Hello, I'm trying to simulate the speciation of FeS systems and the solubility of a number of iron sulfide phases. I have successfully plotted activity predominance diagrams using Act2, but I am struggling with Phase2. I would like to plot the solubility of individual phases (e.g. mackinawite / pyrite) on pH/pe diagrams. However, I keep getting convergence errors. I have tried following the examples in the user guides, such as that for O2 solubility on a colour plot (this is what I would like for my system), but as soon as I replace the species for those I am interested in, it falls down.
data = thermo.tdat verify
conductivity = conductivity-USGS.dat
temperature = 25 C
H2O = 1 free kg
Na+ = 50 mmol/kg
balance on Na+
Cl- = 50 mmol/kg
swap HS- for SO4--
HS- = 1 mmol/kg
swap e- for O2(aq)
pe = -10
pH = 3
Fe++ = 10 umol/kg
scope y
fix pH
slide pe to 10
scope x
slide pH to 11
fix pe