Question

How is cast iron different from pig iron?

Answer 1

Hint: We know that iron has many forms. Based on the percentage of purity and composition of other non-metal elements. Pig iron is somewhat more impure iron compared to cast iron. Cast iron and pig iron are different in some physical properties such as hardness ductility.

Complete step by step answer:
We know that iron has different forms based on the percentage of impurities and composition of impurities. Pig iron and cast iron have major constituents as iron but their preparation, properties, and uses are different. Iron is used in many industries and factories for different purposes. So we need to extract iron from its ore.
Iron is extracted from its oxide ore by the reduction in a blast furnace. In the furnace, Iron is reduced at various stages by different reducing agents. Finally, we obtain molten iron from the blast furnace. This molten iron is allowed to solidify to form pig iron. Pig iron contains around 4% of carbon and other impurities such as Si, P, S, and Mn.
Cast iron contains around 3% of carbon which is slightly less than pig iron. Pig iron is remelted and cast into metal parts to obtain cast iron. Cast iron is very hard and brittle compared to pig iron.

Note: Non-metallic impurities cause iron to be much more brittle. Carbon and iron are combined in different compositions to form a different type of iron. Impurities in pig iron arise due to reduction by coke, some other impurities present in the ore are left after reduction by coke.