Germans Smelting Iron

These figures are to be used for the whole of Central Europe.
As early as the Middle Bronze Age, from 1200 BC, the gradual replacement of bronze by iron began, the extraction of which became possible - although by today's standards still in a rather simple way - once the necessary basic principles had been learned. For the reductive production of iron from iron ores, significantly higher temperatures were needed than for the extraction of copper or bronze. With the available fuel and reducing agent charcoal, this required a special design of the smelting furnaces in terms of air supply in order to reach the necessary temperatures. Thus, the iron was initially only produced in sintered (not molten) form, as so-called slugs, because the melting temperature of the iron of 1535 °C could not be reached with the available furnaces. Moreover, there were no processing techniques for pig iron, which could not be shaped by forging. It was only through techniques such as carburising, hardening and tempering that it was possible to obtain iron-carbon alloys and thus steel, which gradually replaced copper or bronze.
The racing furnace was in the form of a small shaft furnace with a height of about 50 to 220 cm and was built of clay or stones. Next to the shaft, in some cases, there was a hearth pit for the slag drain, the racing pit. Racing furnaces were heated with charcoal, wood or peat and then filled for smelting from above in alternating layers with fuel, usually coal from coniferous wood, and finely crushed ore with as high an iron content as possible. - Wikipedia -