The correct answer is: b) Limestone.
Limestone is a sedimentary rock composed mainly of calcium carbonate (CaCO3). It is the most common type of rock found in the Earth’s crust and is used in a variety of industries, including cement manufacturing.
Cement is a binding agent that is used to hold together aggregates (such as sand and gravel) to form concrete. It is made by heating limestone and clay to a high temperature, which causes them to react and form a new substance called clinker. The clinker is then ground into a powder and mixed with water to form cement paste.
The limestone used in cement manufacturing is typically high in calcium carbonate. When heated, the calcium carbonate decomposes into calcium oxide and carbon dioxide. The calcium oxide then reacts with the clay to form calcium silicates, which are the main components of cement.
In addition to limestone, other minerals that are commonly used in cement manufacturing include clay, sand, gypsum, and iron ore. The proportions of these minerals vary depending on the type of cement being produced.
Iron ore is not used in cement manufacturing. It is a mineral that is used to produce iron and steel.