kineticsSi.ppi
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# plot of the dissolution of quartz vs time based on the PHREEQC kinetics model
SPECIATION
calculationType custom
calculationMethod 1
selectedOutputLines auto
PLOT
plotTitle "Kinetics of quartz dissolution<br>(from Appelo 'Get-going' sheet 11)"
xtitle "Time (year)"
ytitle "Si (mmol/kgw)"
customXColumn time # plot x = time
lines Si # plot y(line) = Si
linecolor blue
linewidth 0.6
labelSize 0 # suppresses label
legendTextSize 0 # suppresses key
numericTags <log_k> = -13.7
extraText extratextkinetics.dat # additional text (including some Greek symbols)
CHEMISTRY
# Kinetics of quartz dissolution
# from Appelo 'Get-going sheet #11'
RATES
#1 dQu/dt = -k * (1 - SR(Quartz). k = 10^-13.7 mol/m2/s (25 C)
#2 parm(1) = A (m2), parm(2) = V (dm3) recalculate to mol/dm3/s
Quartz # rate name
-start
10 moles = parm(1) / parm(2) * (m/m0)^0.67 * 10^<log_k> * (1 - SR("Quartz"))
20 save moles * time # integrate. save and time must be in rate definition
-end # moles count positive when added to solution
KINETICS # Sediment: 100% qu, grain size 0.1 mm, por 0.3, rho_qu 2.65 kg/dm3
Quartz # rate name
-formula SiO2
-m0 102.7 # initial moles of quartz
-parms 22.7 0.162 # parameters for rate eqn. Here:
# Quartz surface area (m2/kg sediment), water filled porosity (dm3/kg sediment)
-step 1.5768e8 in 100 steps # 1.5768e8 seconds = 5 years
-tol 1e-8 # integration tolerance, default 1e-8 mol
INCREMENTAL_REACTIONS true # start integration from previous step
SOLUTION 1
SELECTED_OUTPUT
-reset FALSE
USER_PUNCH
-heading time Si SIQtz # these are accumulated in the out file ready for plotting
-start
10 IF (step_no>0) THEN punch total_time/3.1536e7, tot("Si")*1e3, SI("Quartz")
-end
END
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