Conceptual Models > Database selection and modification

Portlandite solubility high temperatures Pitzer

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Lola12:
Hello,
I'm looking for simulating the portlandite solubility in satured brine (NaCl, presence of Ca, SO4, Mg) from 25?C to 100?C. Comparing the different databases, none correspond to my issue.
Thermoddem.dat is not for high ionic strength (I=6in my case)
Phreescale.dat do not have sulfates
Pitzer.dat; portlandite solubility is not a fonction of the temperature. :
"Portlandite
   Ca(OH)2 =  Ca+2 + 2 OH-
   log_k      -5.190"


Could I do the following modifications in my code?

#solubility of portlandite at 100?C
Phases
Portlandite(mdf)
    Ca(OH)2 = Ca+2 + 2 OH-
   -analytics -1.05 -0.000344 -238.15 -3.39e-1 0 -1.6071e-5

If you know a database i can use, I am also interested

Thanks for your time

dlparkhurst:
Yes, I think it is reasonable to use the temperature dependence from another database for Portlandite. Here is a selection from some databases.

sit.dat
Portlandite
Ca(OH)2     = 1.000Ca+2     - 2.000H+     + 2.000H2O
     log_k    22.810     #10BLA/BOU1
     delta_h -130.078    #kJ/mol       
     # Enthalpy of formation:           -984.582        #kJ/mol       
     -analytic 2.13461E-2 0E+0 6.79444E+3 0E+0 0E+0

thermoddem
Portlandite
Ca(OH)2 + 2.000H+ = 1.000Ca+2 + 2.000H2O
     log_k    22.812     
     delta_h -130.108    #kJ/mol        #Internal calculation
     -analytic -2.8492926E+2  -4.4710612E-2  2.1380115E+4  1.0420455E+2  -7.5424917E+5
     #References = LogK/DGf: 10abla/bou; DHf/DHr: Internal calculation; S?: 98cha; Cp: 99aki/zot; V?: 95rob/hem;

minteq.v4
Portlandite
   Ca(OH)2 + 2H+ = Ca+2 + 2H2O
   log_k   22.804
   delta_h   -128.62   kJ

minteq, wateq4f
Portlandite
        Ca(OH)2 + 2H+ = Ca+2 + 2H2O
        log_k   22.675
        delta_h -30.69  kcal

llnl.dat, core10
Portlandite
        Ca(OH)2 +2.0000 H+  =  + 1.0000 Ca++ + 2.0000 H2O
        log_k           22.5552
   -delta_H   -128.686   kJ/mol   # Calculated enthalpy of reaction   Portlandite
#   Enthalpy of formation:   -986.074 kJ/mol
        -analytic -8.3848e+001 -1.8373e-002 9.3154e+003 3.2584e+001 1.4538e+002
#       -Range:  0-300

Lola12:
Thanks a lot. I will try it.

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