HOW transfer H2SiO3 to SiO2?

[yyyphreeqc]

I want to calculate the SI for K-mica, but I only have the data of H2SiO3. If I used the database"phreeqc", there only have the Si, which means I have to transfer the data of H2SiO3  to SiO2. SO, what can I Do? thank you!

[dlparkhurst]

To convert from SiO2(aq) to H4SiO4(aq), use the equation

SiO2 + 2H2O = H4SiO4, log K 0.

Write PHASES equations with SiO2(aq) for llnl.dat type databases, and H4SiO4(aq) for others. It depends on the definitions in SOLUTION_MASTER_SPECIES and SOLUTION_SPECIES in the database.

[MichaelZ20]

If in your measured chemical data silica is expressed as H2SiO3, you could merely sign this in the input file:

SOLUTION 1
-units  mg/l
pH 7 charge
Si 10 as H2SiO3
END

[dlparkhurst]

H2SiO3 is not defined in any of the PHREEQC databases. The llnl.dat type databases have SiO2 and others have H4SiO4. So, I am not sure exactly what you are trying to do. Why don't you include a simple version of a file that you are trying to run, even if it has errors. To be clear, it sounds like you are using the database phreeqc.dat.