PhreeqcUsers Discussion Forum

Beginners => PHREEQC basics => Topic started by: jlucas91 on May 27, 2020, 06:16:58 PM

Title: How do you obtain the explicit amount of precipitant from a modeled reaction?
Post by: jlucas91 on May 27, 2020, 06:16:58 PM
Greetings,

I am a student trying to learn how to operate PHREEQC. I am modelling simple situations so that I can keep a hand on whether the output is reasonable or not.

To that end I am attempting to precipitate barite from a solution of barium chloride using sodium sulfate. I believe my input does this however I would like to get an explicit section in the output that states how much material is in the solid phase after the reaction. Is there an additional command I could use to get the information I am after explicitly? My input is given below.

SOLUTION 1
    temp      25
    pH        7
    pe        4
    redox     pe
    units     mmol/kgw
    density   1
    -water    1 # kg


REACTION 1
    BaCl2      1
    10 millimoles in 1 steps
SAVE solution 1

END

USE solution 1

REACTION 2
    Na2SO4     1
    10 millimoles in 2 steps
EQUILIBRIUM_PHASES 1
    Barite    0 0

END


Thanks
Title: Re: How do you obtain the explicit amount of precipitant from a modeled reaction?
Post by: dlparkhurst on May 27, 2020, 06:34:44 PM
If you were to look at the output file, you would find the following section (from last step). You interpret it as follows: there were no moles of Barite initially, after the reaction there are 9.979e-3 moles of barite, and the amount of barite that precipitated in this step is 9.979e-3 (positive indicates an increase [precipitation] in the amount of barite).

Code: [Select]
-------------------------------Phase assemblage--------------------------------

                                                      Moles in assemblage
Phase               SI  log IAP  log K(T, P)   Initial       Final       Delta

Barite           0.00    -9.84     -9.84    0.000e+00   9.979e-03   9.979e-03

There are also options in SELECTED_OUTPUT and Basic functions in USER_PUNCH (EQUI("Barite") and EQUI_DELTA("Barite")) to get the information in a selected output file.
Title: Re: How do you obtain the explicit amount of precipitant from a modeled reaction?
Post by: jlucas91 on May 27, 2020, 06:49:45 PM
Thanks Dr. Parkhurst. I was aware of the phase assemblage section however I am looking for a way to have it stated in a direct fashion. I'll work with the SELECTED_OUTPUT and the basic funtions to see if I can get the format I am looking for.

It is a huge help to even be pointed at commands that could help.

Thanks again!