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Synthesis of γ - and β - eucryptite obtained by thermal transformation of LiA(BW), Li-exchanged zeolite A and of Li-exchanged amorphous aluminosilicate gel.

Zeolites are promising precursors to aluminosilicate-based ceramics because they are readily synthesized with a narrow particle size distribution and can be obtained at low cost. Thermal transformations of Li-exchanged amorphous aluminosilicate gel, LiA(BW) and Li-exchanged zeolite A.have been studied using combined information from differential scanning calorimetry (DSC), differential thermal gravimetry (DTG), X-ray powder difractometry, FTIR-spectroscopy, scanning electron microscopy (SEM) and energy depressive X-ray spectroscopy (EDXS). Each starting material is following different path way of the process. Zeolite LiA(BW) is tansformed to &#947; - -eucryptite at lower temperatures (<800oC) and then to &#946; - eucryptite after heating at higher temperatures (>800oC) Li-exchanged zeolite A is first transformed to an amorphous phase and then to &#946; - eucryptite at temperatures higher than 1000oC. Direct transformation from the Li-gel is forming &#946; - eucryptite depending on the ratio of the succefully exchanged cation and the molar ratio SiO2/Al2O3 in the gel.

Synthesis; Eucryptite; LiA(BW); Thermal transformation of; Li-exchanged zeolite A; Li-exchanged amorphous aluminosilicate gel

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