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Argonoxygen decarburization (AOD) is a process primarily used in stainless steel making and other high grade alloys with oxidizable elements such as chromium and aluminium. After initial melting the metal is then transferred to an AOD vessel where it will be subjected to three steps of refining; decarburization, reduction, and desulfurization.
Desulfurization or desulphurisation is a chemical process for the removal of sulfur from a material. [1] The term usually refers to the removal of sulfur from a molecule or a material by hydrogenolysis: [2] R 2 S + 2 H 2 → 2RH + H 2 S. Hydrogen is the ultimate sulfur acceptor. As applied to oil refinery streams, the conversion is known as ...
In making crucible steel, the blister steel bars were broken into pieces and melted in small crucibles, each containing 20 kg or so. This produced higher quality metal, but increased the cost. The Bessemer process reduced the time needed to make lower-grade steel to about half an hour while requiring only enough coke needed to melt the pig iron.
Direct reduction processes can be divided roughly into two categories: gas-based and coal-based. In both cases, the objective of the process is to remove the oxygen contained in various forms of iron ore (sized ore, concentrates, pellets, mill scale, furnace dust, etc.) in order to convert the ore to metallic iron, without melting it (below 1,200 °C (2,190 °F)).
The primary advantage of the early blast furnace was in large scale production and making iron implements more readily available to peasants. [26] Cast iron is more brittle than wrought iron or steel, which required additional fining and then cementation or co-fusion to produce, but for menial activities such as farming it sufficed.
Electrical steel is one material that uses decarburization in its production. To prevent the atmospheric gases from reacting with the metal itself, electrical steel is annealed in an atmosphere of nitrogen, hydrogen, and water vapor, where oxidation of the iron is specifically prevented by the proportions of hydrogen and water vapor so that the only reacting substance is carbon being oxidized ...
Today, it plays an essential role in the blending of different ores and, above all, in the incorporation of mineral wastes of varying iron content. This recycling role improves profitability and limits the amount of waste generated by steel complexes, which generate numerous iron-rich residues (slag, sludge, dust, etc.). [2]
The first oxygen converters in the US were launched at the end of 1954 by McLouth Steel in Trenton, Michigan, which accounted for less than 1% of the national steel market. [3] U.S. Steel and Bethlehem Steel introduced the oxygen process in 1964. [3] By 1970, half of the world's and 80% of Japan's steel output was produced in oxygen converters. [3]