Naslov
Study of structural transformations in potassium- exchanged zeolite A induced by thermal and mechanochemical treatments

Autori
Kosanović, Cleo ; Subotić, Boris ; Šmit, Ivan ; Čižmek, Anja ; Stubičar, Mirko ; Tonejc, Antun

Izvornik
Journal of materials science (0022-2461) 32 (1997); 73-78

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
structural transformations ; potassium-exchanged zeolite A ; amorphization by thermal or mechanochemical treatments ; crystallization processes ; differential thermal analysis (DTA) ; X-ray diffraction (XRD) ; Fourier transform infrared (FTIR) spectroscopy.

Sažetak
Thermal transformations of potassium-exchanged zeolite A and the X-ray amorphous material obtained by ball milling the potassium-exchaged zeolite A were investigated by different methods, such as differential thermogravimetric analysis (DTA), differential scanning calorimetry (DSC), X- ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Controlled heating of crystalline, potassium-exchanged zeolite A causes a phase transformation in the sequence: [0.22Na2O, 0.78K2O]x(Al2O3)x(2SiO2)x(3.48H2O)--- amorphous phase---crystalline (kalsilite+kaliophilite) phases, while the heating of mechanochemically amorphous potassium-exchanged zeolite A results in its transformation into a mixture of kalsilite and kaliophilite. The differences in the pathways of the transformation processes are discussed in terms of the structural properties of the starting materials.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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