2050 – 04 – Working with a Basic Oxygen Furnace

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Pig iron isn’t entirely pure. It needs to be further refined in order to create steel. The two processes used to create steel use the electric arc furnace (EAF) and the basic oxygen furnace (BOF).

Seventy percent of the steel created in the US is made with a basic oxygen furnace. In this process, molten pig iron is added to the basic oxygen furnace with steel scrap among other metals. The basic oxygen furnace pumps in oxygen from under the furnace. This added gas latches on to impurities, leaving steel behind as it flows out of the furnace. Like the blast furnace, the basic oxygen furnace creates carbon monoxide.

Most impurities combine with oxygen and leave the furnace, but others bond with the lime and become slag on the bottom of the furnace.