the fuel used in a blast furnace is

supplies heat to reduce ore and melt the iron

forms a slag by combining with impurities

all of the above

The slag from the blast furnace
* is used as a ballast for rail road
* is mixed with tar for road making
* consists of calcium, aluminum and ferrous silicates

cast iron

Cupola Furnace is a melting device which used to melt cast iron, Bronze and other alloying elements are melted. It is mainly used to convert pig iron to cast iron.

Cupola furnace is employed for melting scrap metal or pig iron for production of various cast irons. It is also used for production of nodular and malleable cast iron.