01 - Speciation calculation
This example corresponds to the “Example 1-Speciation Calculation” from the Phreeqc manual. It can be retrieved from the Phreeqc Website.
This example calculates the distribution of aqueous species in seawater and the saturation state of seawater relative to a set of minerals.
Studies
This project contains 1 Studies.
PhreeqcStudy: “PhreeqcStudy”
Note that in this study new species and phases are added in the database
Db used: “Phreeqc_dat” database
TITLE Example 1.--Add uranium and speciate seawater.
SOLUTION 1 SEAWATER FROM NORDSTROM AND OTHERS (1979)
units ppm
pH 8.22
pe 8.451
density 1.023
temp 25.0
redox O(0)/O(-2)
Ca 412.3
Mg 1291.8
Na 10768.0
K 399.1
Fe 0.002
Mn 0.0002 pe
Si 4.28
Cl 19353.0
Alkalinity 141.682 as HCO3
S(6) 2712.0
N(5) 0.29 gfw 62.0
N(-3) 0.03 as NH4
U 3.3 ppb N(5)/N(-3)
O(0) 1.0 O2(g) -0.7
SOLUTION_MASTER_SPECIES
U U+4 0.0 238.0290 238.0290
U(4) U+4 0.0 238.0290
U(5) UO2+ 0.0 238.0290
U(6) UO2+2 0.0 238.0290
SOLUTION_SPECIES
#primary master species for U
#is also secondary master species for U(4)
U+4 = U+4
log_k 0.0
U+4 + 4 H2O = U(OH)4 + 4 H+
log_k -8.538
delta_h 24.760 kcal
U+4 + 5 H2O = U(OH)5- + 5 H+
log_k -13.147
delta_h 27.580 kcal
#secondary master species for U(5)
U+4 + 2 H2O = UO2+ + 4 H+ + e-
log_k -6.432
delta_h 31.130 kcal
#secondary master species for U(6)
U+4 + 2 H2O = UO2+2 + 4 H+ + 2 e-
log_k -9.217
delta_h 34.430 kcal
UO2+2 + H2O = UO2OH+ + H+
log_k -5.782
delta_h 11.015 kcal
2UO2+2 + 2H2O = (UO2)2(OH)2+2 + 2H+
log_k -5.626
delta_h -36.04 kcal
3UO2+2 + 5H2O = (UO2)3(OH)5+ + 5H+
log_k -15.641
delta_h -44.27 kcal
UO2+2 + CO3-2 = UO2CO3
log_k 10.064
delta_h 0.84 kcal
UO2+2 + 2CO3-2 = UO2(CO3)2-2
log_k 16.977
delta_h 3.48 kcal
UO2+2 + 3CO3-2 = UO2(CO3)3-4
log_k 21.397
delta_h -8.78 kcal
PHASES
Uraninite
UO2 + 4 H+ = U+4 + 2 H2O
log_k -3.490
delta_h -18.630 kcal
END
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