- published: 11 Jul 2015
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A steel mill or steelworks is an industrial plant for the manufacture of steel.
Steel is an alloy of iron and carbon. It is produced in a two-stage process. First, iron ore is reduced or smelted with coke and limestone in a blast furnace, producing molten iron which is either cast into pig iron or carried to the next stage as molten iron. In the second stage, known as steelmaking, impurities such as sulfur, phosphorus, and excess carbon are removed and alloying elements such as manganese, nickel, chromium and vanadium are added to produce the exact steel required. In the late 19th Century and early 20th Century the world's largest steel mill was located in Barrow-in-Furness, UK. Today, the world's largest steel mill is in Gwangyang, South Korea.
Steel mills turn molten steel into blooms, ingots, slabs and sheet through casting, hot rolling and cold rolling.
An integrated steel mill has all the functions for primary steel production:
The principal raw materials for an integrated mill are iron ore, limestone, and coal (or coke). These materials are charged in batches into a blast furnace where the iron compounds in the ore give up excess oxygen and become liquid iron. At intervals of a few hours, the accumulated liquid iron is tapped from the blast furnace and either cast into pig iron or directed to other vessels for further steelmaking operations. Historically the Bessemer process was a major advancement in the production of economical steel, but it has now been entirely replaced by other processes such as the basic oxygen furnace.