It is known that men have known of iron for around 4000 years. However, for most of history Iron was very hard to extract from the ore. Only very small amounts of Iron could be obtained because the ore would be heated over a small fire. It was discovered that it would be necessary for the fire to be hotter to produce larger amounts of Iron. Eventually, a bellows system was created and the fire became hot enough to produce more iron per batch.
When iron ore was heated in these fires it would slowly change into a lump of iron that could then be hammered into the shape that was desired. When heated in these furnaces sometimes if not properly taken care of the iron would turn to a liquid state. This iron was then scrapped. Later in the 1500’s however, liquid iron was the goal.
As power from water wheels became more popular across Europe some iron workers developed a bellows that was powered by water. This bellows blew much more air and let the fire reach much hotter temperatures than the man powered counterparts. Using water power iron was easily turned to liquid form. It was found that iron ore always contained contaminates that would not allow the final product to be pure. Iron workers discovered that when limestone was added it would pull the contaminants out of the liquid iron and would form a lighter liquid which would then flow off of the liquid iron.
The pure liquid iron would then be poured into casts on the floor. These casts were long bars with shorter bars on right angles to the main chute. This shape reminded the iron workers of piglets suckling on their mother and deemed this type of cast iron pig iron.
The furnaces used in the production of cast iron were called blast furnaces. It was discovered that wood would not work for the production of cast iron and that charcoal would have to be used. Charcoal had a disadvantage however. It was very hard to produce at high quantities. The production of coal was then increased due to the push from the iron industry. Eventually, coal was put through a process similar to that of charcoal to produce coke. Coke is an even more efficient form of coal with less contaminants which would produce a better product.
Here is a very good source if you want to learn more
Word Count : 417
Iron Slag: https://en.wikipedia.org/wiki/Slag#/media/File:Slag_from_iron_ore_melting.jpg
Pig iron: https://en.wikipedia.org/wiki/Pig_iron#/media/File:Casting_pig_iron,_Iroquois_smelter,_Chicago.jpg
Water wheel bellows:
4 Replies to “The Iron Revolution”
Great article! I enjoyed all the information about how the process of iron production became easier and easier with technology. One thing that kinda stood out to me was that the name for pig iron came from the ironworkers thinking that the produced bars of iron resembled piglets. I wonder if the term pig iron was widespread or if it took off in one spot and the name spread. In the article that you provided, I saw that addition techniques such as the puddling and rolling which got all of the impurities our of iron and allowed for a vast increase in mass production. Are these techniques still in use today or has iron production continued to change over time.
Nice job on the blog post. The evolution of iron working was truly fascinating. You gave a very detailed explanation of the different types smelting processes. The links you provided were very interesting and helped to strengthen your blog post
Great Job Again!
This article is interesting and iron has even more of an interesting history. Metal casting cannot be written off as a medieval invention because it has been happening in Mesopotamia in 3500 BC to make trinkets. Cast iron was invented in China in the 5th century BC and poured into molds to make plowshares and pots as well as weapons and pagodas. Although steel was more desirable, cast iron was cheaper and thus was more commonly used for implements in ancient China, while wrought iron or steel was used for weapons. The technology can be said to have traveled along the silk roads as a iron casting industry was found in the Alburz mountains in the 13th century. However, it seems that this technology really took hold in Europe only around the time when bombards became a big thing in siege warfare. For example, one of the first commissions for cast iron came from Henry VIII to create a cannon and shot.
There’s actually a pretty cool pig iron forge in this part of Virginia that I’ve been to. There’s a class offered at VT called History of Virginia and in the class we traveled around southwest Virginia on a field trip and one of the places we stopped was a forge. It was cool to learn more about iron and to learn why pig iron got its name.