TITLE Albite dissolution kinetics
SOLUTION 1
        temp        25
        units       mol/kgw
        ph          6
        Na          0.3
        Ca          0.05
        Cl        . 3        charge
        C(4)        0.02
EQUILIBRIUM_PHASES 1
        Quartz           0.0
        Kaolinite        0.0
        Muscovite        0.0
KINETICS 1 Define Albite parameters
        Albite
                -m            0.03814  # 10 grams albite
                -m0           0.03814
                -parms        18370  117200
        -steps        6311385e4 in 100 steps
INCREMENTAL_REACTIONS true
RATES
        Albite
        -start
        1        rem M = current no. moles of Ab
        2        rem at start, M (= m) = M0 = .03814
        3        rem Initial area (A0) is 1000 [cm^2/g] for 10 g (=1e4 cm^2)
        4        rem so A0/V [cm^-1] is 10
        5        rem pre-exp const A [mol/cm^2.s] is 18370 = PARM(1)
        6        rem act energy Ea [J/mol] is 117200 = PARM(2)
        7        rem this gives rate const of 5.50e-17 mol/[cm^2.s] at 25C
        10        A0 = 1e4
        15        V = 1000
        20        sr_ab = SR("Albite")
        25        if (M <= 0) then goto 200
        30        R = 8.31451
        35        T = 298.15
        45        area = (M/M0)^(2/3)*A0
        50        rate_const = PARM(1)*EXP(-PARM(2)/(R*T))
        55        rate = (area/V)*rate_const*(1-sr_ab)
        60        rem multiply by 1000 to change mol/(cm^3.s) to mol/(L.s)
        65        rate = rate*1000
        70        moles = rate*TIME
        75        PUT(area,1)
        80        PUT(rate,2)
        200        SAVE moles
        -end
SELECTED_OUTPUT
        -file     albite.sel
        -reset    false
USER_PUNCH
        -headings  Ab_left  area  rate  Time(years)  a_Na+  SI(Albite)
        -start
        10  PUNCH  M  GET(1) GET(2) TOTAL_TIME/31556925 10^(LA("Na+")) SI("Albite")
        -end
END