11 Oxygen Furnace
In this process, the amount of carbon is decreased by regulating the amount of oxygen that is injected into the pig iron. The oxygen removes the unwanted carbon by oxidation. This unwanted carbon, together with a mixture of other impurities constitutes the slag and is removed from the furnace.
The first way to reduce the carbon is the basic oxygen furnace steel making process.
Basic oxygen steelmaking (BOS, BOP, BOF, or OSM), also known as Linz-Donawitz steelmaking or the oxygen converter process is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into low-carbon steel. The process is known as basic because fluxes of burnt lime or dolomite, which are chemical bases, are added to promote the removal of impurities and protect the lining of the converter.
The process was invented in 1948 by Swiss engineer Robert Durrer and commercialized in 1952–1953 by the Austrian steelmaking company VOEST and ÖAMG. The LD converter, named after the Austrian towns Linz and Donawitz, is a refined version of the Bessemer converter where blowing of air is replaced with blowing oxygen. It reduced capital cost of the plants and smelting time, and increased labor productivity. Between 1920 and 2000, labor requirements in the industry decreased by a factor of 1,000, from more than three man-hours per metric ton to just 0.003. The majority of steel manufactured in the world is produced using the basic oxygen furnace. In 2000, it accounted for 60% of global steel output.
Modern furnaces will take a charge of iron of up to 400 tons and convert it into steel in less than 40 minutes.
Video Explanation
Watch this 7:44 video BOF Steel Making 3d animation produced by Santaam Banerjee (2020).
Derived from Basic oxygen steelmaking – Wikipedia available and accessed 6 February 2024 and The Virtual Machine Shop at http://jjjtrain.com/3engineering/5eng_metallurgy/eng_metallurgy_11.html retrieved from the WayBack Machine internet archive 16 January 2024.