Bessemer furnaces

Duplex (1) An integrated steelmaking process in which iron is converted to steel in a Bessemer furnace with a basic lining, and the molten product is transferred to a basic lined arc furnace in which the remaining impurities are oxidized. Developed in Germany and widely used there and elsewhere around 1900. 

The next major improvement was the development of the Siemens or open hearth furnace. Unlike the Bessemer furnace, which relied solely upon the oxidation of various elements in the bath for heat, the open hearth furnace was fired by burners, which allowed for external fuel to add considerable melting power to the process. The most important aspect of the open hearth process was its use of preheated air. Without air preheating, the metal would have melted very slowly, if at all. The air preheating occurred in refractory brick checkers (or checker-work) located under... 

The various steelmaking processes were all eventually supplanted (3,4). The first of the newer techniques was the historic pneumatic or Bessemer process, introduced in 1856. Shortiy thereafter, the regenerative-type furnace, known in the 1900s as the open-hearth furnace, was developed in the United... 

Top-Blown Basic Oxygen Process. The top-blown basic oxygen process is conducted ia a cylindrical furnace somewhat similar to a Bessemer converter. This furnace has a dished bottom without holes and a tmncated cone-shaped top section ia which the mouth of the vessel is located. The furnace shell is made of steel plates ca 50-mm thick it is lined with refractory 600—1200-mm thick (11). 

In modem steel (qv) manufacture, pebble quicklime is used as a flux in the basic oxygen, basic open-hearth, basic Bessemer, and basic electric furnaces. 

Bessemer Open hearth Electric Basic oxygen furnace Total... 

The impure iron is made into steel by burning out most of the carbon, sulfur, and phosphorus. Today there are three common furnace types for making steel—the open-hearth furnace (85% of U.S. production), the electric arc furnace (10%), and the Bessemer converter (5%). These furnaces differ in construction but the chemistry is basically similar. 

Beryllium difiuoride, dipole in, 293 Berzelius, Jons, 30 Bessemer converter, 404 Beta decay, 417 Bela particle, 417 Bicarbonate ion, 184 Bidentaie. 395 Billiard ball analogy, 6, 18 and kinetic energy, 114 Billiard ball collision, conservation of energy in, 114 Binding energy, 121, 418 Biochemistry, 421 Bismuth, oxidation numbers, 414 Blast furnace, 404 Bohr, Niels, 259 Boiling point, 67 elevation, 325 normal, 68... 

Acid Bessemer An alternative name for the original Bessemer steelmaking process in which the furnace is lined with a silica refractory. It is suitable only for ores relatively free from phosphorus. 

L-D [Linz, Austria and either Dusenverfahren (nozzle process), or Donawitz, the other Austrian town where it was developed] A basic steelmaking process in which oxygen is used instead of air to remove most of the carbon from the molten pig iron. Developed in Austria by the Vereinigte Osterreichisch Eisen und Stahlwerke of Linz, and Osterreichisch Alpine of Donawitz, in the 1930s and 40s commercialized in 1952, and now widely adopted. The furnace is essentially a Bessemer converter, modified with a water-cooled oxygen injector. See also Bessemer. 

Talbot A semi-continuous steelmaking process which combines the Bessemer and Open Hearth processes. Molten pig iron from a Bessemer converter is poured into an Open Hearth furnace containing fresh ore and lime. Impurities in the pig iron oxidize and enter the slag. The process improves the yield of steel and the throughput of the plant. Introduced by B. Talbot at Pencoed, PA, in 1900 and subsequently adopted in Europe. 

A = a basic open-hearth alloy steel B = an acid-Bessemer carbon steel C = a basic open-hearth carbon steel D = an acid open-hearth carbon steel E = an electric furnace steel... 

Carbon unites with molten iron, forming a carbide hence the product of the blast-furnace is not pure iron, but a mixture of iron with its carbide, and also with its sulphide and phosphide, if the ore has contained sulphates or phosphates. When such impure iron is brought in contact with oxygen in a molten or semi-molten condition, the carbon, sulphur, and phosphorus are oxidised mostly before the iron. If lime be present, sulphate and phosphate of calcium are formed. The modern process of removing these impurities is to pour the molten metal into a pear-shaped iron vessel lined with bricks made of magnesia while it is molten, air is blown through the metal, and the carbon burns to carbon dioxide the sulphur and phosphorus are likewise oxidised and combine with lime, a layer of which floats on the surface of the molten metal When these impurities have thus been removed in the Bessemer... 

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