Author Topic: Precipitation of calcite and calcium hydroxide with ammonia (Read 4090 times)

tatsu · « **on:** 11/06/15 15:21 »

Hi. I am trying to calculate the calcite and hydroxide precipitation in ammonia solution without redox reactions.
After calculation, I got methan, hydrogen and nitrogen generation in the result.
Do I have mistakes on the input file?

input

SOLUTION 1
    pH    7.0    charge
   temp   25.0
   unit mmol/l
   -water    1   #kg
      N(-3)   100   #as NH4
      C(4)   500   #as CO3-2
      Ca   500
      Cl   120
      Na   150

EQUILIBRIUM_PHASES 1
   Calcite          0.0   0.0
   CalciumHydroxide   0.0   0.0

PHASES
CalciumHydroxide
   Ca(OH)2 = Ca+2 + 2OH-
   log_k -5.26

END

output
------------------
Reading data base.
------------------

   SOLUTION_MASTER_SPECIES
   SOLUTION_SPECIES
   PHASES
   EXCHANGE_MASTER_SPECIES
   EXCHANGE_SPECIES
   SURFACE_MASTER_SPECIES
   SURFACE_SPECIES
   RATES
   END
------------------------------------
Reading input data for simulation 1.
------------------------------------

   DATABASE C:\Program Files (x86)\USGS\Phreeqc Interactive 3.1.2-8538\database\phreeqc.dat
   SOLUTION 1
       pH    7.0    charge
      temp   25.0
      unit mmol/l
      water    1   #kg
         N(-3)   100   #as NH4
         C(4)   500   #as CO3-2
         Ca   500
         Cl   120
         Na   150
   EQUILIBRIUM_PHASES 1
      Calcite          0.0   0.0
      CalciumHydroxide   0.0   0.0
   PHASES
   CalciumHydroxide
      Ca(OH)2 = Ca+2 + 2OH-
      log_k -5.26
   END
-------------------------------------------
Beginning of initial solution calculations.
-------------------------------------------

Initial solution 1.

-----------------------------Solution composition------------------------------

   Elements Molality Moles

   C(4) 5.317e-01 5.317e-01
   Ca 5.317e-01 5.317e-01
   Cl 1.276e-01 1.276e-01
   N(-3) 1.063e-01 1.063e-01
   Na 1.595e-01 1.595e-01

----------------------------Description of solution----------------------------

pH = 12.205 Charge balance
pe = 4.000
Specific Conductance (ｵS/cm, 25ｰC) = 27263
Density (g/cmｳ) = 1.06394
Volume (L) = 0.99985
Activity of water = 0.983
Ionic strength = 4.344e-01
Mass of water (kg) = 1.000e+00
Total alkalinity (eq/kg) = 1.202e+00
Total CO2 (mol/kg) = 5.317e-01
Temperature (ｰC) = 25.00
Electrical balance (eq) = 2.936e-13
Percent error, 100*(Cat-|An|)/(Cat+|An|) = 0.00
Iterations = 12
Total H = 1.113645e+02
Total O = 5.713382e+01

----------------------------Distribution of species----------------------------

Log Log Log mole V
Species Molality Activity Molality Activity Gamma cmｳ/mol

OH- 2.475e-02 1.594e-02 -1.606 -1.798 -0.191 -3.04
H+ 8.117e-13 6.243e-13 -12.091 -12.205 -0.114 0.00
H2O 5.551e+01 9.829e-01 1.744 -0.007 0.000 18.07
C(4) 5.317e-01
CaCO3 4.432e-01 4.898e-01 -0.353 -0.310 0.043 -14.60
CO3-2 5.644e-02 1.354e-02 -1.248 -1.868 -0.620 -2.70
NaCO3- 3.173e-02 2.319e-02 -1.499 -1.635 -0.136 1.60
HCO3- 2.576e-04 1.803e-04 -3.589 -3.744 -0.155 26.27
CaHCO3+ 6.934e-05 4.952e-05 -4.159 -4.305 -0.146 9.93
NaHCO3 8.435e-06 9.322e-06 -5.074 -5.030 0.043 1.80
CO2 2.329e-10 2.574e-10 -9.633 -9.589 0.043 29.09
Ca 5.317e-01
CaCO3 4.432e-01 4.898e-01 -0.353 -0.310 0.043 -14.60
Ca+2 8.074e-02 2.153e-02 -1.093 -1.667 -0.574 -16.91
CaOH+ 7.698e-03 5.626e-03 -2.114 -2.250 -0.136 (0)
CaHCO3+ 6.934e-05 4.952e-05 -4.159 -4.305 -0.146 9.93
Cl 1.276e-01
Cl- 1.276e-01 8.415e-02 -0.894 -1.075 -0.181 18.65
H(0) 4.992e-36
H2 2.496e-36 2.759e-36 -35.603 -35.559 0.043 28.61
N(-3) 1.063e-01
NH3 1.061e-01 1.173e-01 -0.974 -0.931 0.043 24.42
NH4+ 2.123e-04 1.285e-04 -3.673 -3.891 -0.218 18.36
Na 1.595e-01
Na+ 1.278e-01 9.196e-02 -0.894 -1.036 -0.143 -0.69
NaCO3- 3.173e-02 2.319e-02 -1.499 -1.635 -0.136 1.60
NaHCO3 8.435e-06 9.322e-06 -5.074 -5.030 0.043 1.80
NaOH 1.326e-13 1.465e-13 -12.877 -12.834 0.043 (0)
O(0) 9.575e-22
O2 4.788e-22 5.291e-22 -21.320 -21.276 0.043 30.40

------------------------------Saturation indices-------------------------------

Phase SI** log IAP log K(298 K, 1 atm)

Aragonite 4.80 -3.54 -8.34 CaCO3
Calcite 4.94 -3.54 -8.48 CaCO3
CalciumHydroxide -0.00 -5.26 -5.26 Ca(OH)2
CO2(g) -8.13 -9.59 -1.46 CO2
H2(g) -32.46 -35.56 -3.10 H2
H2O(g) -1.51 -0.01 1.50 H2O
Halite -3.68 -2.11 1.57 NaCl
NH3(g) -2.73 -0.93 1.80 NH3
O2(g) -18.38 -21.28 -2.89 O2

**For a gas, SI = log10(fugacity). Fugacity = pressure * phi / 1 atm.
For ideal gases, phi = 1.

-----------------------------------------
Beginning of batch-reaction calculations.
-----------------------------------------

Reaction step 1.

Using solution 1.
Using pure phase assemblage 1.

-------------------------------Phase assemblage--------------------------------

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

Calcite 0.00 -8.48 -8.48 0.000e+00 5.312e-01 5.312e-01
CalciumHydroxide -1.79 -7.05 -5.26 0.000e+00 0 0.000e+00

-----------------------------Solution composition------------------------------

   Elements Molality Moles

   C 5.463e-04 5.463e-04
   Ca 5.463e-04 5.463e-04
   Cl 1.276e-01 1.276e-01
   N 1.063e-01 1.063e-01
   Na 1.595e-01 1.595e-01

----------------------------Description of solution----------------------------

pH = 12.373 Charge balance
pe = -10.495 Adjusted to redox equilibrium
Specific Conductance (ｵS/cm, 25ｰC) = 20209
Density (g/cmｳ) = 1.00294
Volume (L) = 1.00765
Activity of water = 0.993
Ionic strength = 1.611e-01
Mass of water (kg) = 1.000e+00
Total alkalinity (eq/kg) = 1.382e-01
Total CO2 (mol/kg) = 1.319e-04
Temperature (ｰC) = 25.00
Electrical balance (eq) = 3.553e-13
Percent error, 100*(Cat-|An|)/(Cat+|An|) = 0.00
Iterations = 30
Total H = 1.113645e+02
Total O = 5.554031e+01

----------------------------Distribution of species----------------------------

Log Log Log mole V
Species Molality Activity Molality Activity Gamma cmｳ/mol

OH- 3.277e-02 2.373e-02 -1.485 -1.625 -0.140 -3.58
H+ 5.252e-13 4.234e-13 -12.280 -12.373 -0.094 0.00
H2O 5.551e+01 9.927e-01 1.744 -0.003 0.000 18.07
C(-4) 4.144e-04
CH4 4.144e-04 4.301e-04 -3.383 -3.366 0.016 32.22
C(4) 1.319e-04
CO3-2 6.346e-05 2.110e-05 -4.198 -4.676 -0.478 -3.80
NaCO3- 6.286e-05 4.752e-05 -4.202 -4.323 -0.121 0.07
CaCO3 5.362e-06 5.565e-06 -5.271 -5.255 0.016 -14.60
HCO3- 2.508e-07 1.904e-07 -6.601 -6.720 -0.120 25.40
NaHCO3 1.249e-08 1.296e-08 -7.904 -7.888 0.016 1.80
CaHCO3+ 4.964e-10 3.815e-10 -9.304 -9.418 -0.114 9.86
CO2 1.760e-13 1.826e-13 -12.755 -12.738 0.016 29.09
Ca 5.463e-04
Ca+2 4.601e-04 1.570e-04 -3.337 -3.804 -0.467 -17.28
CaOH+ 8.082e-05 6.111e-05 -4.092 -4.214 -0.121 (0)
CaCO3 5.362e-06 5.565e-06 -5.271 -5.255 0.016 -14.60
CaHCO3+ 4.964e-10 3.815e-10 -9.304 -9.418 -0.114 9.86
Cl 1.276e-01
Cl- 1.276e-01 9.336e-02 -0.894 -1.030 -0.136 18.42
H(0) 2.392e-07
H2 1.196e-07 1.241e-07 -6.922 -6.906 0.016 28.61
N(-3) 1.052e-01
NH3 1.051e-01 1.091e-01 -0.978 -0.962 0.016 24.42
NH4+ 1.155e-04 8.105e-05 -3.937 -4.091 -0.154 18.22
N(0) 1.105e-03
N2 5.526e-04 5.734e-04 -3.258 -3.242 0.016 29.29
N(3) 0.000e+00
NO2- 0.000e+00 0.000e+00 -58.443 -58.590 -0.147 25.32
N(5) 0.000e+00
NO3- 0.000e+00 0.000e+00 -83.260 -83.407 -0.147 29.85
Na 1.595e-01
Na+ 1.595e-01 1.210e-01 -0.797 -0.917 -0.120 -0.99
NaCO3- 6.286e-05 4.752e-05 -4.202 -4.323 -0.121 0.07
NaHCO3 1.249e-08 1.296e-08 -7.904 -7.888 0.016 1.80
NaOH 2.767e-13 2.871e-13 -12.558 -12.542 0.016 (0)
O(0) 0.000e+00
O2 0.000e+00 0.000e+00 -78.590 -78.574 0.016 30.40

------------------------------Saturation indices-------------------------------

Phase SI** log IAP log K(298 K, 1 atm)

Aragonite -0.14 -8.48 -8.34 CaCO3
Calcite 0.00 -8.48 -8.48 CaCO3
CalciumHydroxide -1.79 -7.05 -5.26 Ca(OH)2
CH4(g) -0.52 -3.37 -2.84 CH4
CO2(g) -11.28 -12.74 -1.46 CO2
H2(g) -3.81 -6.91 -3.10 H2
H2O(g) -1.51 -0.00 1.50 H2O
Halite -3.52 -1.95 1.57 NaCl
N2(g) -0.07 -3.24 -3.18 N2
NH3(g) -2.76 -0.96 1.80 NH3
O2(g) -75.68 -78.57 -2.89 O2

**For a gas, SI = log10(fugacity). Fugacity = pressure * phi / 1 atm.
For ideal gases, phi = 1.

------------------
End of simulation.
------------------

------------------------------------
Reading input data for simulation 2.
------------------------------------

-------------------------------
End of Run after 0.031 Seconds.
-------------------------------

dlparkhurst · « **Reply #1 on:** 11/06/15 23:47 »

That's what thermodynamics says should happen. One way to look at it is that you can calculate a pe from each redox pair (C(-4)/C(4), N(-3)/N(3), N(-3)/N(0), etc). At redox equilibrium, the pes calculated from all sets of redox pairs are the same. So, to have that happen, you need to make some C(-4), N(0), etc in the calculated amounts.

Now, if you don't really want to consider N(0) and all the other redox reactions, you can use the Amm.dat database, which splits N(-3) from the rest of the nitrogen system. If you define Amm in SOUTION, its concentration will remain unchanged unless you use REACTION, KINETICS, or allow Amm(g) to escape. There will be no conversion to N species, and there will be no redox reactions.

tatsu · « **Reply #2 on:** 15/06/15 08:29 »

Thank you very much!

I just simulate titration of calcium carbonate with hydrogen chloride, so that I don't need to consider any redox reactions.
The calculation with Amm.dat works well.

Author Topic: Precipitation of calcite and calcium hydroxide with ammonia (Read 4090 times)

tatsu

Precipitation of calcite and calcium hydroxide with ammonia

dlparkhurst

Re: Precipitation of calcite and calcium hydroxide with ammonia

tatsu

Re: Precipitation of calcite and calcium hydroxide with ammonia