Composition of cement - Penn State College of Engineering
2000year3month17day · Portland cement is manufactured by crushing, milling and proportioning the following materials: Lime or calcium oxide, CaO: from limestone, chalk, shells, shale or calcareous rock. Silica, SiO 2: from sand, old bottles, clay or argillaceous rock. Alumina, Al 2 O 3: from bauxite, recycled aluminum, clay. Iron, Fe 2 O 3: from from clay, iron ore ...