Which of the following is the formula of the iron ore haematite?

$(a)$ What type of ores are calcined? Illustrate by giving a suitable example.
$(b)$ In what form is the calcined ore obtained,and how can it be reduced? Give chemical equations of the reduction process involved for the example provided by you.
$(c)$ Name two metals used as reducing agents by displacing metals of lower reactivity from their compounds.

During the extraction of iron from hematite in a blast furnace,which substance is obtained as slag?

During the electrolytic refining of zinc,it gets :

State whether the following statement is true or false:
The elements or compounds,which occur naturally in the earth's crust,are known as minerals.

Which ore is concentrated by the froth flotation process?