Table 7 PHREEQC database used in geochemical reactions (equilibrium constants are at 25 °C).
Aqueous reactions | ||
|---|---|---|
1 | \({Ca}^{2+}+{SO}_{4}^{2-}=CaS{O}_{4}(aq)\) | \(\mathrm{log}k=2.25\) |
2 | \({Mg}^{2+}+{SO}_{4}^{2-}=MgS{O}_{4}(aq)\) | \(\mathrm{log}k=2.37\) |
3 | \({HCO}_{3}^{-}={H}^{+}+{CO}_{3}^{2-}\) | \(\mathrm{log}k=-10.39\) |
4 | \({HSO}_{4}^{-}={H}^{+}+{SO}_{4}^{2-}\) | \(\mathrm{log}k=41.07\) |
5 | \({CO}_{3}^{2-}+2{H}^{+}={CO}_{2}+{H}_{2}O\) | \(\mathrm{log}k=16.67\) |
Dissolution/precipitation reactions | ||
6 | \({CaC}_{3}\left(s\right)={Ca}^{2+}+{CO}_{3}^{2-}\) | \(\mathrm{log}k=-8.48\) |
7 | \(CaMg{\left(C{O}_{3}\right)}_{2}\left(s\right)={Ca}^{2+}+{Mg}^{2+}+2{CO}_{3}^{2-}\) | \(\mathrm{log}k=-17.09\) |
8 | \(CaS{O}_{4}\left(s\right)={Ca}^{2+}+{SO}_{4}^{2-}\) | \(\mathrm{log}k=-4.58\) |
Surface complexation reactions (Green: [Ca]OH, Red: [CO3]OH, Purple: [Mg]OH) | ||
9 | \(>Ca{H}_{2}{O}^{+}=>CaOH+{H}^{+}\) | \(\mathrm{log}k=-12.8\) |
10 | \(>Ca{H}_{2}{O}^{+}+{HCO}_{3}^{-}=>CaC{O}_{3}^{-}+{H}^{+}+{H}_{2}O\) | \(\mathrm{log}k=-5.65\) |
11 | \(>Ca{H}_{2}{O}^{+}+{HCO}_{3}^{-}=>CaHC{O}_{3}^{-}+{H}_{2}O\) | \(\mathrm{log}k=1.68\) |
12 | \(>Ca{H}_{2}{O}^{+}+{SO}_{4}^{2-}=>CaS{O}_{4}^{-}+{H}_{2}O\) | \(\mathrm{log}k=3.3\) |
13 | \(>Ca{H}_{2}{O}^{+}+{A}^{-}=>Ca{H}_{2}OA\) | \(\mathrm{log}k=0.4\) |
14 | \({>CO}_{3}^{-}+{H}^{+}=>C{O}_{3}H\) | \(\mathrm{log}k=5.48\) |
15 | \({>CO}_{3}^{-}+{Ca}^{2+}=>C{O}_{3}{Ca}^{+}\) | \(\mathrm{log}k=1.74\) |
16 | \({>CO}_{3}^{-}+{Mg}^{2+}=>C{O}_{3}{Mg}^{+}\) | \(\mathrm{log}k=1.74\) |
17 | \(>C{O}_{3}{Ca}^{+}+{SO}_{4}^{2-}=>C{O}_{3}Ca{SO}_{4}^{-}\) | \(\mathrm{log}k=3.3\) |
18 | \(>{{\mathrm{CO}}_{3}\mathrm{Mg}}^{+}+\mathrm{ QUOTE }{\mathrm{SO}}_{4}^{2-}=>{\mathrm{CO}}_{3}{\mathrm{MgSO}}_{4}^{-}\) | \(\mathrm{log}k=3.3\) |
19 | \(>C{O}_{3}H+{Ca}^{2+} = >C{O}_{3}{Ca}^{+}+{H}^{+}\) | \(\mathrm{log}k=-2\) |
20 | \(>{{\mathrm{CO}}_{3}\mathrm{Mg}}^{+}+{A}^{-}=>{\mathrm{CO}}_{3}\mathrm{MgA}\) | \(\mathrm{log}k=0.4\) |
21 | \(>{{\mathrm{CO}}_{3}\mathrm{Ca}}^{+}+{A}^{-}=>{\mathrm{CO}}_{3}\mathrm{CaA}\) | \(\mathrm{log}k=0.4\) |
22 | \(>C{O}_{3}H+{Mg}^{2+} = >C{O}_{3}{Mg}^{+}+{H}^{+}\) | \(\mathrm{log}k=-1.71\) |
23 | \(>MgOH= >Mg{O}^{-}+{H}^{+}\) | \(\mathrm{log}k=-12\) |
24 | \(>MgOH+{H}^{+}= >Mg{OH}_{2}^{+}\) | \(\mathrm{log}k=10.6\) |
25 | \(>MgOH{+CO}_{3}^{2-}+{H}^{+}=>MgC{O}_{3}^{-}+{H}_{2}O\) | \(\mathrm{log}k=15.4\) |
26 | \(>MgOH{+CO}_{3}^{2-}+2{H}^{+}=>MgHC{O}_{3}+{H}_{2}O\) | \(\mathrm{log}k=23.5\) |
27 | \({Na}^{+}+\frac{1}{2}>Mg{X}_{2}\iff \frac{1}{2} {Mg}^{2+}+>NaX\) | \(\mathit{log}k=-1.125\) |
