TITLE Albite dissolution kinetics with Burch equation and parameter SOLUTION_SPECIES 1.0000 H2O = OH- +1.0000 H+ log_k -13.995 1.0000 H2O + 1.0000 Al+++ = AlOH++ +1.0000 H+ log_k -4.965 2.0000 H2O + 1.0000 Al+++ = Al(OH)2+ +2.0000 H+ log_k -10.921 2.0000 H2O + 1.0000 Al+++ = HAlO2 +3.0000 H+ log_k -16.262 2.0000 H2O + 1.0000 Al+++ = AlO2- +4.0000 H+ log_k -22.864 2.0000 H2O + 1.0000 Na+ + 1.0000 Al+++ = NaAlO2 +4.0000 H+ log_k -23.602 1.0000 Al+++ + 1.0000 SiO2 + 2.0000 H2O = AlH3SiO4++ + 1.0000 H+ log_k -2.613 1.0000 Na+ + 1.0000 H2O = NaOH +1.0000 H+ log_k -14.205 1.0000 SiO2 + 1.0000 H2O = HSiO3- +1.0000 H+ log_k -9.842 1.0000 SiO2 + 1.0000 Na+ + 1.0000 H2O = NaHSiO3 +1.0000 H+ log_k -8.011 PHASES Albite NaAlSi3O8 +4.0000 H+ = + 1.0000 Al+++ + 1.0000 Na+ + 2.0000 H2O + 3.0000 SiO2 log_k 2.848 Paragonite NaAl3Si3O10(OH)2 +10.0000 H+ = + 1.0000 Na+ + 3.0000 Al+++ + 3.0000 SiO2 + 6.0000 H2O log_k 15.755 Quartz SiO2 = + 1.0000 SiO2 log_k -3.75 Kaolinite Al2Si2O5(OH)4 +6.0000 H+ = + 2.0000 Al+++ + 2.0000 SiO2 + 5.0000 H2O log_k 5.09 Gibbsite Al(OH)3 +3.0000 H+ = + 1.0000 Al+++ + 3.0000 H2O log_k 7.73 SOLUTION 1 temp 25 units mol/kgw ph 6 Ca 0.05 Cl 3 charge C(4) 0.02 Al 1e-7 EQUILIBRIUM_PHASES 1 kaolinite 0 0 PARAGONITE 0.0 0 kinetics 1 define Albite parameters Albite -m 1 -m0 1 -parms 0.2 1 -steps 631138500000 in 300 steps INCREMENTAL_REACTIONS TRUE RATES ########### #Albite ########### Albite -start 1 rem unit should be mol,Liter-1 and second-1 2 rem parm(1) is surface area in the unit of m2/L 3 rem calculation of surface area can be found in the note 4 rem M is current moles of minerals,M0 is the initial moles of minerals 5 rem parm(2) is a correction factor for fields rate relative to lab rate 6 rem rate here is the product of Palandri's far from equilibrium rate and the f(DGr) term from Burch 1993 10 rem acid solution parameters 11 a1=1.45E+0 12 E1=58400 13 n1=0.335 20 rem neutral solution parameters 21 a2=4.97E-10 22 E2=57000 30 rem base solution parameters 31 a3=3.00e-5 32 E3=55500 33 n2=-0.317 36 rem rate=0 if no minerals and undersaturated 41 if (M<0) then goto 200 42 if (M=0 and SR_mineral<1) then goto 200 50 SA=parm(1)* (M/M0)^0.67 60 R=8.31451 75 Rate1=a1*EXP(-E1/R/TK)*ACT("H+")^n1 #acide rate expression 80 Rate2=a2*EXP(-E2/R/TK) #neutral rate expression 85 Rate3=a3*EXP(-E3/R/TK)*ACT("H+")^n2 #base rate expression 90 Rate0=(Rate1+Rate2+Rate3)*SA*parm(2) 95 XX=(Rate1+Rate2+Rate3) 98 PUT(XX,2) 100 rem f(DGr) term in Burch 1993 110 SI_mineral=SI("Albite") 120 F1=0.917746*(1-exp(-8.4E-17*(ABS(2.303*SI_mineral))^15)) 130 F2=0.082254*(1-exp(-ABS(-2.303*SI_mineral)))^1.45 140 F=F1+F2 150 Rate=Rate0*F 160 PUT(Rate,1) 180 moles= rate*Time 190 rem do not dissolve more minerals than present 195 if (moles>M) then moles=M 200 save moles -end SELECTED_OUTPUT -file Burch.txt -reset false USER_PUNCH -headings Time(year) rate a_Na+ SI(Albite) pH a_SiO2 a_Al+3 XX -start 10 punch TOTAL_TIME/31556925 GET(1) 10^(LA("Na+")) SI("Albite") LA("H+") 10^LA("SiO2") TOT("Al") GET(2) -end END