CHAPTER SEVENTEEN
IRONWORKING IN THE
CELTIC WORLD
--.... --
W.H. Manning
A
lthough the Iron Age did not begin north of the Alps until the eighth century
BC, occasional iron artefacts had been appearing in central and western Europe
for some centuries before then. Some of these may have been made of meteoric iron;
others of metal acquired by a series of exchanges from the Hittite kingdoms of
Anatolia, where iron was being produced in appreciable amounts from at least the
middle of the second millennium BC, and in small quantities probably a millennium
earlier. But in some cases the iron may have been produced locally, for the furnaces
used to smelt copper could produce iron at only slightly higher temperatures.
Indeed, if iron ores were mixed with copper ore as fluxes to increase the copper yield,
metallic iron could be produced without any increase in temperature.
However, the ability to produce a material does not mean that it can or will be
utilized. For that to happen it must be possible to work it, and there must be a demand
for the products made from it; a requirement which may involve overcoming cultural
as well as technological barriers. The main difficulty in utilizing iron in a techno-
logical regime accustomed to working with copper alloys is that these were normally
shaped by casting the molten metal, whereas in European prehistory iron was a solid
worked by forging and welding at red-heat.
Two main changes may occur in the furnace when a metal is smelted. The first,
which is invariable, is the chemical reduction of the ore to the metal; in the case of
both copper and iron this occurs at c.800°C, At that temperature the metal is still a
solid and is intermixed with the siliceous residue of the ore. The second change,
which is not invariable, is the melting of the metal, which frees it from the siliceous
residue and concentrates it as a pool of molten metal. Pure copper melts at 1083°C,
pure iron at 153 5°c' A third process, whereby the silica from the ore combines
with some of the metal to form a molten slag, usually takes place at much the same
temperature. This has the advantage of partially freeing the metal from the non-
metallic residue but the disadvantage of reducing the yield, as a percentage of
the metal, often a high one, is lost in slag formation. In relatively sophisticated
metallurgical regimes this loss is reduced by adding a flux, another metal oxide, with
which the silica combines in preference to the metal being smelted. Whether this was
done in iron age Europe remains debatable.
The melting-point of pure iron is well above the maximum temperature attainable