I have no knowledge of anyone doing the experiment, but what standard free energy did you use for CuO? I looked in Woods and Garrels and the variation between the last cited NBS data and the Woods&Garrels redetermination is 4 kJ, which might make a difference.
>>> <[log in to unmask]> 04/22 9:21 AM >>>
The subject of producing bronze (10% Sn) by adding cassiterite to molten Cu
has again arisen. I have maintained for some time now that calculations based
upon the thermodynamics (primarily the Ellingham diagram) indicate that no
more than about one or two per cent Sn will end up in the solidified alloy.
This is because the kinetics of reducing SnO ( SnO to Sn by the Cu) are close
to those for oxidizing Cu to CuO and simultaneously reducing CuO to Cu by the
Sn. The net result is to produce about one to two per cent Sn.
I have been told that there are results from some experiments indicating that
these calculations are deceiving and that a normal bronze (that is, 10% Sn in
90% Cu) can be obtained (solely by adding cassiterite to molten Cu). Does
anyone know of such experiments?
R. Maddin
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