engleski

Li-aluminosilicate materials useful for formation of eucryptite ceramics

The last decade’ s zeolites were used as starting materials in the novel method of preparing aluminosilicate-based ceramics. It was shown that zeolites were promising precursors because of their decomposition process after heating and their performing to an amorphous phase which further recrystallized into a dense ceramic phase at relatively low temperatures.The idea of this study is to synthesize aluminosilicate-based ceramics using as starting materials. Lithium-amorphous aluminosilicate gels were prepared by two different procedures: 1. Preparing Na2O-Al2O3-SiO2-H2O amorphous gel by mixing Na2SiO3 solution with NaAlO2 solution and then exchanging the sodium with lithium cation from LiCl solution. The obtained gel is then washed and dried. 2. By mixing together Li-silicate solutions (prepared by the dissolution of fumed silica in LiOH.H2O solution) and Li-aluminate solution (prepared by dissolution of aluminium wire in LiOH.H2O solution) at room temperature, separation of the precipitated amorphous solid phase, washing and drying. The two amorphous gels were heated at specific transition temperatures (determined by differential scanning calorimetry). The starting gels and the obtained ceramic materials are characterized using combined information from differential scanning calorimetry (DSC), thermogravimetry (TG/DTG), X-ray powder diffraction (XRPD), IR spectroscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDXS). A comparison of the mechanism of the process and the obtained phase after heating of the gels with the ceramic materials obtained after thermal treatment of zeolites: LiA(BW) and Li-exchanged zeolite A is studied.

Materials; Li-aluminosilicate; Formation; Eucryptite Ceramics

nije evidentirano