PhreeqcUsers Discussion Forum

Solubility => Dissolution/precipitation => Topic started by: Tameka D on June 07, 2018, 09:02:27 PM

Title: Error: Expected saturation index
Post by: Tameka D on June 07, 2018, 09:02:27 PM
Hi everyone,

I am trying to model the dissolution of K2O and Na2O in a solvent similar to urine but keep running into the following, "Error: Expected saturation index".  Below are the phase keywords for K2O and Na2O.

K Oxide
   K2O + 2H+ = 2K+ + H2O
   log_k   84.14

Na Oxide
   Na2O + 2H+ = 2Na+ + H2O
   log_k   67.47

I'm not sure what is the cause of the error.
Title: Re: Error: Expected saturation index
Post by: dlparkhurst on June 07, 2018, 09:41:07 PM
The error is not in the PHASES data block. It is somewhere else. Try eliminating data blocks sequentially to identify the source of the problem.
Title: Re: Error: Expected saturation index
Post by: John Mahoney on June 07, 2018, 10:37:42 PM

The problem is the space in the name
you have


K Oxide  and Na Oxide. For comparison I fixed one of the names and I get

K_Oxide         -74.17      9.97   84.14  K2O
Na              -57.50      9.97   67.47  Na2O



PHASES appears to handle it (no error) but only as the letters before the space  hence the Na in the output above
but when you go to use them in EQUILIBRIUM_PHASES
it sees just K or Na as the phase name and then expects a number for the SI, but is sees "Oxide", where it expects a number.

so use an underscore or dash to complete the names
for K_Oxide. 
Title: Re: Error: Expected saturation index
Post by: Tameka D on June 08, 2018, 01:42:10 AM
Oh wow. Thank you guys!