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Synthesis and characterization of leucite nano-crystalline extracted from Saudi clay for dental application

A.El-Maghraby, K.F.Khaled, Hanan H. Beherei, Amany A. El-Kheshen

Spherical leucite crystals having nanosize were prepared by heating a powdermixture ofmetakaolin, K2SiO4 andNaOH. The geopolymer thus obtained were fired at elevated temperature up to 1100 0Candwere examined byXRD, DTAand XRF techniques. K-based geopolymer (K2O.Al2O3. 4SiO2. 11H2O) was investigated due to its attractive refractory properties and its ability to convert to leucite (KAlSi2O6) on heating. The results show that metakaolin, K2SiO3 solution and KOH to regulate the PHform geopolymer, which may crystallize into cristoballite and lecuite, respectively, under thermal treatment. The geopolymer synthesized at alkaline PH, in turn, remains stable at temperatures until 1100 oC.Afurther increase in temperature to 1100 oCled to the formation of leucite crystals of two different diameters, approximately 40 µm and 10–50 µm. The thermal behavior of K-geopolymer was characterized using a variety of techniques in order to explore the details of dehydration, sintering, and crystallization. K-geopolymer was found to offer many of the benefits such as lower sintering temperatures and compositional control without high costs.