The limestone in the charge of a blast furnace decomposes to give lime and carbon dioxide. The lime thus obtained

controls the grade of pig iron

acts as iron-bearing mineral

supplies heat to reduce ore and melt the iron

forms a slag by combining with impurities

is used as a ballast for rail road

is mixed with tar for road making

consists of calcium, aluminum and ferrous silicates

all of the above

pig iron

cast iron

Wrought iron

steel

soft and gives a coarse grained crystalline structure

soft and gives a fine grained crystalline structure

hard and gives a coarse grained crystalline structure

hard and gives a fine grained crystalline structure

soft and gives a coarse grained crystalline structure

soft and gives a fine grained crystalline structure

hard and gives a coarse grained crystalline structure

hard and gives a fine grained crystalline structure