MANGANESE IN STEEL

Crude Steel

Crude steel is produced by the refining of pig iron, ferrous scrap and DRI and is an intermediate step in the production of carbon, stainless and alloy steels. Most crude steel is now produced in either basic oxygen furnaces (BOF) or electric arc furnaces (EAFs). Manganese and other ferroalloys are added to crude steel either in the furnace or after the steel has been tapped into ladles. Manganese is added as high-carbon, medium-carbon or low-carbon ferromanganese (HC, MC and LC FeMn) and silico-manganese (SiMn).

As a desulphurising agent, manganese is an essential additive in all steelmaking processes. It is also an alloying addition that imparts strength, toughness, hardness and formability to high-strength and special steels. The addition of manganese has the following advantages:

• it prevents extreme oxidation during refining

• it deoxidises refined steel, enhancing the activity of silicon

• it combines with sulphur to form high melting sulphides, which avoids cracking during hot rolling

• it controls iron carbide precipitation in order to avoid embrittlement

Manganese consumption

Althrough emerging applications such as reachargeable batteries show great prospects as usage growth driver, steelmaking makes up ~97% of manganese consumption. Without manganese, the modern infrastructure we rely on every day, from bridges to skyscrapers would not be possible.