02 - Mineral Solubility
This example corresponds to the “Example 2.-Temperature dependence of solubility of gypsum and anhydrite” from the Phreeqc manual. It can be retrieved from the Phreeqc Website.
This example shows how to calculate the solubility and relative thermodynamic stability of two minerals, gypsum and anhydrite. First, as a function of temperature at 1 atm, and second, as a function of temperature and pressure, while comparing the calculations with experimental solubility data.
Studies
This project contains 2 Studies.
PhreeqcStudy: “study_Ex2”
This study equilibrates a pure water solution with Gypsum and Anhydrite at different temperatures
Db used: “Phreeqc_dat” database
TITLE Example 2.--Temperature dependence of solubility
of gypsum and anhydrite
SOLUTION 1 Pure water
pH 7.0
temp 25.0
EQUILIBRIUM_PHASES 1
Gypsum 0.0 1.0
Anhydrite 0.0 1.0
REACTION_TEMPERATURE 1
25.0 75.0 in 51 steps
END
/n
PhreeqcStudy: “study_Ex2b”
This study equilibrates the solution with different phases at different pressures
Db used: “Phreeqc_dat” database
TITLE Calculate gypsum/anhydrite transitions, 30-170 oC, 1-1000 atm
Data in ex2b.tsv from Blount and Dickson, 1973,
Am. Mineral. 58, 323, fig. 2.
PRINT; -reset false
SOLUTION 1
EQUILIBRIUM_PHASES
Gypsum
REACTION_TEMPERATURE
30 90 in 10
END # 1st simulation
USE solution 1
USE equilibrium_phases 1
USE reaction_temperature 1
REACTION_PRESSURE 2
493
END
USE solution 1
USE equilibrium_phases 1
USE reaction_temperature 1
REACTION_PRESSURE 3
987
END # 2nd simulation
USE solution 1
EQUILIBRIUM_PHASES 4
Anhydrite
REACTION_TEMPERATURE 4
50 170 in 10
END
USE solution 1
USE equilibrium_phases 4
USE reaction_temperature 4
USE reaction_pressure 2
END
USE solution 1
USE equilibrium_phases 4
USE reaction_temperature 4
USE reaction_pressure 3
END
/n
Plots
This project contains 2 Plots.
Plot 1: “linePlot1”
Plot 2: “linePlot2”
Tables
This project contains 1 Tables.
Table 1: named “saturation_indices_vs_temp”
Temperature (deg C) |
SI Gypsum |
SI Anhydrite |
|---|---|---|
25 |
0 |
-0.3044769271344 |
26 |
0 |
-0.2934847003382 |
27 |
0 |
-0.2825414934071 |
28 |
0 |
-0.2716467664863 |
29 |
0 |
-0.2607999871606 |
30 |
0 |
-0.2500006303293 |
31 |
0 |
-0.2392481780831 |
32 |
0 |
-0.2285421195841 |
33 |
0 |
-0.2178819509477 |
34 |
0 |
-0.2072671751269 |
35 |
0 |
-0.1966973017994 |
36 |
0 |
-0.1861718472565 |
37 |
0 |
-0.1756903342943 |
38 |
0 |
-0.1652522921075 |
39 |
0 |
-0.1548572561845 |
40 |
0 |
-0.1445047682053 |
41 |
0 |
-0.1341943759409 |
42 |
0 |
-0.1239256331552 |
43 |
0 |
-0.1136980995084 |
44 |
0 |
-0.103511340462 |
45 |
0 |
-0.09336492718657 |
46 |
0 |
-0.08325843647054 |
47 |
0 |
-0.07319145063077 |
48 |
0 |
-0.06316355742521 |
49 |
0 |
-0.05317434996689 |
50 |
0 |
-0.04322342663972 |
51 |
0 |
-0.03331039101589 |
52 |
0 |
-0.02343485177462 |
53 |
0 |
-0.01359642262259 |
54 |
0 |
-0.003794722215915 |
55 |
-0.005966792219333 |
0 |
56 |
-0.01569002689089 |
0 |
57 |
-0.02537781136478 |
0 |
58 |
-0.03503050622366 |
0 |
59 |
-0.04464846740823 |
0 |
60 |
-0.05423204629138 |
0 |
61 |
-0.06378158975073 |
0 |
62 |
-0.07329744024027 |
0 |
63 |
-0.08277993586016 |
0 |
64 |
-0.09222941042545 |
0 |
65 |
-0.1016461935337 |
0 |
66 |
-0.1110306106311 |
0 |
67 |
-0.1203829830772 |
0 |
68 |
-0.1297036282092 |
0 |
69 |
-0.1389928594038 |
0 |
70 |
-0.1482509861393 |
0 |
71 |
-0.1574783140556 |
0 |
72 |
-0.1666751450132 |
0 |
73 |
-0.1758417771516 |
0 |
74 |
-0.1849785049463 |
0 |
75 |
-0.1940856192643 |
0 |