Traditional Culture Encyclopedia - Traditional stories - Why blast furnace ironmaking can only make pig iron but not pure iron?

Why blast furnace ironmaking can only make pig iron but not pure iron?

The main function of blast furnace is to reduce iron in iron ore. Compared with pure iron, it contains more silicon, phosphorus, carbon and sulfur. It is difficult to reduce the content of these elements to a certain extent by blast furnace. However, the content of these elements in pure iron is extremely low, and these elements must be removed by refining outside the furnace, such as RH refining.