Geofluids / 2018 / Article / Tab 2

Research Article

Physiochemical Restrictions of Mineral Zoning of Sediment-Hosted Stratiform Copper Deposit in SW China

Table 2

Chemical reactions and Eh-pH expressions.

Chemical reactionspH-Eh expressions
523 K473 K423 K373 K

(1) 2H2O = O2 + 4H+ + 4e1.129 − 0.104pH1.142 − 0.094pH1.166 − 0.084pH1.167 − 0.074pH
(2) H2 = 2H+ + 2e−0.104pH−0.094pH−0.084pH−0.074pH
(3) = + H+pH = 5.40pH = 4.56pH = 3.73pH = 2.98
(4) S + 4H2O = + 7H+ + 6e0.367 − 0.121pH0.340 − 0.110pH0.33 − 0.098pH0.288 − 0.086pH
(5) S + 4H2O = + 8H+ + 6e0.462 − 0.138pH0.411 − 0.125pH0.38 − 0.112pH0.325 − 0.099pH
(6) H2S = S + 2H+ + 2e0.233 − 0.104pH0.220 − 0.094pH0.211 − 0.084pH0.205 − 0.074pH
(7) H2S = HS + H+pH = 7.61pH = 7.09pH = 6.71pH = 6.57
(8) HS + 4H2O = + 9H+ + 8e0.305 − 0.117pH0.280 − 0.106pH0.268 − 0.094pH0.235 − 0.083pH
(9) HS = S2− + H+pH = 11.43pH = 11.28pH = 11.30pH = 11.68
(10) S2− + 4H2O = + 8H+ + 8e0.157 − 0.104pH0.148 − 0.094pH0.149 − 0.084pH0.127 − 0.074pH
(11) 3Fe + 4H2O = Fe3O4 + 8H+ + 8e−0.085 − 0.104pH−0.903 − 0.094pH−0.091 − 0.084pH−0.112 − 0.074pH
(12) 2Fe3O4 + H2O = 3Fe2O3 + 2H+ + 2e0.24 − 0.104pH0.22 − 0.094pH0.21 − 0.084pH0.17 − 0.074pH
(13) Fe2+ = Fe3+ + e0.950.940.900.86
(14) 2Fe2+ + 3H2O = Fe2O3 + 6H+ + 2e1.602 − 0.341pH1.352 − 0.282pH1.282 − 0.252pH1.142 − 0.222pH
(15) 3Fe2+ + 4H2O = Fe3O4 + 8H+ + 2e2.258 − 0.456pH1.918 − 0.376pH1.818 − 0.336pH1.628 − 0.296pH
(16) 2Fe3+ + 3H2O = Fe2O3 + 6H+pH = 1.18pH = 1.11pH = 1.34pH = 1.3
(17) 2Cu + 4H2O = Cu2O + 2H+ + 2e0.46 − 0.104pH0.45 − 0.094pH0.46 − 0.084pH0.44 − 0.074pH
(18) Cu2O + H2O = 2CuO + 2H+ + 2e0.67 − 0.104pH0.65 − 0.094pH0.62 − 0.084pH0.62 − 0.074pH
(19) Cu+ = Cu2+ + e0.370.320.270.22
(20) Cu+ + e = Cu−0.30−0.36−0.41−0.45
(21) 2Cu+ + H2O = Cu2O + 2H+pH = 9.53pH = 9.05pH = 8.65pH = 7.86
(22) Cu2+ + H2O = CuO + 2H+pH = 6.23pH = 6.32pH = 6.58pH = 6.60
(23) 2Cu2+ + H2O = Cu2O + 2H+ + 2e0.622 − 0.104pH0.532 − 0.094pH0.462 − 0.084pH0.362 − 0.074pH
(24) Fe2+ + 2H2S = FeS2 + 4H+ + 2e
(25) Fe2+ + S2 + 2e = FeS2
(26) Cu+ + = Cu2+ + + e−0.63−0.67−0.72−0.77
(27) 2FeS2 + Cu2+ + 4H+ + 4e = CuFeS2 + Fe2+ + 2H2S−0.16 + 0.104pH−0.15 + 0.094pH−0.14 + 0.084pH−0.14 + 0.074pH
(28) 2CuFeS2 + 3Cu2+ = Cu5FeS4 + Fe2+ + 4e−0.59−0.59−0.59−0.6
(29) 2Cu+ + S2− = Cu2S
(30) 15Cu2S + 2Fe3O4 + 7H+ + 9HS = 6Cu5FeS4 + 8H2O + 2e−4.86 + 0.364pH−4.34 + 0.329pH−3.96 + 0.294pH−2.1 + 0.259pH

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