11-21-2013, 02:36 PM
The scale of the (Etruscan) iron production at the site of Populonia, on the mainland across from Elba which was rich in iron ore, seems truly staggering. According to Theodore Wertime (1983, p. 451) between 500 and 100 BC, an estimated 4 million metric tons of iron were produced. This would mean an average output of 10.000 t per year. Wertime gives the following figures for the iron-smelting process (in million t):
slag: 2-4
charcoal: 1.5-3
coppice: 1.5-3
This means that the ratio between the slag, which was recorded at the site before it was reworked in the 19th century, and the iron end product is 0.5-1 to 1.
By contrast, another estimate is offered by David Gill (1987): "The slag-heaps from iron-working are estimated as weighing 2 million tons, with an estimated annual extraction of ore at 10-12,000 tons over four centuries. If 8 kg of iron can be produced from 50 kg of ore then this represents an annual production of 1.600-2.000 tons of iron."
Even taking into account that he assumes the slag-heap to be only half as big as Wertime, Gill arrives at a much lower figure. Which estimation is more viable and what is a realistic ratio between iron ore, iron and slag for ancient iron-smelting?
slag: 2-4
charcoal: 1.5-3
coppice: 1.5-3
This means that the ratio between the slag, which was recorded at the site before it was reworked in the 19th century, and the iron end product is 0.5-1 to 1.
By contrast, another estimate is offered by David Gill (1987): "The slag-heaps from iron-working are estimated as weighing 2 million tons, with an estimated annual extraction of ore at 10-12,000 tons over four centuries. If 8 kg of iron can be produced from 50 kg of ore then this represents an annual production of 1.600-2.000 tons of iron."
Even taking into account that he assumes the slag-heap to be only half as big as Wertime, Gill arrives at a much lower figure. Which estimation is more viable and what is a realistic ratio between iron ore, iron and slag for ancient iron-smelting?
Stefan (Literary references to the discussed topics are always appreciated.)