PSM V38 D165 Vertical section of a 17th and 18th century blast furnace

Cold blast, in ironmaking, refers to a

metallurgical furnace A metallurgical furnace, more commonly referred to as a furnace, is a device used to heat and melt metal ore to remove gangue, primarily in Metal, iron and steel production. The heat energy to fuel a furnace may be supplied directly by fuel comb ...

where air is not preheated before being blown into the furnace. This represents the earliest stage in the development of ironmaking. Until the 1820s, the use of cold air was thought to be preferable to hot air for the production of high-quality iron; this effect was due to the reduced moisture in cool winter air. The discovery by

James Beaumont Neilson James Beaumont Neilson (22 June 1792 – 18 January 1865) was a Scottish inventor whose hot-blast process greatly increased the efficiency of smelting iron. Life He was the son of the engineer Walter Neilson, a millwright and later engin ...

in about 1825 of the beneficial effects of the

hot blast Hot blast refers to the preheating of air blown into a blast furnace or other metallurgical process. As this considerably reduced the fuel consumed, hot blast was one of the most important technologies developed during the Industrial Revolution. ...

led to the rapid obsolescence of cold blast ironworks in

Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...

, where hot blast was in general use by 1835. Cold blast ironworks survived longer in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, but the use of hot blast as a method of smelting iron with

anthracite Anthracite, also known as hard coal, and black coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the hig ...

was introduced in 1836, and the increasing US production of coke gradually drove out the cold blast furnaces. However, one of the last known operating cold blast

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...

furnaces, Pleasant (formerly Eagle) Furnace, in Curtin, Pennsylvania did not close until 1921.

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Bibliography

* {{Iron and steel production Blast furnaces Steelmaking