General Knowledge - General Science - Discussion

Limestone is calcium carbonate and gypsum is also used in making cement.

Both are very useful in manufacturing the cement.

Gypsum is also used in cement manufacturing but why the answer is option c?

The most common raw meterial used in cement production are;

* Limestone (supplies the bulk of the lime).
* Clay, marl or shale (supplies the bulk of the silica, alumina and ferric oxide).
* Other supplementary materials such as sand, fly ash/pulverised fuel ash (PFA), or ironstone to achieve the desired bulk composition.

During the cement manufacturing process, upon the cooling of clinker, a small amount of gypsum is introduced during the final grinding process. Gypsum is added to control the "setting of cement". Gypsum is a mineral and is hydrated calcium sulfate in chemical form.

Good, Thanks.