Bessemer process

related topics
{acid, form, water}
{@card@, make, design}
{company, market, business}
{day, year, event}
{ship, engine, design}

The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly.[1][2] The process had also been used outside of Europe for hundreds of years, but not on an industrial scale.[3] The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron. The oxidation also raises the temperature of the iron mass and keeps it molten.

The process using a basic refractory lining is known as the basic Bessemer process or Gilchrist-Thomas process after the discoverer Sidney Gilchrist Thomas.

Contents

Details

Bessemer converter

The process is carried out in a large ovoid steel container lined with clay or dolomite called the Bessemer converter. The capacity of a converter was from 8 to 30 tons of molten iron with a usual charge being around 15 tons. At the top of the converter is an opening, usually tilted to the side relative to the body of the vessel, through which the iron is introduced and the finished product removed. The bottom is perforated with a number of channels called tuyères through which air is forced into the converter. The converter is pivoted on trunnions so that it can be rotated to receive the charge, turned upright during conversion, and then rotated again for pouring out the molten steel at the end.

Oxidation

The oxidation process removes impurities such as silicon, manganese, and carbon as oxides. These oxides either escape as gas or form a solid slag. The refractory lining of the converter also plays a role in the conversion—the clay lining is used in the acid Bessemer, in which there is low phosphorus in the raw material. Dolomite is used when the phosphorus content is high in the basic Bessemer (limestone or magnesite linings are also sometimes used instead of dolomite)—this is also known as a Gilchrist-Thomas converter, named after its inventor, Sidney Gilchrist Thomas. In order to give the steel the desired properties, other substances could be added to the molten steel when conversion was complete, such as spiegeleisen (an iron-carbon-manganese alloy).

Full article ▸

related documents
Stainless steel
Agate
Polytetrafluoroethylene
Gas mask
Rotaxane
Wafer (electronics)
Microtubule
Pyrite
Amber
Rutile
Hygroscopy
Diffusion
Pipette
Diamondoid
Protactinium
Samarium
Compounds of carbon
Ductility
Perchloric acid
Heavy metal (chemistry)
Intron
Vapor
Polyatomic ion
Active transport
Flagellum
G protein
Vacuum flask
Standard enthalpy change of formation
Acetaldehyde
Rubidium