Pyrite oxidation/dissolution process

[gmgmgm]

Dear all,
 I have a question about Pyrite oxidation/dissolution process，in  phreeqc.dat ，there is only one reaction regarding pyrite

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Pyrite
FeS2 + 2 H+ + 2 e- = Fe+2 + 2 HS-
-log_k -18.479
-delta_h 11.300 kcal
-Vm 23.48
But we all konw that the really reaction should be

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2FeS2 + 7O2 + 2H2O=2Fe + 4SO4 +4H.
And how should I rewrite it?  The log_k of the new reaction?
Thank you all!!

[dlparkhurst]

What if NO3- is the oxidant, or Fe+3?

In fact it does not matter how the pyrite oxidation reaction is written (provided you have the correct log K). All of the aqueous reactions are in equilibrium, so you could add O2 + 4e- + 2H2O = 4OH- with the the appropriate log K to get a new pyrite dissolution reaction with O2, but the results for a pyrite equilibrium calculation would be the same.