Reactions in Eucryptite-Based Lithium Aluminum Silicates
The reaction sequence to synthesize -eucryptite, LiAlSiO4, from the raw ingredients SiO2, Li2CO3, and Al2O3 was studied using thermal analysis and X-ray diffraction techniques. Reactions were examined by heating the raw ingredients as two-component and three-component mixtures in air, then cooling for phase analysis. In some cases, cyclic heating was performed to ensure a complete reaction. It was found that a complex sequence of reactions involving several intermediate phases occurs. The single oxides (SiO2 and Al2O3) react with Li2CO3 to form the binary oxides (Li2Si2O5, Li2SiO3, and LiAlO2); SiO2 reacts with Li2CO3 before Al2O3. Subsequently, the binary oxides form ternary oxides (LiAlSi2O6 and LiAlSiO4). Finally, the ternary oxides form the equilibrium product, -eucryptite (LiAlSiO4). These reactions are discussed in the context of the thermodynamic properties of the various compounds.
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Document Type: Research Article
Affiliations: Colorado Center for Advanced Ceramics, Metallurgical and Materials Engineering Department, Colorado School of Mines, Golden, Colorado 80401
Publication date: 2010-06-01