> What
> puzzles me is that if what McDonnell writes that up to 30% Sn ended up in the
> Cu in experiments done by one of his students in which cassiterite was added
> to molten Cu, then what is wrong with the thermodynamics or at least the
> calculations based upon the Ellingham plots of the oxidation/reduction curves
> for CuO and SnO!
I think Peter is right. If it works, it's because the charcoal covered
crucuble is very highly reducing. It's the carbon (or rather CO) that
is the reducing agent not the Cu. I have been able to reduce pure SnO2
in a clay/graphite crucible under charcoal at about 1000oC. This
implies a partial pressure of oxygen in the region of 10E-16.
Paul.
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Dr Paul Budd
Until 31st July 2000:-
Archaeological Sciences, Uni. of Bradford, Bradford, BD7 1DP, UK
Tel: +44 (0)1274 233554, Fax: +44 (0)1274 235190
Archaeotrace
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