For those of you who are willing to read the original German texts, try:
Gassmann, G., Yalcin, Ue & Hauptmann, A., 1995, Fruehmittelalterliche
Eisenproduktion in Kippenheim, Suedbaden: ein missing link zwischen
Rennverfahren und Roheisentechnologie. Metalla (Bochum) 2, 43-52.
This describes 8/9 c AD smelting of lime-rich, limonitic iron (hydr)oxide
ore resulting in a glassy slag of about 40% SiO2, 10% Al2O3, 20-30% CaO, and
only 15-25% FeO. Site in southwest Germany (Baden). The metal produced (as
far as we can tell from the prills left behind in the slag, and in lumps)
had 2-4% carbon. SiO2 was probably added as a flux to the ore, or from
erosion of the sandstone used to build the furnaces.
Yalcin, Ue. & Lychatz, B., 1995, Frueh- und hochmittelalterliche
Eisengewinnung im Vorland der mittleren Schwaebischen Alb:
Naturwissenschaftlich-technologische Aspekte zur Rekonstruktion der
Eisenverhuettung, Metalla (Bochum) 2, 53-61.
This discusses the intentional production of pig iron in the 11/12 c AD
elsewhere in SouthWest Germany, with a number of sites of different dates
being investigated with slags spanning from more bloomery-type (Roman) to
glassy (Medieval), as low in FeO as 5-10 wt%, using the same ore. The carbon
contnt in the iron is estimated to 2-3 wt%.
The full story is in
Yalcin, Ue & Hauptmann, A., 1995, VIII. Archaeometallurgie des Eisens auf
der Schwaebischen Alb, in: Beitraege zur Eisenverhuettung auf der
Schwaebischen Alb, Forschungen und Berichte zur Vor- und Fruehgeschichte in
Baden-Wuerttemberg 55, Stuttgart, 269-309.
This has loads of micrographs of metal and slag, chemical analyses of slags,
ores and metal, ternary diagrams and other goodies. Lots of P for those who
are really into it.
Zinc:
The 'Roman' zinc tablet which Peter Northover kindly mentioned is published
briefly in English in the Proceedings of the Archaeometry symposium 1994
(Ankara), as Rehren, Th., 1996, A Roman zinc tablet from Bern, Switzerland:
reconstruction of the manufacture, in: Archaeoemtry 94, 35-45.
Again, the full story is in German, published only last year as
Fellmann, R., 1999, Das Zinktaefelchen vom Thormebodewald auf der
Engehalbinsel bei Bern und seine keltische Inschrift, in Archaeologie im
Kanton Bern 4B, 133-175 (which has an analytical chapter by W. Stern & A.
Burkhardt on the chemical composition, p. 157-160, and an
archaeometallurgical one by myself, on page 160-168). Basically, it is a
cast zinc object, nicely corroded, with some lead, copper, iron etc. as
impurities, and a most interesting zinc-iron skin developed where the metal
was cast (probably) into an iron mould. The authenticity of this find is now
beyond doubt (we believe), due to unique inscriptional evidence from the
tablet, and a number of previously unpublished small statues from the same
sort of celtic region of south-west central Europe.
The number of further 'Roman' zinc finds is legion (well, sort of...), with
some of them looking surprisingly good to my opinion, but few if any are
properly published.
I'll be happy to provide xeroxes of the more obscurely published pieces...
Thilo
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