06 - Reaction Path Calculations
This example corresponds to the “Example 6-Reaction-Path Calculations” from the Phreeqc manual. It can be retrieved from the Phreeqc Website.
In this example, the precipitation of phases as a result of incongruent dissolution of K-feldspar (microcline) is investigated. Only the four phases originally addressed by Helgeson and others (1969)–K-feldspar, gibbsite, kaolinite, and K-mica (muscovite)–are considered.
Studies
This project contains 1 Studies.
PhreeqcStudy: “study_06 - Reaction Path Calculations”
Db used: “Phreeqc_dat” database
TITLE Simulation 6A.--React to phase boundaries.
SOLUTION 1 PURE WATER
pH 7.0 charge
temp 25.0
PHASES
Gibbsite
Al(OH)3 + 3 H+ = Al+3 + 3 H2O
log_k 8.049
delta_h -22.792 kcal
Kaolinite
Al2Si2O5(OH)4 + 6 H+ = H2O + 2 H4SiO4 + 2 Al+3
log_k 5.708
delta_h -35.306 kcal
K-mica
KAl3Si3O10(OH)2 + 10 H+ = 3 Al+3 + 3 H4SiO4 + K+
log_k 12.970
delta_h -59.377 kcal
K-feldspar
KAlSi3O8 + 4 H2O + 4 H+ = Al+3 + 3 H4SiO4 + K+
log_k 0.875
delta_h -12.467 kcal
END
TITLE Simulation 6A1.--Find amount of K-feldspar dissolved to
reach gibbsite saturation.
USE solution 1
EQUILIBRIUM_PHASES 1
Gibbsite 0.0 KAlSi3O8 10.0
Kaolinite 0.0 0.0
K-mica 0.0 0.0
K-feldspar 0.0 0.0
END
TITLE Simulation 6A2.--Find amount of K-feldspar dissolved to
reach kaolinite saturation.
USE solution 1
EQUILIBRIUM_PHASES 1
Gibbsite 0.0 0.0
Kaolinite 0.0 KAlSi3O8 10.0
K-mica 0.0 0.0
K-feldspar 0.0 0.0
END
TITLE Simulation 6A3.--Find amount of K-feldspar dissolved to
reach K-mica saturation.
USE solution 1
EQUILIBRIUM_PHASES 1
Gibbsite 0.0 0.0
Kaolinite 0.0 0.0
K-mica 0.0 KAlSi3O8 10.0
K-feldspar 0.0 0.0
END
TITLE Simulation 6A4.--Find amount of K-feldspar dissolved to
reach K-feldspar saturation.
USE solution 1
EQUILIBRIUM_PHASES 1
Gibbsite 0.0 0.0
Kaolinite 0.0 0.0
K-mica 0.0 0.0
K-feldspar 0.0 KAlSi3O8 10.0
END
TITLE Simulation 6A5.--Find point with kaolinite present,
but no gibbsite.
USE solution 1
EQUILIBRIUM_PHASES 1
Gibbsite 0.0 KAlSi3O8 10.0
Kaolinite 0.0 1.0
END
TITLE Simulation 6A6.--Find point with K-mica present,
but no kaolinite
USE solution 1
EQUILIBRIUM_PHASES 1
Kaolinite 0.0 KAlSi3O8 10.0
K-mica 0.0 1.0
END
TITLE Simulation 6B.--Path between phase boundaries.
USE solution 1
EQUILIBRIUM_PHASES 1
Kaolinite 0.0 0.0
Gibbsite 0.0 0.0
K-mica 0.0 0.0
K-feldspar 0.0 0.0
REACTION 1
K-feldspar 1.0
0.04 0.08 0.16 0.32 0.64 1.0 2.0 4.0
8.0 16.0 32.0 64.0 100 200 umol
END
TITLE Simulation 6C.--kinetic calculation
SOLUTION 1
-units mol/kgw
Al 1.e-13
K 1.e-13
Si 3.e-13
EQUILIBRIUM_PHASES 1
Gibbsite 0.0 0.0
Kaolinite 0.0 0.0
K-mica 0.0 0.0
KINETICS 1
K-feldspar
# k0 * A/V = 1e-16 mol/cm2/s * (10% fsp, 0.1mm cubes) 136/cm = 136.e-13 mol/dm3/s
-parms 1.36e-11
-m0 2.16
-m 1.94
-step_divide 1e-6
-steps 1e2 1e3 1e4 1e5 1e6 1e7 1e8
# -steps 1e2 1e3 1e4 1e5 63240.0 64950.0 1347610.0 1010300.0 45242800.0
INCREMENTAL_REACTIONS true
RATES
K-feldspar
-start
10 REM store the initial amount of K-feldspar
20 IF EXISTS(1) = 0 THEN PUT(M, 1)
30 REM calculate moles of reaction
40 SR_kfld = SR("K-feldspar")
50 moles = PARM(1) * (M/M0)^0.67 * (1 - SR_kfld) * TIME
60 REM The following is for printout of phase transitions
80 REM Start Gibbsite
90 if ABS(SI("Gibbsite")) > 1e-3 THEN GOTO 150
100 i = 2
110 GOSUB 1500
150 REM Start Gibbsite -> Kaolinite
160 if ABS(SI("Kaolinite")) > 1e-3 THEN GOTO 200
170 i = 3
180 GOSUB 1500
200 REM End Gibbsite -> Kaolinite
210 if ABS(SI("Kaolinite")) > 1e-3 OR EQUI("Gibbsite") > 0 THEN GOTO 250
220 i = 4
230 GOSUB 1500
250 REM Start Kaolinite -> K-mica
260 if ABS(SI("K-mica")) > 1e-3 THEN GOTO 300
270 i = 5
280 GOSUB 1500
300 REM End Kaolinite -> K-mica
310 if ABS(SI("K-mica")) > 1e-3 OR EQUI("Kaolinite") > 0 THEN GOTO 350
320 i = 6
330 GOSUB 1500
350 REM Start K-mica -> K-feldspar
360 if ABS(SI("K-feldspar")) > 1e-3 THEN GOTO 1000
370 i = 7
380 GOSUB 1500
1000 SAVE moles
1010 END
1500 REM subroutine to store data
1510 if GET(i) >= M THEN RETURN
1520 PUT(M, i)
1530 PUT(TOTAL_TIME, i, 1)
1540 PUT(LA("K+")-LA("H+"), i, 2)
1550 PUT(LA("H4SiO4"), i, 3)
1560 RETURN
-end
USER_PRINT
10 DATA "A: Gibbsite ", "B: Gibbsite -> Kaolinite ", \
"C: Gibbsite -> Kaolinite ", "D: Kaolinite -> K-mica ", \
"E: Kaolinite -> K-mica ", "F: K-mica -> K-feldspar"
20 PRINT \
" Transition Time K-feldspar LA(K/H) LA(H4SiO4)"
30 PRINT " transfer"
40 PRINT " (umoles)"
50 FOR i = 2 TO 7
60 READ s$
70 IF EXISTS(i) THEN PRINT s$, GET(i,1), (GET(1) - GET(i))*1e6, GET(i,2), GET(i,3)
80 NEXT i
END
PRINT; -user_print false
# --Plot the phase boundaries with USER_GRAPH..
PHASES
K_H; KH = K+ - H+; -no_check
SOLUTION 1
pH 11; K 1 K_H 8; Al 1 Gibbsite; Si 1 K-mica
SOLUTION 2
pH 7; K 1 K-mica; Al 1 Gibbsite; Si 1 Kaolinite
SOLUTION 3
pH 7; K 1 K-mica; Al 1 K-feldspar; Si 1 Kaolinite
SOLUTION 4
pH 7; K 1 K_H -1; Al 1 Kaolinite; Si 1 K-feldspar
END
SOLUTION 1
pH 11; K 1 K_H 8; Al 1 K-feldspar; Si 1 K-mica
SOLUTION 2
pH 7; K 1 K-mica; Al 1 K-feldspar; Si 1 Kaolinite
SOLUTION 3
pH 7; K 1 K-mica; Al 1 Gibbsite; Si 1 Kaolinite
SOLUTION 4
pH 7; K 1 K_H -1; Al 1 Gibbsite; Si 1 Kaolinite
END
/n
Plots
This project contains 1 Plots.
Plot 1: “linePlot1”
