As per the system proposed in the 19th
century by Scandinavian archaeologists, the Stone Age
was followed by Metal Ages. Firstly, Bronze, and then
Iron. The Bronze Age developed between 4,000 and 2,000
B.C. Since it was more resistant than copper, bronze allowed
the manufacture of more rigid instruments and weapons.
The Iron Age is considered the last
technological and cultural stage of Pre-History. In Europe
and the Middle East, the Iron Age started around 1,200
B.C. In China, however, it had not started until 600 B.C.
The use of iron promoted great changes in the society.
Agriculture developed more rapidly because
of new tools manufactured. The confection of more modern
weapons allowed territorial expansion of several peoples,
what changed the face of Europe and part of the world.
From the observation of situations such
as the fires in the Neolithic Age, men figured out how
to extract iron from its ore. Iron ore started to be heated
in primitive ovens (ball oven), below its melting point
(temperature at which a material changes from solid state
into liquid). By doing this, it was possible to retrieve
some impurities off the ore, since they had a lower melting
point than the sponge iron This sponge iron was then worked
on an anvil to make weapons. To obtain 1 kg in iron bars,
it was necessary to use 2 – 2.5 kg of pulverized
ore and 4 kg of vegetable coal.
The first iron utensils were not very
different from those made of copper and bronze. However,
little by little, new techniques were discovered, making
iron harder and corrosion-resistant. An example was the
addition of limestone to the mix of iron ore and coal,
allowing better absorption of the ore's impurities. New
heating techniques were also developed, as well as the
production of more modern materials to work on already
cast iron.
