Birmingham in Jefferson County, Alabama — The American South (East South Central)
The Blast Furnace
Sloss Furnaces National Historic Landmark
In the blast furnace the combination of iron ore, flux (limestone and/or dolomite), coke, and hot air produced molten iron and two waste products: molten slag and blast furnace gas. The molten products collected in the bottom of the furnace and were drained off periodically. The gas left the furnace through the top and was routed to the stoves and boilers where it was used as fuel.
This furnace, known simply as Furnace No. 1, is one of two that operated at Sloss. The original furnaces were built between 1881 and 1883, but were replaced in the late 1920s by the one you see today. The long open-side building attached to the furnace is the "cast shed." It was here that molten iron was originally "cast" into bars called pigs.
Making Iron in the Blast Furnace
The blast furnace worked twenty-four hours a day, seven days a week, so it was continuously being charged with raw materials and drained of it molten products. The furnace was kept filled to a stock line about six feet from the top. New material were added at the same rate at which iron and slag were produced.
The blast furnace operated on a countercurrent principle. Iron ore, flux, and coke were charged into the top, while hot air was blown into the bottom through openings called tuyeres. The coke in the charge passed
The freed iron formed drops which trickled into a pool at the hearth. Meanwhile, the flux soaked up the impurities from the ore and the ash from the coke to form slag. The slag ran into the hearth and floated on top of the molten iron.
About every four hours workers "cast" the furnace to remove the iron accumulated in the hearth. Iron was drained through the iron notch, a hole at the base of the furnace that was kept plugged with fireclay. A crew of workers drilled a hole through the clay, releasing the iron. The molten iron flowed down the curved runner and into the ladle car, which transported it to the pig casting machine. When the cast ended, the notch was replugged with clay using the mud gun. The slag was drained through a separate runner.
Location. 33° 31.24′ N, 86° 47.447′ W. Marker is in Birmingham, Alabama, in Jefferson County. Marker can be reached from the intersection of 32nd Street North and 2nd Avenue North, on the left when traveling north. Touch for map. This marker is located on the grounds of the Sloss Furnaces National Historic Landmark. Marker is at or near this postal address: 20 32nd Street North, Birmingham AL 35222, United States of America.
Other nearby markers. At least 8 other markers are within walking distance of this marker. Casting Pigs (a few steps from this marker); The Stock Trestle (a few steps from this marker); Stock Trestle/Tunnel (a few steps from this marker); Slag (a few steps from this marker); The Gas System (within shouting distance of this marker); Ironmaking (within shouting distance of this marker); Boilers (within shouting distance of this marker); The Blowing Engine Room (about 300 feet away, measured in a direct line). Touch for a list and map of all markers in Birmingham.
More about this marker. This marker can be found under Furnace Number 1's casting shed next to the furnace.
Also see . . .
1. Sloss Furnaces National Historic Landmark. (Submitted on October 7, 2013.)
2. Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham... The Historical American Buildings Engineering Record for the Sloss-Sheffield steel and iron facility. 135 photos, 20 drawings, plus a lengthy history of the facility. (Submitted on October 8, 2013.)
Categories. • Industry & Commerce •
Credits. This page was last revised on June 16, 2016. This page originally submitted on October 6, 2013, by Timothy Carr of Birmingham, Alabama. This page has been viewed 476 times since then. Photos: 1, 2. submitted on October 6, 2013, by Timothy Carr of Birmingham, Alabama. 3. submitted on October 8, 2013. • Bernard Fisher was the editor who published this page.