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Which raw materials provide silica and alumina for portland cement?
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Cement
The cement-making process, from crushing and grinding of raw materials, through roasting of the ground and mixed ingredients, to final cooling and storing of the finished product.
In the production of portland cement, silica and alumina are primarily derived from argillaceous (clayey) raw materials.1
Common argillaceous materials used to provide these components include:
Additionally, kaolin is utilized as an argillaceous component specifically for white portland cement. While these materials serve as the primary sources, other substances may be incorporated to achieve specific compositions. For instance, bauxite is used as a source of alumina, and silica sand may be added to increase the silica content. Furthermore, blast-furnace slag is sometimes used as a raw material because it naturally contains lime, silica, and alumina.1