Difference Between Sponge Iron and Pig Iron
Sponge and Pig iron are different from each other in terms of their use and the way they are produced. Although both are forms of iron but they have different properties.
Pig iron is produced by melting iron ore under high pressure with charcoal and limestone. This has high carbon content and is brittle and unstable. To put it to commercial use this pig iron obtained by melting iron ore is melted and blended to form wrought iron, steel and cast iron. These forms of pig iron are then put to commercial use.
Pig iron was discovered in 11th century by Chinese smiths. Wrought iron is used in making furniture, grills etc and this is why its demand has increased over last couple of years. Wrought iron is also produced from sponge iron.
When iron ore is subjected to reduction process, it produces sponge iron which is also known as reduced iron. Gas emitted from coal and natural gas are two most common reducing agents which are used in this process although many more methods of reducing iron have been developed which do not need reducing agents and melting the ore. Reduction can be done in Charcoal ovens, oxygen furnace and blast furnace.
Sponge iron is used in electric furnaces because it has high iron content and is a superior form of iron. It can also be mixed with different metals and put to different types of uses related to iron.