Ivor and Olive Lewis on mon 26 apr 04
Dear Friends,
Those interested in the Copper Solubility problem may wish to access the =
following web site.
Solubility of Copper in Silicate Melts as a Function of Oxygen ...=20
... Solubility of Copper in Silicate Melts as a Function of Oxygen and =
Sulfur Fugacities,
Temperature, and Silicate Composition. A. Holzheid and K. Lodders. ... =
solarsystem.wustl.edu/01abstracts.htm -
From my reading of the information which is about what happens beneath =
the Earths Crust I would infer the following propositions:
The solubility of Copper in a Silicate melt increases as the free oxygen =
content within the melt decreases.
We may infer that under atmospheric conditions high Oxygen concentration =
reduces the solubility of copper in a silicate melt. Perhaps =
observations which are being made show that copper oxide, in excess of =
minimal amounts, is not dissociating into Cu+ and O-- ions and that =
dissociation of either copper oxide is a necessary condition for entry =
of Copper Ions into solution in a silicate melt.
The solubility of Copper in a Silicate melt increases as temperature =
increases in the presence of Iron and Iron silicate at very low oxygen =
pressures.
I think there have been reports in the past about the necessity for Iron =
oxide as an adjunct additive in reduced Copper Red Glazes. Certainly =
many of the copper red recipes in Chappell include Red Iron Oxide as an =
ingredient.
Any other interpretations would be welcome.
Best regards,
Ivor Lewis. Redhill, South Australia
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