.I.
Savvidis, T.
Περιοδικό:
Journal of Materials Science
Λέξεις-κλειδιά:
Glass; Grain size and shape; Heat treatment; Infrared spectroscopy; Laboratory furnaces; Scanning electron microscopy; Thermal effects; X ray diffraction, Glassy structure; Molecular water; Perlite grain expansion; Perlite samples, Silica
DOI:
10.1007/s10853-006-0325-z
