Is it possible to calculate SI of a mineral without having an element analyzed?

[toupis12]

Hi,

I am running a 9 month leaching experiment and analyzed the basic cations over the time and would now like to calculate the SI of a handful of minerals as they change over this time span. The issue I just ran into is, I would like to add minerals for which I do not have all the elements analyzed (F, P, and K, as I used some potassium in the experiment).

Is it possible to set an uncertainty for the given elements so that the thermodynamic calculations essentially consider it as non-limiting and worry about the others, similar to inverse modeling? Clearly it wouldn't be "true" or "correct" but it would still be an interesting piece of information for my project.

Thank you very much,
Best,
Jonas

[dlparkhurst]

You can estimate a concentration by assuming a mineral is in equilibrium. The following estimates the concentration of F needed to be in equilibrium with Fluorite.

Code: [Select]

SOLUTION
Ca 1
F  1 Fluorite 0.0
END
Of course you can always simply assign a concentration as well. In either case, it might be hard to justify the result for a publication.