- Calcium aluminate refers to a group of compounds formed primarily from calcium oxide (CaO) and aluminum oxide (Al₂O₃), with the general chemical formula varying based on the specific phase—such as CaAl₂O₄, CaAl₄O₇, or Ca₃Al₂O₆.
- These compounds are typically synthesized by heating a mixture of lime and alumina at high temperatures in a kiln. The resulting materials are highly refractory, meaning they can withstand extremely high temperatures without decomposing, making calcium aluminate essential in various high-performance construction and industrial applications.
- One of the most significant applications of calcium aluminate is in the production of calcium aluminate cements (CACs), also known as high-alumina cements. These specialized binders are known for their rapid strength development, resistance to chemical corrosion, and high thermal stability. CACs are used in environments where conventional Portland cement would fail, such as in wastewater treatment plants, chemical processing facilities, and high-temperature installations. Their resistance to sulfate attack, low permeability, and tolerance to aggressive substances make them ideal for constructing sewer linings, refractory castables, and repair mortars.
- In the refractory industry, calcium aluminate is a critical component of monolithic refractories used to line furnaces, kilns, and incinerators. Its high melting point and ability to maintain structural integrity at elevated temperatures provide crucial support in steelmaking, ceramics, and glass manufacturing. Calcium aluminate-based refractories also offer excellent resistance to slag and metal penetration, which enhances their longevity and efficiency in high-wear environments.
- From a chemical standpoint, calcium aluminates exhibit hydraulic properties—they react with water to form stable hydrates, which contribute to their strength and durability. However, unlike Portland cement, the hydration of calcium aluminate cements leads to the formation of different mineral phases (such as CAH₁₀, C₂AH₈, and C₃AH₆), which are responsible for their unique setting behavior and performance characteristics. These hydrates give CACs early strength gain and allow for construction in low-temperature or chemically aggressive conditions.
