Hydrochemistry based on REE Data - Some Thoughts & Examples
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Transcript of Hydrochemistry based on REE Data - Some Thoughts & Examples
Thermodynamics Workshop 18-19 Jan 2016School of Earth and Environment, University of Leeds
Hydrochemistrybased on REE Data
Harald Kalka UIT GmbH Dresden
1
Software2
Data3
Theory(since 101 years)
(since 102 years)
now
Two Principal Approaches
LMALaw of Mass Action
GEMGibbs Energy Minimization
log K + mass balance
G → min + mass balance
PhreeqC EQ3/6 Minteq
ChemSage Fact GEMS-PSI
4
LMA – Law of Mass Action
aA + bB = cC + dD log K
beq
aeq
deq
ceq
}B{}A{}D{}C{
K
RT303.2GKlog
0ion activity
5
Two Types of Problems
non-ideal solutions (I > 0)
complete & consistent thermodynamic datasets (log K’s)
the Achilles’ heel of any hydrochem modeling
6
Non-Ideal Solutions
Activities are introduced in order to preserve the ideal gas equationsin a non-ideal world of real solutions.
pV = nRT
{i} = γ [i]∙
7
LMA – Main Idea
mole balance
N
1ji
i,j}j{K}i{
SN
1ii,jTOT ]i[]j[
mass action
N master species
NS species
concentration
activity
Note the Asymmetry !
LMA – Numerical Solver
8
0}k{K]j[)c,..,c,c(fS
i,k
N
1i
N
1ki
i
i,jTOTN21j
f(x) = 0Newton-Raphson
N
1
1
c
cc
x
Model & Software Development
10
C++ Classes
species, stoichiometry,log K values ...
space
time
KiLea
0 1 2 3
0
1
aquaC
lakes TRN
Flooding
Ron
petro
FEFLOW
seism
rivNETpCHM
kinetics
transport
thermodynamics
aquaC – Virtual Water Lab
13
aquaC – Virtual Water Lab
solid phases of Eu and Gd
REE &NORM
REE Data
aqueous speciesllnl.dat EQ3/6
yespure solids (yes)ion exchange nosolid solutions no
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Atomic and Effective Ionic Radii
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
atomRE+2RE+3RE+4
Sc Y La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Radius in nm
[Ullmann 2012]
EuYb
atom
REE+3
16
REE Speciation
pH 7.0pe 4
Y 1e-5La 1e-5Ce 1e-5Pr 1e-5Nd 1e-5Sm 1e-5Eu 1e-5Gd 1e-5Tb 1e-5Dy 1e-5Ho 1e-5Er 1e-5Tm 1e-5Yb 1e-5Lu 1e-5
C(4) 3e-5Cl 6e-5P 6e-5F 6e-5S(6) 6e-5
synthetic input solution
cations: 15 REEs(total 0.45 meq/L)
anions(total 0.45 meq/L)
Eu
Gd
additional
Titration Calculations
Aqueous Speciation
Titration Calculations
Eu
Gd
additional
Mole Balance
Resume (Problems with REE Data)
SO4-2 + Ce+3 = CeSO4+ logK -3.687 3.687
Typos (wrong sign, etc.)
SO4-2 + Pr+3 = PrSO4+ logK -3.687 3.687
Incompleteness# species Eu > other REE
HPO4-2 + Gd+3 = GdHPO4+ logK -185.109 5.75 (?)
Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb LuR(CO3)2- WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 HCO3- + R+3 = R(CO3)2- + 2 H+
R(CO3)3-3 ##### ##### ##### ##### ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### 3 HCO3- + R+3 = R(CO3)3-3 + 3 H+
R(HPO4)2- WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 HPO4-2 + R+3 = R(HPO4)2-
R(OH)2+ WAHR ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### 2 H2O + R+3 = R(OH)2+ + 2 H+
R(OH)2CO3- ##### ##### ##### ##### ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### 2 H2O + HCO3- + R+3 = R(OH)2CO3- + 3 H+
R(OH)3 WAHR ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### 3 H2O + R+3 = R(OH)3 + 3 H+
R(OH)4- WAHR ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### 4 H2O + R+3 = R(OH)4- + 4 H+
R(PO4)2-3 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 HPO4-2 + R+3 = R(PO4)2-3 + 2 H+
R(SO4)2- WAHR WAHR ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 SO4-2 + R+3 = R(SO4)2-
R+2 ##### WAHR WAHR WAHR ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR ##### R+3 + 0.5 H2O = R+2 + H+ + 0.25 O2
R2(OH)2+4 WAHR WAHR ##### ##### WAHR ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### 2 H2O + 2 R+3 = R2(OH)2+4 + 2 H+
R3(OH)5+4 ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### 5 H2O + 3 R+3 = R3(OH)5+4 + 5 H+
R5(OH)9+6 ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### 9 H2O + 5 R+3 = R5(OH)9+6 + 9 H+
RBr+2 ##### ##### WAHR ##### ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### R+3 + Br- = RBr+2
RBr2+ ##### ##### ##### ##### ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### 2 Br- + R+3 = RBr2+
RCl+2 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR Cl- + R+3 = RCl+2
RCl2+ ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 Cl- + R+3 = RCl2+
RCl3 ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 3 Cl- + R+3 = RCl3
RCl4- ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 4 Cl- + R+3 = RCl4-
RCO3+ WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR HCO3- + R+3 = RCO3+ + H+
RF+2 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR F- + R+3 = RF+2
RF2+ WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 F- + R+3 = RF2+
RF3 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 3 F- + R+3 = RF3
RF4- ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 4 F- + R+3 = RF4-
RH2PO4+2 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR HPO4-2 + H+ + R+3 = RH2PO4+2
RHCO3+2 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR HCO3- + R+3 = RHCO3+2
RHPO4+ WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR HPO4-2 + R+3 = RHPO4+
RNO3+2 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR NO3- + R+3 = RNO3+2
RO+ ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR H2O + R+3 = RO+ + 2 H+
RO2- ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 H2O + R+3 = RO2- + 4 H+
RO2H ##### WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR 2 H2O + R+3 = RO2H + 3 H+
ROH(CO3)2-2 ##### ##### ##### ##### ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### 2 HCO3- + H2O + R+3 = ROH(CO3)2-2 + 3 H+
ROH+2 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR H2O + R+3 = ROH+2 + H+
ROHCO3 ##### ##### ##### ##### ##### ##### WAHR ##### ##### ##### ##### ##### ##### ##### ##### HCO3- + H2O + R+3 = ROHCO3 + 2 H+
RPO4 WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR HPO4-2 + R+3 = RPO4 + H+
RSO4+ WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR WAHR SO4-2 + R+3 = RSO4+
21
Solid Phases
AaBb = aA + bB ba
ba
ba
sp }B{}A{}BA{}B{}A{K
pure solid phase:1}BA{ ba
Note:
spsp KlogpK
insoluble: Ksp 1 soluble: Ksp > 1
pKsp 0pKsp < 0
22
Solid Solutions
pure solid phase: 1}BA{ ba
[University of Texas, El Paso]
solid solutions: 1}BA{ ba
- 23 -
Process Simulation (Example)
NORM Separation of Monazite by Caustic Soda
(REE, Th, U) PO4
24
Ion Exchange
Soils & Aquifers
Na+ + X- = NaX
½ Ca+2 + X- = Ca0.5X
…
(clay minerals)
R+ + Cl- = RCl
R+ + ½ SO4-2 = R(SO4)0.5
…
cation exchange anion exchange
La+3 + 3Q- = LaQ3
Eu+3 + 3Q- = EuQ3
…
cation exchange
Technology (resin)
1D Reactive Transport (TRN)in
flow
= F
(t)
Layer A Layer B Layer C
Advection & Dispersion & Reactions
unlimited Number of aqueous species
unlimited Number of reactive minerals
unlimited Number of secondary minerals
unlimited Number of ion-exchange species
arbitrary Type(s) of KineticsPhreeqC-based
(C++)
IX Sorption & Elution (REE example)
Summary
28
Lessons Learnt (Part I)
Almost all models / software are of high-quality (and provide the same results).
The main problem: incomplete/wrong data & lack of experience.
input data, paramsthdyn. dataset
range of applicability
29
Lessons Learnt (Part II)
How to convert measured data (from lab) intoinput dataset ?
How to handle uncertainties ?
Still Open Questions in Hydrochemistry:
30
Lessons Learnt (Part III)
Model developers are drawn to complexity like moth to a flame.
Resist the temptation: Start with simple & robust models.
avoid 2nd order corrections etc.
Don’t be too clever.
31
Benefits of Modeling
No model, no data is perfect. But knowing the limitswe are able to
gain deep insight about the system (step by step) uncover “hidden” domains (inside columns, heaps) design & interpret lab test simulate & optimize processes
Need: Healthy mix of practice (lab & field work) and theory.