Introduction to Geochemical Modelling - University of Bristol

Physical Chemistry of Minerals and SolutionsDM Sherman, University of Bristol2008/2009Batch Reaction Model Example (Cont.)Now we can let the solution equilibrate with K-feldsparand see what happens. We constrained the reactionso that K-mica is not allowed to precipitate out sincethat is kinetically slow..-----------------------------Phase assemblage--------------------------------Moles in assemblagePhase SI log IAP log KT Initial Final DeltaK-feldspar 0.00 2.09 2.09 1.000e+01 1.000e+01 -1.107e-04K-mica 4.20 16.90 12.70 0.000e+00 0.000e+00Kaolinite 0.00 7.44 7.43 0.000e+00 5.550e-05 5.550e-05The solution will react with K-feldspar to producekaolinite..Batch Reaction Model Example (Cont.)Solution composition after reacting with feldspar..----------------------------Distribution of species----------------------------Log Log LogSpecies Molality Activity Molality Activity GammaAlH(0)KO(0)SiOH- 2.725e-05 2.685e-05 -4.565 -4.571 -0.006H+ 3.782e-10 3.728e-10 -9.422 -9.429 -0.006H2O 5.551e+01 1.000e+00 0.000 0.000 0.0001.497e-06Al(OH)4- 1.497e-06 1.475e-06 -5.825 -5.831 -0.006Al(OH)3 2.917e-10 2.917e-10 -9.535 -9.535 0.000Al(OH)2+ 7.491e-13 7.381e-13 -12.125 -12.132 -0.006AlOH+2 3.723e-17 3.511e-17 -16.429 -16.455 -0.026Al+3 1.500e-21 1.318e-21 -20.824 -20.880 -0.0562.023e-30H2 1.012e-30 1.012e-30 -29.995 -29.995 0.0002.130e-04K+ 2.129e-04 2.098e-04 -3.672 -3.678 -0.006KOH 1.952e-09 1.952e-09 -8.710 -8.710 0.0008.147e-33O2 4.074e-33 4.074e-33 -32.390 -32.390 0.0002.875e-04H4SiO4 2.052e-04 2.052e-04 -3.688 -3.688 0.000H3SiO4- 8.235e-05 8.115e-05 -4.084 -4.091 -0.006H2SiO4-2 1.570e-08 1.481e-08 -7.804 -7.830 -0.026Page ‹#›