ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7

Published monthly
 

Study of the thermal stability of the natural zeolite heulandite

F. Pechar and D. Rykl

Institute of Geology and Geotechnics, Czechoslovak Academy of Sciences, CS-182 09 Prague

 

Abstract: On the basis of the course of the DTA and TGA curves the natural zeolite heulandite (Poonah locality, India) was subjected to the isothermal decomposi­ tion at the various temperatures (0/°C: 20, 200, 280, 470, 510, 620, 660, 760, 820, and 1000). The decomposition products were studied by means of the X-ray powder methods and by the infrared absorption spectroscopy. It was found that the heulandite structure is stable up to the temperature of 280 °C. At the temperature exceeding 280 °C the transformation into the modification of heulandite В occurs. From the temperature of 47.0 °C upwards the amor­ phous phase begins to be formed, from which at the temperature exceeding 500 °C a mixture of minerals wairakite 4- a-Si0 2 and/or anorthite + Si0 2 starts to appear. In the course of dehydration starting from 200 °C, in the cavities of heulandite simultaneously proceeds the heterolytic reaction, at which the free proton is formed, which immediately attacks the bridge oxygens in the bridge ( ) — Al—О—Si under the formation of hydroxyl groups. These groups partly remain in the complicated complex up to the high temperatures.

Full paper in Portable Document Format: 393a369.pdf

 

Chemical Papers 39 (3) 369–377 (1985)

Friday, July 19, 2019

IMPACT FACTOR 2018
1.246
SCImago Journal Rank 2018
0.274
SEARCH
Advanced
VOLUMES
International Conference on Coordination and Bioinorganic Chemistry
46th International Conference of SSCHE
© 2019 Chemical Papers