How does ordinary primitive smelting of iron differ from bloomers iron smelting?
Who smelted iron earliest? Tell Hammeh or Çatal Höyük site in Anatolia
From Wikipedia (but it doesn’t help me understand the difference between the processes and there are many websites challenging Çatal Höyük site in Anatolia as the ‘cradle’ of iron smelting.
The Iron Age in the Ancient Near East is believed to have begun with the discovery of iron smelting and smithing techniques in Anatolia or the Caucasus and Balkans in the late 2nd millennium BC (c. 1300BC).[15] The earliest bloomery smelting of iron is found at Tell Hammeh, Jordan around 930BC (14C dating).
Lemme have a shot, though I’m not a metallurgist. You smelt simply by removing the oxygen from the iron oxide. Take magnetite sand, Fe3O4. You can remove the oxygen and produce iron/steel in a small charcoal fire with enough air blown into it (1,200 degrees centigrade.) Unfortunately, with this method, you produce inconsistent lumps from the furnace: un-smelted magnetite, iron, low- and high-carbon steel.
The above method is really a hit-and-miss process, and you have to test each lump of steel that comes out for the right carbon content. Some improvements in insulating the smelt within a clay vessel (crucible or wootz steel) were done but the result was the same. Once you have enough steel of the right carbon content, it’s up to you to do what you want with it, whether to forge each piece, or pattern-weld several pieces, or stack/layer forge them. The Japanese tataras that produce sword-quality steel are like this. They produce a non-homogenous lump that has to be broken up and the fragments sorted.
In the blooming process, you produce molten steel of the right carbon content you want and pour it into a mold to form a block or a bloom, from where you can shape it into the form you want (like sheets). Plate armor for knights was possible only with the blooming method. Before that, you had only steel rings and small greaves for armor material. How to produce a bloom? Easy, heat to past 1,600 degrees, which was beyond most charcoal hand-blown furnaces during ancient to post-medieval time. Find a way to separate the molten silicates (slag) from the un-smelted oxides and iron (matte) from the molten steel. You are looking to tap the molten steel last and mold it into your bloom.
Producing bloom steel was one major step in man’s march to industrialization.
I’m unaware of *any *claim of *iron *smelting at Çatalhöyük. There’s a lot of debunking of the claims for *copper *smelting (and the use of *native *copper is undisputed), and there’s more credible claims of *lead *smelting, but no iron. Perhaps a few links?
Wikipedia will lead you to this nice discussion of iron, going all the way back to a smelted iron dagger blade at Alaca Höyük in 2500 BC, at a time when iron was more precious than gold.
From a historical viewpoint, I think the first smeltings are less important than the mass production when bloomery smelters were finally mastered. Awareness of iron smelting had been around for centuries, but it was difficult.
I’ve read that iron technology was spurred by the soaring cost of bronze when the fall of the Hittite Empire disrupted the importation of tin from the east.
No, as far as I’m aware the existence of an iron-smelting industry there is not controversial at all. Like I said, the discrediting I’ve seen lately is about copper smelting, at Çatalhöyük.
I think I see where you’re experiencing some possible confusion - nobody thinks Tell Hammeh is the oldest iron smelting. It’s just the earliest bloomery we have found. We don’t really know how the earlier Anatolian iron was smelted, AFAIK. Probably bloomery working as well, though, or possibly something more complex as a by-product of copper smelting.
Definitely not. The Chinese did create the first blast furnaces, way before the West. But other than one very recently-found Qijia-period (~1400 BCE) bloomery artefact , Chinese iron’s generally dated to the 800s BCE, 600 BCE for the blast furnaces. There’s some debate (see 2.3) over whether iron smelting was introduced or developed locally.
It’s sometimes difficult to see where things were smelted because the objects can get dispersed through trade over a wide area, because they who smelt it dealt it.
The biggest difference between primitive smelting bloomer smelting is one of size and control. Primitive smelting would occur with a small charcoal fire, generally using natural convection. Temperatures would be limited and the result was a small lump of iron, fist-sized or smaller. These lumps could be reheated and beat with a hammer to shape and to remove entrapped slag. This was useful for small wrought iron items, axe heads, knives, arrow shafts and points.
A bloomery would be larger, perhaps bushel-sized or larger. Generally, a bloomery would have a means to blow air into the charcoal-ore fire to speed things up and produce a more uniform result. This would also produce a larger lump of iron, so larger reheating facilities, hammers, and handling equipment was needed. With larger “blooms”, larger pieces of wrought iron could be made.
I can’t help with the archeological side of your inquiry.
I’ve read that iron technology was spurred by the soaring cost of bronze when the fall of the Hittite Empire disrupted the importation of tin from the east.[/QUOTEn
Yes, the tin trade was critical to bronze production. Tin in usable form is uncommon and tin dealers are believed to have traveled and traded over long distances.
This is the earliest example of the now-established truism that “he who smelt it dealt it.”
