R A F Ixer wrote:
> My understanding is that the two carbonates, rosasite and
> aurichalcite are mineralogical curiosities rather than ores.
> If you wanted to make brass with carbonates why not use
> smithsonite (calamine in USA) and malachite/azurite- both
> abundant minerals familiar to ancient metallurgists and both form
> ore deposits....
Under moderate redox conditions (p.ex. smelting of matte), ZnO
accumulated in the upper parts of a "primitive" furnace during the
reduction of Zn-bearing ores. The resulting product see
http://www.uni-mainz.de/FB/Geo/Geologie/archaeo/Iran/Kavir3Abb28.html
Thus ZnO should have been widely available. There seems to be no
difficulty to make brass by coheating copper + ZnO under reducing
conditons (together with carbon, Zwicker and Breme 1988). The question
is, when this first has been observed and used to produce a new
metal/alloy.
Ingo Keesmann
__________________________________________________________
Arbeitsgruppe Archaeometallurgie
Institut fuer Geowissenschaften
Johannes Gutenberg-Universitaet Mainz
D-55099 Mainz (Germany)
Telefon (+49) 6131 39 3 0181
Telefax (+49) 6131 39 2 3070
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http://www.uni-mainz.de/FB/Geo/Geologie/archaeo/
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