Depending on density, lightweight ceramic can be used in several applications such as construction, cutting tools, amour system, wear lining refractories, and wastewater treatment. The growth of lightweight ceramics in such applications becomes a motivation in developing the materials using geopolymer technology. With the uniqueness of geopolymer composition and the help of geopolymerization, high-temperature routes are no longer required to produce ceramic materials. The geopolymer, so called inorganic polymer will convert the amorphous and semi-crystalline phase into a crystalline phase during sintering. The synthesis at low temperatures is energy efficient and more environmentally friendly than older materials. The formation of geopolymer is a polymerization process similar to the polycondensation of an organic polymer. Therefore, the overall process is termed as geopolymerization. The geopolymerization can transfer Al and Si containing wastes into geopolymers with high mechanical strength and highly durable construction materials. The use of kaolin and fly ash as source materials in the formation of geopolymer ceramics could achieve good economic and environmental benefits. This chapter highlights the role of geopolymer systems in the production of ceramic materials for lightweight applications. It covers basic knowledge on ceramics, the formation of geopolymer, fabrication of light-weight ceramic materials using the geopolymer method, and the characterization and properties of the products.
