Presentation of a 19th century engraving representing the den of a blast furnace in Allevard (Savoy - France). This image fascinates us with the atmosphere it gives off.
This is an engraving of a blast furnace at Allevard (in Savoy -France) in the middle of the 19th century. We find it in "L'Album of the Dauphiné" released in the 1830s where Victor Cassien created numerous engravings.
Here is a brief description that he added to the engraving to transcribe the atmosphere that could be found there: "It is especially at night that we must consider this spectacle. A bell gives the signal, immediately the workers come running, everyone is at their post. [...]At a signal from the master foundryman, the iron bars are plunged into the opening of the crucible, the red cast iron rushes out [...]
At night, we have said, nothing is more majestic than the spectacle of the flow; this vast room lit by this stream of fire; these men, who, in the middle of the fire appear to be on fire, these sparks which fly from the furnace, all this has something strange, satanic, which makes us involuntarily dream of hell.
But what is a blast furnace?
The blast furnace is the second process for manufacturing iron after the primitive technique of the low shaft furnace.
The blast furnace is a technique that makes it possible to manufacture iron industrially. This revolutionary technique appeared from the 14th century in Europe.
The principle can be briefly summarized in 2 steps:
the 1st consists of manufacturing cast iron (iron 95% + carbon ~4% which is very high in quantity of carbon)
The blast furnace can reach thirty meters high. It is loaded with iron ore and coke from the top (mouth). Below, the "wind belt" brings warm air from a Cowper tower. The temperature in the belly reaches 1800°C.
the 2nd step consists of decarburizing the cast iron
The cast iron is placed in a new furnace then subjected to a lot of air: the oxygen burns the carbon and thus transforms the cast iron into iron.
A contemporary blast furnace in pictures :
Even today there are a few blast furnaces even if the majority of the iron we find is recycled and not manufactured.
For the most curious among you, here is a video from pamglobe which gives a nice visual overview of the activity of a blast furnace.
Source : https://www.pamglobe.fr/
