Last Charcoal Smelter in Germany
|Schmalkalden is a small "city" with
about 20.000 inhabitants smack in the exact middle of Germany (also known as "the (very pretty) sticks"). It boasts
"Wilhelmsburg Castle", the former residence of the Hessian landgraves (sort of dukes), built about 1590 and containing
interesting things. Its claim to fame comes from
the Schmalkaldic League, a historically important military alliance, founded in 1531
by "early" Protestant princes, for protecting religious and political interests within their domains.
The area has a long standing history of mining, metal smelting and metal working, going back to at least 1300. The guns made in nearby Suhl, for example, have been world-famous for quite some time. Close to Schmalkalden is the "Neue Hütte " (New Smelter), now an open-air museum.
|The "Neue Hütte Schmalkalden" (New Smelter of Schmalkalden) was raised in 1835 and produced pig iron until 1924 - with charcoal! That makes it the last charcoal-run smelter in Germany, if not in Europe or the world
|You would not necessarily recognize the smelter for what it is. From the outside it is just a solid wooden framework building:
|The inside, however, contains a rather massive smelter made from solid stones. The picture below shows the lowest part, the "hearth" where the liquid metal came out
|A detailed model in the museum gives a good feeling for the over-all construction, and a brochure informs about he working principle of the smelter:
|Note that the narrowing of the cross-section above the reaction zone provides for some mechanical support of the fuel / flux / ore filling by friction and some mixing of the contents by "folding".
|The product of the smelter is rather unspectacular. It is pig iron, produced in plates:
|Around 1900 the rest of the world had been using coke
for quite some time, but Schmalkalden stuck to charcoal. Charcoal is more reactive than coke and thus offers certain advantages
for smelting but supply relies on the wood available, and forests near a major smelter will be depleted soon enough. Transportation
of charcoal over long distances is not very economical since it has a low density, and transport costs typically scale with
the volume, not the weight.
In antiquity it was thus easier to move the (small) smelters to a new woody area than to transport charcoal for distances larger than about 10 km.
|The Schmalkalden smelter, however, like all smelters just a few hundred years old, was tied
to its source of energy: a waterwheel supplying the power for blowing enough air into the tuyeres. In addition, you needed
the ore and that was mined in the general region.
Somehow, albeit with large difficulties, the supply of charcoal was kept up until less than a hundred years ago. I guess it was either charcoal or closing down the whole industry because transportation of coke from (far away) coal mining areas would have been too costly.
|The people running the smelter had clear ideas about the precise composition of the burden, the mix of ore, flux and charcoal, that went into the "Gicht", the feeding opening on top:
|Some numbers of interest for the smelter are:
|This is a rather peculiar iron. Very rich in Manganese (Mn) and with a carbon concentration that is relatively low for cast-iron. It might have been well-suited (after some fining in order to reduce the carbon content somewhat) for the production of tools like hammer heads, drill bits, screw driver blades, wrenches etc., a major local industry needing particularly hard steel, or for casting oven parts.
History of Carbon
Critical Museum Guide: Museums in Istanbul, Turkey
Steel Revolution. 1. The Kelly - Bessemer Process
Smelting Science - 1. Furnaces
Large Pictures chapter 11.4
Smelting Science - 5. Smelting Details 2
10.1.3 Smelting, Melting, Casting and Alloying Copper - The Second
10.5.4 Making Steel Things
Old Iron Things
Smelting Science - 2. Charcoal Technology
Hardware Around the Making of Metals and Their Proper Names
11.6.2 Making a Japanese Sword - Part 1
Smelting Science - 3. Smelter Technology
Smelting Science - 4. Smelting Details 1
Rosh Horesha, Shanidar Cave
© H. Föll (Iron, Steel and Swords script)