TITLE Example 5.--Add oxygen, equilibrate with pyrite, calcite, and goethite.
SOLUTION 1  PURE WATER
        pH      7.0
        temp    25.0
EQUILIBRIUM_PHASES 1
        Pyrite          0.0
        Goethite        0.0
        Calcite         0.0
        CO2(g)         -3.5
        Gypsum          0.0     0.0
REACTION 1
        O2      1.0
        NaCl    0.5
        0.0     0.001   0.005   0.01   0.03   0.05
SELECTED_OUTPUT
        -file   ex5.sel
        -total  Cl
        -si     Gypsum
        -equilibrium_phases  pyrite goethite calcite CO2(g) gypsum
USER_GRAPH Example 5
        -headings Pyrite Goethite Calcite CO2(g) Gypsum SI_Gypsum
        -chart_title "Pyrite Oxidation"
        -axis_titles "O2 added, in millimoles" "Millimoles dissolved" \
             "Saturation index"
  10 x = RXN * 1e3
  20 PLOT_XY x, 1e3 * (10 - EQUI("Pyrite")), symbol = Plus
  30 PLOT_XY x, 1e3 * (10 - EQUI("Goethite")), symbol = Plus
  40 PLOT_XY x, 1e3 * (10 - EQUI("Calcite")), symbol = Plus
  50 PLOT_XY x, 1e3 * (10 - EQUI("CO2(g)")), symbol = Plus
  60 PLOT_XY x, 1e3 * (-EQUI("Gypsum")), symbol = Plus, color = Magenta
  70 PLOT_XY x, SI("Gypsum"), y-axis = 2, line_width = 2, symbol = Circle, \
  	symbol_size = 8, color = Magenta
END