engleski

Kinetic study of LiAlSiO4 formation from Li-exchanged zeolite A by time-resolved sinchrotron powder diffraction

Thermal transformation of |Li|-LTA was followed by in situ, time-resolved synchrotron X-ray powder diffraction. The powder diffraction experiment was carried out in non-isothermal mode, using transmission geometry with capillary sample and an imaging plate detector. The |Li|-LTA was heated linearly, from 30 oC to 1000 oC, using different heating rates. Most amount of the |Li|-LTA was transformed into an amorphous aluminosilicate phase at about 820 oC. At about 790 oC, a new crystalline phase of β -eucryptite was started to crystallize from the amorphous phase. Kinetics of non-isothermal amorphization of |Li|-LTA and crystallization of β -eucryptite are analyzed by the changes of the rate constants during heating. Apparent activation energies of the amorphization of |Li|-LTA and crystallization of β -eucryptite are determined and kinetic equations for the mentioned processes are derived.

Non-isothermal transformation; Li-exchanged zeolite A; Amorphous aluminosilicate; β -eucryptite; Mechanism; Kinetics

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