Basic Oxygen Steelmaking (LD)
Blowing pure oxygen onto liquid iron (first run at VÖEST in Linz on 27 November 1952) makes steel in under 40 minutes instead of 10-12 hours; with the blast furnace it still makes about 70% of the world's steel.
Open in the interactive tree →Swiss engineer Robert Durrer developed oxygen blowing, and engineers at Austria's VÖEST made it work at scale: a 30-tonne converter in Linz tapped its first steel on 27 November 1952, and a second plant at Donawitz followed in May 1953 (hence LD). A water-cooled lance blows oxygen at the melt, burning out carbon and lifting it to about 1,700 °C; scrap can make up 25-30% of the charge. By 1970 half of the world's steel came from oxygen converters, and in 2024 the blast-furnace route that feeds them made 70.4% of the 1.885 billion tonnes of steel, electric arc furnaces 29.1%. Green-steel plants aim to replace the blast furnace in front of the converter.
Prerequisites
- Blast Furnace & Cast Iron~1400Converters are charged with liquid pig iron from the blast furnace.
- Mechanical Refrigeration1834Tonnage oxygen comes from cryogenic air separation, a refrigeration technology
- Bessemer Steel1856It keeps Bessemer's idea of blowing liquid iron but uses pure oxygen instead of air