Table 4 Predicted equilibrium pH and nitrogen speciation in the N-H2O-Fe-Ni system (only species with molalities above 1·10-8 shown). Concentrations and fugacities of dominant N species are in bold. The last column shows the predicted final mineral assemblage.
Mineral | T [°C] | pH | mNH 3 | mNH 4 + | mN 2 | mH 2 | fNH 3 | fN 2 | fH 2 | Assemblage |
|---|---|---|---|---|---|---|---|---|---|---|
Nickel | 200 | 6.95 | 6.4·10 -4 | 4.63·10-5 | 2.47·10-4 | 3.73·10-5 | 1.24·10-3 | 0.2769 | 0.24 | BN, NI |
Nickel | 70 | 8.92 | 1.00·10 -3 | 1.34·10-4 | 2.2·10-5 | 2.68·10-7 | 9.98·10-5 | 0.0477 | 3.68·10-4 | BN, NI |
Nickel | 22 | 10.2 | 1.03·10 -3 | 1.34·10-4 | 8.12·10-6 | 2.18·10-8 | 1.41·10-5 | 0.0118 | 2.71·10-5 | BN, NI |
Awaruite | 200 | 7.07 | 1.12·10 -3 | 6.14·10-5 | <1·10-8 | 0.0597 | 2.16·10 -3 | <1·10-8 | 38.54 | AW, MT, NI |
Awaruite | 70 | 8.93 | 1.04·10 -3 | 1.37·10-4 | <1·10-8 | 0.0152 | 1.04·10 -4 | <1·10-8 | 20.85 | AW, MT, NI |
Awaruite | 22 | 10.2 | 1.05·10 -3 | 1.35·10-4 | <1·10-8 | 0.0103 | 1.44·10 -5 | <1·10-8 | 12.82 | AW, MT, NI |
Tetrataenite | 200 | 8.7 | 5.92·10 -4 | 7.96·10-7 | <1·10-8 | 0.0865 | 1.14·10 -3 | <1·10-8 | 55.85 | AW, MT, TT |
Tetrataenite | 70 | 8.93 | 1.04·10 -3 | 1.37·10-4 | <1·10-8 | 0.0222 | 1.04·10 -4 | <1·10-8 | 30.51 | AW, MT, TT |
Tetrataenite | 22 | 10.2 | 1.05·10 -3 | 1.35·10-4 | <1·10-8 | 0.0159 | 1.44·10 -5 | <1·10-8 | 19.73 | AW, MT, TT |
Iron | 200 | 7.07 | 1.15·10 -3 | 6.22·10-5 | <1·10-8 | 1.532 | 2.22·10 -3 | <1·10-8 | 989.1 | MT, FE |
Iron | 70 | 8.93 | 1.06·10 -3 | 1.38·10-4 | <1·10-8 | 0.785 | 1.05·10 -4 | <1·10-8 | 1077 | MT, FE |
Iron | 22 | 10.2 | 1.06·10 -3 | 1.36·10-4 | <1·10-8 | 0.623 | 1.45·10 -5 | <1·10-8 | 771.5 | MT, FE |
Goethite | 200 | 5.59 | <1·10-8 | <1·10-8 | 5.86·10 -4 | <1·10-8 | <1·10-8 | 0.6574 | <1·10-8 | HM |
Goethite | 70 | 6.1 | <1·10-8 | <1·10-8 | 5.86·10 -4 | <1·10-8 | <1·10-8 | 1.273 | <1·10-8 | HM |
Goethite | 22 | 6.22 | <1·10-8 | <1·10-8 | 5.86·10 -4 | <1·10-8 | <1·10-8 | 0.8475 | <1·10-8 | HM |
Magnetite | 200 | 6.08 | 1.04·10-5 | 5.42·10-6 | 5.82·10 -4 | 1.79·10-6 | 2.0·10-5 | 0.653 | 1.16·10-3 | HM, MT |
Magnetite | 70 | 8.47 | 1.26·10-4 | 4.73·10-5 | 5.04·10 -4 | 2.36·10-8 | 1.25·10-5 | 1.094 | 3.24·10-5 | HM, MT |
Magnetite | 22 | 9.97 | 3.1·10-4 | 7.35·10-5 | 3.98·10 -4 | <1·10-8 | 4.26·10-6 | 0.5759 | 3.32·10-6 | HM, MT |
Ferrihydrite | 200 | 5.59 | <1·10-8 | <1·10-8 | 5.81·10 -4 | <1·10-8 | <1·10-8 | 0.6512 | <1·10-8 | HM |
Ferrihydrite | 70 | 6.1 | <1·10-8 | <1·10-8 | 5.81·10 -4 | <1·10-8 | <1·10-8 | 1.261 | <1·10-8 | HM |
Ferrihydrite | 22 | 6.22 | <1·10-8 | <1·10-8 | 5.81·10 -4 | <1·10-8 | <1·10-8 | 0.8396 | <1·10-8 | HM |