The Basic Oxygen Furnace (BOF), or Bessemer Converter, is the dominant technology for mass-producing steel globally.

The BOF process involves blowing pure oxygen at hgh speed onto a bath of molten pig iron—derived from the blast furnace—and scrap steel. This high-velocity oxygen rapidly oxidizes and removes impurities like carbon, silicon, and phosphorus, refining the iron into high-quality steel in a cycle that often takes less than an hour. The use of basic fluxes is critical to form the BOF slag that absorbs these impurities, making this process central to modern, efficient steel production.