Increasing the Effectiveness of the Bloomery Smelting Process by Using a Mobile Furnace Shaft—A New Furnace Type for the Early Roman Period in the Barbaricum?

This article deals with the experimental validation of an interpretation on the notable archaeological evidence patterns of early historical iron smelting in northern Central Europe. In this region, the inner Barbaricum, there was minimal evidence of iron smelting at the onset of the Roman Period. This shifts suddenly in the initial half of the first century AD: Numerous “centres of iron smelting” are identifiable in this region throughout this period. Numerous discoveries of iron smelting, known as “bloomery smelting furnaces”, are conspicuously clustered. It was formerly believed that the shafts of bloomery furnaces needed to be dismantled post-smelting to retrieve the produced iron. At the site “Sehnde 9” in Lower Saxony, Germany, it has been experimentally verified on several experimental furnace runs that the shafts can be reused, and these experimental results are consistent with the archaeological evidence from the site in question. The comparison with other Central European sites from the same period further substantiates that a reuse of bloomery furnace shafts was not an isolated phenomenon. This strategy markedly enhances the efficiency of iron production over time. Consequently, the designation of a novel furnace type “Sehnde” is suggested.