Synthesis of lithium aluminosilacate glass and glass-ceramics from spodumene material

The synthesis of lithium aluminosilicate glasses and glass-ceramics from spodumene material was investigated. Basing on the general formula Li2−2(x+y)MgxZnyAl2−mBmSizO2z+4, 40 mol% of the Li2O was replaced with 20 mol% of MgO and 20 mol% of ZnO, and 40 mol% of Al2O3 with B2O3. BaO was also introduced for improving glass melting behaviour. 2 and 5 wt.% TiO2 was used as nucleation agent. In the TiO2-containing glasses, virgilite was primarily crystallized. The degree of crystallinity was considerably improved at 900 °C. Virgilite was transformed into crystals of spodumene solid solutions embedded in a glass matrix, while Zn-gahnite formed a second crystalline phase. Rutile was crystallized in the glasses containing 5 wt.% TiO2. The thermal expansion coefficient for the 2% and the 5 wt.% TiO2-containing glass-ceramics was 6.39×10−7 and 17.1×10−7 K−1, respectively (70–300 °C).