The Blast Furnace

The Blast Furnace (HM1B40)

Location: Birmingham, AL 35222 Jefferson County
Buy Alabama State flags at!
Country: United States of America
Buy United States of America flags at!

N 33° 31.24', W 86° 47.447'

  • 0 check ins
  • 0 favorites

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.

The Process
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 down through the furnace almost unchanged until it reached the tuyeres. There it burned to form carbon monoxide, with the liberation of a large amount of heat. As the hot combustion gases swept up through the furnace, they heated the slowly descending stock and "reduced" the iron oxides in the ore. The chemical reactions that occurred during this process were quite complex. The basic reactions consisted of the combustion of coke to form carbon monoxide (2C + O2 - 2CO) and the reduction of iron oxides in the ore to yield metallic iron and carbon dioxide (Fe2O3 + CO - 2FeO + CO2; FeO + CO - Fe + CO2).

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.
HM NumberHM1B40
Placed BySloss Furnaces Historic Landmark
Marker ConditionNo reports yet
Date Added Wednesday, October 1st, 2014 at 4:43pm PDT -07:00
Sorry, but we don't have a picture of this historical marker yet. If you have a picture, please share it with us. It's simple to do. 1) Become a member. 2) Adopt this historical marker listing. 3) Upload the picture.
Locationbig map
UTM (WGS84 Datum)16S E 519428 N 3709030
Decimal Degrees33.52066667, -86.79078333
Degrees and Decimal MinutesN 33° 31.24', W 86° 47.447'
Degrees, Minutes and Seconds33° 31' 14.40" N, 86° 47' 26.82" W
Driving DirectionsGoogle Maps
Area Code(s)205
Closest Postal AddressAt or near 20 32nd St N, Birmingham AL 35222, US
Alternative Maps Google Maps, MapQuest, Bing Maps, Yahoo Maps, MSR Maps, OpenCycleMap, MyTopo Maps, OpenStreetMap

Is this marker missing? Are the coordinates wrong? Do you have additional information that you would like to share with us? If so, check in.

Nearby Markersshow on map
The Stock Trestle
0.01 miles
Casting Pigs
0.01 miles
Stock Trestle/Tunnel
0.01 miles
0.02 miles
The Gas System
0.02 miles
0.03 miles
0.04 miles
The Blowing Engine Room
0.05 miles
Sloss Furnaces
0.06 miles
Duncan House
0.1 miles
Check Ins  check in   |    all

Have you seen this marker? If so, check in and tell us about it.

Comments 0 comments

Maintenance Issues
  1. Is this marker part of a series?
  2. What historical period does the marker represent?
  3. What historical place does the marker represent?
  4. What type of marker is it?
  5. What class is the marker?
  6. What style is the marker?
  7. Does the marker have a number?
  8. What year was the marker erected?
  9. This marker needs at least one picture.
  10. Can this marker be seen from the road?
  11. Is the marker in the median?