Example 12. High temperature
Data for the chemical system H+, e−,
Au+, HS− and
Cl−
was extracted using DATABASE setting the
temperature to 250°C.
In SPANA the chemical system was
modified in to
exchange components for reactions,
in this case e− was exchanged for O2(g),
and HS− for H2S (without
a phase indicator, it means that
H2S is aqueous, dissolved).
By making O2(g) one of the components,
it is possible to make a diagram with
log PO2(g) in the vertical axis.
This type of diagrams is common in geochemistry. Note that fugacity and partial pressure
have the same relationship as activity and concentration.
This diagram shows the 50 ppb contour for the solubility of gold at 250°C (sulfide
aqueous complexes in this case).
See also: example 11 (another high-temperature diagram).
Back to: example files
