ABSTRACT
The cement clinker manufactured by heating raw materials such as limestone, clay, bauxite, and other trace materials together in a rotary cement kiln at high temperature (1400°–1600°C) contains four major compounds: tricalcium silicate (3CaO·SiO2, alite), dicalcium silicate (2CaO·SiO2, belite), tricalcium aluminate (3CaO·Al2O3), and tetracalcium aluminoferrite (4CaO·Al2O3·Fe2O3). Calcium originated from limestone, silicon, and aluminum from clay and iron oxide from bauxite fuse together to produce a clinker consisting of these four major compounds. These four major compounds are expressed in a shorthand notation of cement chemistry as C3S = 3CaO·SiO2, C2S = 2CaO·SiO2, C3A = 3CaO·Al2O3, C4AF = 4CaO·Al2O3·Fe2O3, where C = CaO, S = SiO2, A = Al2O3, F = Fe2O3, Cs = CaSO4, and H = H2O.
