“I am used as a reducing agent in preparing other metals such as thorium and uranium. It is also used as an alloying agent for aluminium, beryllium, copper, lead and magnesium alloys.

I am widely used. There are vast deposits of limestone (calcium carbonate) used directly as a building stone and indirectly for cement. When limestone is heated in kilns it gives off carbon dioxide gas leaving behind quicklime (calcium oxide).