ISSN:
1572-8943
Keywords:
differential scanning calorimetry
;
FTIR
;
inorganic polymer glasses
;
kaolinite
;
metakaolinite
;
TG
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The degree of dehydroxylation of kaolinite, DTG and DIR, respectively, is characterized by thermogravimetric analysis (TG) and Fourier transform infrared spectroscopy (FTIR). The relation between DTG and DIR based on the infrared absorptions at 3600–3700, 915, 810, and 540 cm−1 is established. Three regions can clearly be distinguished: the dehydroxylation region (DTG〈0.9), the metakaolinite region (0.9〈DTG〈1) and the ‘spinel’ region(DTG=1). The effect of the degree of dehydroxylation of kaolinite on the amount of reactive material is measured by the reaction enthalpy, ΔH, of the low-temperature reaction of the dehydroxylated kaolinite with a potassium silicate solution using differential scanning calorimetry (DSC). |ΔH| increases almost linearly with DTG in the dehydroxylation region. In the metakaolinite region, ΔH and thus the amount of reactive material, becomes constant. |ΔH| is sharply decreasing when metakaolinite transforms into other phases in the ‘spinel’ region. No significant differences in the reactivity of the dehydroxylates is detected with DSC. According to FTIR, the use of partially dehydroxylated kaolinite is not influencing the molecular structure of the low-temperature synthesized aluminosilicates, but residual kaolinite is retrieved as an additive.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1010138130395
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