Slag washing (upper boiling)

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"Eisenschmidt" at the origin of the Kocher on the map of the Heidenheim Forest from 1590

From 1745 slag washing was a district of Oberkochen , which was at the origin of the black digester and disappeared at the beginning of the 20th century .

Iron mining from 1551 to 1644

Award document of the Prince Provost Heinrich of Ellwang from October 26, 1551 for Peter von Brogenhofen

Called Peter von Brogenhofen, Vetzer, acquired on 26 October 1551 by the Ellwanger Prince Provost Henry of the Palatinate for ten florins a year the right, at the origin of the digester, "a melting furnace, hutten sampt a leuterfeur uffzerichten." This smelter nearly a century long made of iron ore, malleable iron and cast iron .

Blast furnace and lauter fire

In a wood -fired blast furnace , Bohnerz from Zahnberg near Königsbronn and from the Nattheimer area as well as Stuferz from Aalen was smelted. The fans of the blast furnace were driven by an undershot water wheel in an artificially created digester channel. From the blast furnace came the rag , a red-hot, doughy lump of iron still interspersed with charcoal residues. This was decarburized in a lautering fire and mainly poured into ingots , which were called pigs .

In 1565, 32 quintals of stove pieces, 396 quintals of stove plates, 55 quintals of balls and 4788 quintals of iron were produced in Oberkochen. That was a total of 5,271 huts , which at the time was equivalent to 115 pounds (≙ 57.5 kilograms ). Even with today's conversion factor of 50 kilograms / hundredweight this was 263 tons of iron, which, given the weight of iron (7.87 g / cm³), can be imagined as a cube with an edge length of 3.2 meters.

For the year 1569, 5679 quintals (284 tons) are recorded for Oberkochen in the profit statements at the time, while the neighboring ironworks in Königsbronn even produced 9394 quintals (470 tons) in the same year. All of this was associated with an enormous demand for wood for the firing of the blast furnaces and lautering fires, so that it was not the ore, but the wood supply from the neighboring forests that was a constant bottleneck.

Slag epoch and slag washing

When iron is produced in the blast furnace , a slag called mineral melt residue is created. A blast furnace produces around 200 to 300 kg of slag per ton of cast iron, whereby the slag proportion of the Bohn and Stufer ore used at that time in Oberkochen with its low iron content must have been even higher. Because it was fired with charcoal, the furnace temperature was relatively low back then. Therefore the Oberkochen slag contained a not negligible amount of residual iron. This iron could be used by smashing the slag in a slag pound (pounding = knocking, stamping), then crushing it and washing the iron from the fine slag sand with water. The remaining iron was melted down again. According to today's parlance, slag washing was a recycling plant for cast iron. What happened to the crushed slag is not known. Nowadays they are used as an additive for cement , in road and path construction as aggregate or as a mineral fertilizer . At least there is evidence of a slag substructure for the Tiefentalstrasse in the south of Oberkochen.

Checkered history until the end of the Thirty Years War

In 1564 the smelter on the Kocher was sold and then had an eventful history with owners who frequently changed hands.

On a map of the Heidenheim Forest from 1590, this steelworks is marked as "Eisenschmidt" at the "Kochensuhrsprung" near "Oberochen". The term “iron forge” was also used as a synonym for “iron smelt” and therefore does not necessarily indicate that the pig iron was actually processed in a forge there.

During the Thirty Years' War , in which the population of Oberkochen fell from over six hundred to one hundred, the “smelting furnace, iron smithy, slag poke and laboratory technician's house” went under, the main reason being the lack of wood. The furnace was demolished in 1644 and instead a new one was built between 1645 and 1650 in Unterkochen.

Slag washing from 1646

After the ironworks closed in the Thirty Years War, the remaining slag heaps south of the Kocherquelle were still used. For this purpose, between 1646 and 1649, a new slag washer was built directly on the Kocherkanal.

Prahl slag washing on the map of the Prince Provost of Ellwangen by Arnold Friedrich Prahl from 1746 (detail)

In 1745 Arnold Friedrich Prahl, master builder of the Prince Provost's Ellwangen , to whom slag was left from the Prince's ironworks, had the slag washing facility rebuilt. However, their operation was given up after a few years.

The slag washer was then used as a residential building and is shown in an original map from 1830 with the house number "Oberkochen 127". In the records of the State Surveying Office, two families are named as owners for 1830: the Josef Hägele family, carpenter, and the Michael Traber family.

The corridor to the south of the Kocher origin, on which there is an agricultural property (Heidenheimer Strasse 140) today, is referred to in another version of the original map from 1830 as the "Schlackenweg". This name has to this day for the local Won received.

The building was enlarged between 1830 and 1840. In 1854 slag washing was described as "a house at the origin of the digester, where a so-called slag path and a smith dump are also to be found". The slag washing plant had fourteen Catholic residents at that time (Oberkochen: 1,180 residents, 705 of them Catholics).

In the period that followed, the hermit's house at the origin of the Kocher seems to have gone downhill. The building was last mentioned as inhabited in 1906 and at that time still had five residents. It was demolished shortly afterwards, in 1907 at the latest.

Name "Black Cooker"

The name of the black cooker is said to come from its dark river bed. This color comes on the one hand from the rotting water plants, but above all from the dark cinder blocks on its bottom, which come from the former smelting furnace.

Fools guild "Schlagga-Washer"

The Oberkochen fools' guild "Schlagga-Wäscher", founded in 1973, derived the name of their carnival club from these historical contexts. The “Schlagg”, the “Wäscherle” and the “Miniwäscherle” stand as symbolic figures for the then newly created customs. This choice of name is also a play on words with the Swabian dialect "Schlagg", which stands for a good-for-nothing.

Forged stone above the origin of the stove

The name of the "Schmiedestein" (also: "Schmidtestein" or "Schmiedefels"), a rock group directly above the source of the Kocher at 620 m above sea level, also reminds of the earlier iron smelting. NHN, in which there is a cave designated as a cultural monument . It is a dolomite rock group in the White Jura , where bizarre shapes have emerged as a result of the rock's different weathering stability .

photos

  • Origin of the black cooker south of Oberkochen

  • Black cinder blocks found at the source of the stove in the river, some with reddish iron residues

  • The fool's tree in the center of Oberkochen is crowned every year by the “Schlagg” of the Oberkochen fools' guild

  • "Schlaggawäscher" of the Oberkochen fools guild

  • Forged stone, the name of which is reminiscent of the earlier iron smelting at the origin of the stove below the rocks

  • Wrought stone cave

Web links

Commons : Slag washing in Oberkochen  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Slag washing - desertification in the local dictionary on leo-bw.de. Retrieved January 12, 2018
  2. ↑ Manfred Thier: History of the Swabian Hüttenwerke. A contribution to the economic history of Württemberg. 1365-1802. Aalen / Stuttgart 1965, p. 45.
  3. ^ State archive Ludwigsburg B 389 U 1073 and U 1074 .
  4. ↑ a b c d e f g h Dietrich Bantel: The "slag wash" at the origin of the stove on heimatverein-oberkochen.de. Retrieved January 12, 2019.
  5. ^ City of Oberkochen (Ed.): Oberkochen . Oberkochen 2018, p. 178.
  6. ^ Marika and Joachim Kämmerer: From the village to the industrial community. A look back at the almost 450-year industrial history of Oberkochen . In: City of Oberkochen, Mayor Harald Gentsch (Ed.): Oberkochen - history, landscape, everyday life. Oberkochen 1986, pp. 129–162, here: pp. 129–130.
  7. ↑ a b Thier p. 55.
  8. ↑ On the Schlackenpoche see also: Schlackenpoche in miniature format at the pond on wp.de. Retrieved January 26, 2019.
  9. ^ Heidenheimer Forst in: Chorographia description of the praiseworthy principality of Württemberg on leo-bw.de.
  10. ^ Christhard Schrenk : Alt-Oberkochen. Stories and reports from Oberkochen's past. Oberkochen 1984, p. 81.
  11. ↑ a b c d Royal Statistical-Topographical Bureau (ed.): Description of the Oberamt Aalen . Stuttgart 1854, p. 92 .
  12. ↑ Thier pp. 188-189.
  13. ↑ a b Dietrich Bantel: Iron forge at the origin of the cooker on heimatverein-oberkochen.de. Retrieved January 12, 2019.
  14. ↑ Oberamt Aalen p. 297 .
  15. ↑ Oberamt Aalen p. 291 .
  16. ↑ Alfons Mager: The cooker - a natural monument . In: City of Oberkochen, Mayor Harald Gentsch (Ed.): Oberkochen - history, landscape, everyday life. Oberkochen 1986, pp. 335-338.
  17. ^ Website of the Narrenzunft Oberkochener Schlagga-Wäscher eV
  18. ↑ Schlagg in: Swabian dictionary on stuttgarter-nachrichten.de. Retrieved January 12, 2019.
  19. ↑ Dietrich Bantel: The four largest Oberkochen caves. In: City of Oberkochen, Mayor Harald Gentsch (Ed.): Oberkochen - history, landscape, everyday life. Oberkochen 1986, ISBN 3-9801376-1-9 , pp. 286-292 , here: p. 288.
  20. ↑ Dietrich Bantel: The cave in the forged stone on heimatverein-oberkochen.de. Retrieved February 26, 2019.

Coordinates: 48 ° 46 ′ 20.3 "  N , 10 ° 5 ′ 46.3"  E