Harmonisation of leaching test methods in support of EU ......CEN/TS 14997 Chemical speciation...
Transcript of Harmonisation of leaching test methods in support of EU ......CEN/TS 14997 Chemical speciation...
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Harmonisation of leaching test methods in support of EU regulations controlling beneficial use of industrial slag in constructionHans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
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Outline
Status of standardisation of leaching tests
Regulatory context
Leaching test results for steel slag
Use of leaching test in assessing impact
Practicality of testing
Benchmarking
28/04/20112 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
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pH Dependence test
nchemicalanalyses
LnLBLA
n samples
S2 SnnBA
S1
0.01
0.1
1
10
100
1000
2 4 6 8 10 12 14Leachate pH
Co
pp
er
[mg
/L]
Titration Curve and Liquid-solid Partitioning (LSP) Curve as Function of Eluate pH
3
Equilibrium Leaching Test Parallel batch as function of pH
Test Specifications 8 specified target pH values plus natural
conditions Size-reduced material L/S = 10 mL/g-dry Dilute HNO3 or NaOH Contact time
48 hours
Reported Data Equivalents of acid/base added Eluate pH and conductivity Eluate constituent concentrations
28/04/2011Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
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Advantages of pH dependence test
- Identification of sensitivity of leaching to small pH changes
- Provides information on pH conditions imposed by external influences
- Basis for comparison of international leaching tests
- Basis for geochemical speciation modelling
- Provides acid neutralization capacity information
- Mutual comparison of widely different materials to assess similarities in leaching behaviour
- Recognition of factors controlling release
- For non-interacting species possibility to assess sub-sampling error
Applicable to almost any material
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0.01
0.1
1
10
100
1000
1 3 5 7 9 11 13
pH
Lea
ch
ed
at
L/S
=1
0 (
mg
/kg
)
Cd
INGESTION
INHALATION
CEMENT STABILIZATION OF
CONTAMINATED SOIL
NATURAL SOIL
ACIDIC
ENVIRONMENTS
SOIL
LIMING
Test conditions related to differentexposure conditions
Relevant pH domains for assessing different questions in relation to different types of impact
Heavily Sewage Sludge Amended
Soil
Total
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Local Equilibrium Leaching Test
Percolation through loosely-packed material
Test Specifications
5-cm or 10 cm diameter x 30-cm high glass column
Size-reduced material
DI water or 1 mM CaCl2 (clays, organic materials)
Upward flow to minimize channeling
Collect leachate at cumulative L/S0.1, 0.2, 0.5, 1, 2, 5, 10 mL/g-dry
Reported Data Eluate volume collected Eluate pH and conductivity Eluate constituent concentrations
Percolation Test
air lock
eluant collection bottle(s)(sized for fraction volume)
Luer shut-offvalve
eluant reservoir
end cap
end cap
1-cm sandlayers
pump
subjectmaterial
Luer shut-offvalve
Luer fitting
Luer fitting
N2 or Ar (optional)
Liquid-solid Partitioning (LSP) Curve as Function of L/S; Estimate of Pore Water Concentration
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Advantages of percolation test
- Identification of solubility control versus wash out
- Indication of pore water concentrations relevant to field leachatefrom low L/S data (here is where single batch test fail)
- Local equilibrium established quite rapidly
- Basis for geochemical reaction-transport modelling
- Allows comparison with lysimeter and field data provided L/S value can be obtained from such measurements
- Projection towards long term behaviour possible (L/S-time relationship) taking preferential flow into account
Applicable to many materials. Limited or not applicable to clayey soils and sediments (low permeability).
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Monolith Leach test
Mass-Transfer Test
Semi-dynamic tank leach test
Test Specifications
Material forms monolithic (all faces exposed) compacted granular (1 circular face exposed)
DI water so that waste dictates pH
Liquid-surface area ratio (L/A) of 9±1 mL/cm2
Refresh leaching solution at cumulative times 2, 25, 48 hrs, 7, 14, 28, 42, 49, 63 days
Reported Data Refresh time Eluate pH and conductivity Eluate constituent concentrations
1 Sample
nanalyticalsamples
A1
L1
A2 An
L2 Ln
Δt1 Δtn
orMonolith
CompactedGranular
n Leaching Intervals
Δt2
Flux and Cumulative Release as a Function of Leaching Time
Granular
Monolithic
0.001
0.01
0.1
1
10
100
1000
0.01 0.1 1 10 100
Cr
Rele
ase [
mg
/m2]
Leaching Time [days]
Availability
MDL
ML
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Advantages of tank test or CGLT (compacted granular leach test)
- Relevant for materials with monolithic character (durable materials) or materials behaving as monolith (low permeability soil and sediments)
- Identification of solubility control versus dynamic leaching possible
- Isolation of surface wash-off effects
- Quantification of intrinsic release parameters
- Basis for reactive/transport modelling
- Projection towards long term behaviour possible
Applicable to stabilised materials, construction products, sediments and clayey soils.
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Development of Standards and Materials Covered
Test/Matrix
Soil, sediments,
compost and
sludge Waste Mining waste Construction products
pH dependence test ISO/TS21268-4 CEN/TS14429 CEN/TS14429 CEN/TS14429
CEN/TS14497 CEN/TS14497
EPA 1313 * EPA 1313 EPA 1313 EPA 1313
Percolation test ISO/TS21268-3 CEN/TS14405 CEN/TS14405 CEN/TC351/TS-3
EPA 1314 * EPA 1314 EPA 1314 EPA 1314
Monolith test CEN/TS15683 CEN/TC351/TS-2
EPA 1315 * EPA 1315 EPA 1315 EPA 1315
Compacted granular test NEN7347 CEN/TC351/TS-2
EPA 1315 EPA 1315 EPA 1315 EPA 1315
Redox capacity NEN 7348 NEN 7348
Acid rock drainage PrEN15875
Reactive surfaces
ISO/CD12782
parts 1-5
* EPA drafts in preparation for inclusion in SW846
Same basic testing approach in different fields
Vienna agreement
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Steps in validation
From: CEN Guide on validation tasks in the process of standardisation of environmental test methods, April 2008, ENV TC 215rev, supported by SABE Resolution 06/2008 -Validation policy
This is the status today:
- CEN/TC351 Robustness work granted (TS-2 and TS-3)
- US EPA Intercomparison validation in progress (pH dependence, percolation , monolith, CGLT) Results available end 2011
- CEN/TC292 still seeking funds
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Use in blended cement
Raw material input in cement production process
Aggregate in concrete
Road base stabilisation
Embankment fill
Coastal protection
Soil improver
Steel slag Uses
With multiple uses of the same material or product multiple testing and judment approaches undesirable.
Single step tests are clearly insufficient to answer questions related to possible environmental impact.
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Construction Products Directive (EU CPD)
Construction Products Regulation (EU CPR).
European Landfill Directive (EU LFD)
End of Waste regulation (EU EoW)
Waste Catalogue (EU WC)
Hazardous Waste Directive (EU HW)
REACH Regulation
Soil Quality Regulation – Fertilizer use
Groundwater Directive
Regulatory context
With multiple regulations : preferably not multiple testing and multiple impact judment approaches for the same material or product
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TANK LEACH TEST MONOLITH CEN/TS 15863 and EPA Draft method
1315 and COMPACTED
GRANULAR LEACH TEST (NEN 7347 and EPA method
1313).
PERCOLATION LEACHING TEST CEN TS 14405 or EPA Draft method
1314
GRANULAR MATERIALS
MONOLITHIC MATERIALS
or
pH DEPENDENCE TEST: BATCH MODE ANC, CEN/TS 14429, or EPA Draft method 1313or, COMPUTER CONTROLLED CEN/TS 14997
Chemical speciation aspects Time dependent aspects of release
Same as granular +
Standardisation: CEN/TC292, ISO/TC190, CEN/TC345, CEN/TC351, SW846 (US EPA)
Characterisation leaching tests
Test set covers almost any practical condition for any material
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Leaching of substances from granular materials is assessed by a column leaching test (CEN/TS14405) and pH dependence leaching test CEN TS/14429)
The column test provides insight in the release behaviour of substances.
Salts are generally not interacting with the matrix and thus released within a liquid to solid ratio (L/S) of 1
Many trace contaminants are solubility controlled
In a column upflow test preferential flow is minimized to ensure repeatability and reproducibility of test data
Under field conditions a substantial part of the application can be identified as stagnant (dual porosity model)
Release from granular materials
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Identification of release processes from testing of granular materials
0 .1
1
1 0
1 0 0
0 .1 1 1 0 1 0 0
L/S (l/k g )
Le
ac
he
d (
mg
/kg
)
F
SO L U B IL IT Y
C O N T R O L
F0 .1
1
1 0
1 0 0
4 6 8 1 0 1 2
pH
Le
ac
he
d a
t L
/S=
10
(mg
/kg
)
0 .0 1
0 .1
1
1 0
0 .1 1 1 0 1 0 0
L/S (l/k g )
Co
nc
en
tra
tio
n (
mg
/l)
F
Cl
1 0 0
1 0 0 0
1 0 0 0 0
4 6 8 1 0 1 2
pH
Le
ac
he
d (
mg
/kg
)
1 0 0
1 0 0 0
1 0 0 0 0
0 .1 1 1 0 1 0 0
L/S (l/k g )
Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
Cl
W A SH O U T
1
1 0
1 0 0
1 0 0 0
1 0 0 0 0
0 .1 1 1 0 1 0 0
L/S (l/k g )
Co
nc
en
tra
tio
n (
mg
/L) Cl
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0.01
0.1
1
10
100
1000
10000
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/k
g)
pH
pH dependent concentration of Cr
CEN/TS14429
Total
0.00001
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
0.01 0.1 1 10
Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
pH
Cumulative release of Cr
CEN/TS14405
Dutch SQD
Judgment of environmental impact ontotal composition or on leaching?
Relevance of total composition for environmental judgment questionable. Leaching by far more relevant for
environmental impact assessment and bioavailability
Steel slag BOF
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28/04/2011Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar18
Substances can be judged at different levels:
- Total content is generally a poor measure for environmental or health impact as often a small fraction of the total is assessible for uptake or transport
- Potentially leachable (available) is a next level, which can be considered a worst case approach
- Actual leaching in a pH and L/S domain of relevance to the application provides a good measure of possible exposure
- In some case chemical speciation can provide proof that the form in which substances are released is less harmful than assuming the most sensitive form
Understanding of chemical speciation is important for adequate control measures in case of product improvement
Judgment of environmental impact ontotal composition or on leaching?
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Data Management Tools
Data Templates Excel® Spreadsheets for Each Method
Perform basic, required calculations (e.g, moisture content)
Record laboratory data
Archive analytical data with laboratory information
Form the upload file to materials database
LeachXS (Leaching eXpert System) LiteTM
Data management, visualization and processing program
Compare Leaching Test Data Between materials for a single constituent (e.g., As in two different CCRs)
Between constituents in a single material (e.g., Ba and SO4 in cement)
To default or user-defined “indicator lines” (e.g., QA limits, threshold values)
Export leaching data to Excel spreadsheets
Freely available at http://www.vanderbilt.edu/leaching
Full LeachXSTM including geochemical tools (subscription fee)
19November 16,
2010EPA LTIG Conference Call
19
http://www.vanderbilt.edu/leaching
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Leaching behaviour of steel slag types
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0.00001
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH dependent concentration of Al
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
Cumulative release of Al
0.0001
0.001
0.01
0.1
1
10
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent concentration of Ba
0.0001
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
L/S (L/kg)
Cumulative release of Ba
Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
0.0001
10
2 12
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent
concentration of Ba
EAF
LD slag
Not specified
BF
BOF
-
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0.00001
0.0001
0.001
0.01
0.1
1
10
100
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH dependent concentration of Cr
0.00001
0.0001
0.001
0.01
0.1
1
10
0.01 0.1 1 10 100
Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
Cumulative release of Cr
0.00001
0.0001
0.001
0.01
0.1
1
10
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent concentration of Ni
0.00001
0.0001
0.001
0.01
0.1
1
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
L/S (L/kg)
Cumulative release of Ni
Leaching behaviour of steel slag types
0.0001
10
2 12
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent
concentration of Ba
EAF
LD slag
Not specified
BF
BOF
-
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0.0001
0.001
0.01
0.1
1
10
100
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH dependent concentration of V
0.00001
0.0001
0.001
0.01
0.1
1
10
100
1000
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
Cumulative release of V
0.00001
0.0001
0.001
0.01
0.1
1
10
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent concentration of Zn
0.0001
0.001
0.01
0.1
1
10
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
L/S (L/kg)
Cumulative release of Zn
Leaching behaviour of steel slag types
0.0001
10
2 12
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent
concentration of Ba
EAF
LD slag
Not specified
BF
BOF
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0.00001
0.0001
0.001
0.01
0.1
1
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH dependent concentration of Mo
0.00001
0.0001
0.001
0.01
0.1
1
10
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
Cumulative release of Mo
0.01
0.1
1
10
2 4 6 8 10 12 14
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent concentration of F
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100Cu
mu
lati
ve
re
lea
se
(m
g/k
g)
L/S (L/kg)
Cumulative release of F
Leaching behaviour of steel slag types
0.0001
10
2 12
Co
nce
ntr
ati
on
(m
g/L)
pH
pH dependent
concentration of Ba
EAF
LD slag
Not specified
BF
BOF
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- Different users of the release information have different needs. Both regulators and industry need information with sufficient detail to allow proper judgment of the materials in their intended use scenario.
Tiered approach in testing
Level of
detail
Frequency
of testing
“compliance” testing
“characterization” testing
Level of
detail
Frequency
of testing
“compliance” testing
“characterization” testing
Factory production control
Initial type testing/ Characterisation
- Once the release characteristics of a product type or class are established much simpler conformity testing will suffice for potentially critical parameters only at a frequency consistent with the risk of approaching/ exceeding set limit values by notified regulations.
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Statistics applied to consistent data sets for quality control purposes
28/04/201125
1E-05
1E-04
1E-03
1E-02
1E-01
1E+00
1E+01
1E+02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Conce
ntr
ation (m
g/L
)
pH
Cr
Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
Mean value for product type
Upper 90 % confidence interval
Lower 90 % confidence interval
Full test comparison
Single data point comparison
Benchmark Steel slag - pH dependence
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Role of Characterisation Leaching Tests in Environmental Judgement of Materials
Quality control of products Product improvement
Development of limit valuesRelation lab-practice (Scenarios)
Modelling
Product modificationMeasurement for verification
Efficient measurementsPrecision measurement data
Characterisation leaching tests(identification of mechanisms and
processes)
Assessibility of data: data base/expert system LeachXS
Development of criteria for regulation
Application of regulatory criteria
Judgement of applications
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Primary Raw Materials
Alternative raw materials
Stage 1 Raw material supplies
Stage 2:Manufacture of construction materials and elements
Recycling of construction debris
Stage 4:Service Life
Stage 3:Construction ProcessStage 5:
Demolition
Release into the environment
Energy
Dust, noise emissions
Energy
“End of Life”
Environmental impact (dusting)
Supply of information on technical and environmental
quality: Database/
expert system
Characterisation (ITT) of monolith/ granular leaching behaviour of the product
Monolith/granular QC, conformity or
compliance leaching test
Characterisation of granular leaching behaviour
Granularcompliance test
Tiered approach linked to the building cycle
28/04/201127 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
CPD -> CPR
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1. pH dependence leaching test on granular material or size reduced monolithic material for chemical speciation purposes
2. measurement of release from granular materials in a percolation test or from monolithic specimen according to a type of tank test
3. speciation modelling to identify relevant mineral phases (SI-indices)
4. refined description of multi element leaching behaviour in a pH dependence test based on the selected minerals and other relevant phases (Fe, Al, DOC, etc) providing a chemical speciation fingerprint (CSF)
5. the resulting chemical speciation fingerprint (CSF) is used as input for the chemical reaction/transport modelling to describe the release from a percolation test or from a monolithic specimen (tank test simulation).
6. model the field scenario using the CSFs for the different layers of material involved using external factors (carbonation, oxidation, biologically mediated reactions) and realistic estimates of infiltration (e.g. preferential flow)
Steps in chemical speciation modelling
28/04/201128 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
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Input (Chemical Speciation Fingerprint)
- Element availabilities (major minor and trace elements from pH dependence test)
- Liquid to Solid ratio (L/S=10)
- Redox status of material/product pH+pe = 15 (oxidised)
- Clay content (kg/kg)
- Reactive Hydrated Ironoxide surface (HFO in kg/kg)
- Reactive Solid Humic Acid (SHA in kg/kg)
- Dissolved Organic Carbon (DOC in kg/l from pH dependence test)
- Selection of potentially relevant minerals controlling solubility (Partly taken from a model run to determine saturation indices (SI) for all available minerals in the thermodynamic database)
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Example Input (Chemical Speciation Fingerprint)
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Prediction case Steelslag Carb + columnAA EA DOC/DHA data
Speciation session Steelslag Carb + columnAA EA pH [DOC] (kg/l) DHA fraction [DHA] (kg/l)Polynomial coeficients
Material Steel_slag_carbonated_30% (P,1,1) 1.00 2.000E-05 0.20 4.000E-06 C0 -5.775E+00
2.09 1.000E-05 0.20 2.000E-06 C1 6.397E-01
Solved fraction DOC 0.2 3.56 4.000E-06 0.20 8.000E-07 C2 -3.793E-01
Sum of pH and pe 15.00 5.19 4.250E-06 0.20 8.500E-07 C3 6.435E-02
L/S 10.4258 l/kg 6.49 1.000E-06 0.20 2.000E-07 C4 -4.332E-03
Clay 0.000E+00 kg/kg 8.07 1.000E-06 0.20 2.000E-07 C5 1.017E-04
HFO 3.000E-03 kg/kg 9.58 6.300E-06 0.20 1.260E-06
SHA 2.000E-04 kg/kg 11.42 7.100E-06 0.20 1.420E-06
Percolation materialsteelslag_Corus_K1RCS_treated_1 (C,1,1) 12.55 2.400E-06 0.20 4.800E-07
Avg L/S first perc. fractions 0.1495 l/kg 14.00 3.000E-06 0.20 6.000E-07
Reactant concentrations
Reactant mg/kg
Ag+ not measured Fe+3 1.573E+04 Mn+2 7.044E+03 SO4-2 1.011E+03
Al+3 4.689E+03 H2CO3 4.200E+04 MoO4-2 9.358E-02 Sr+2 8.935E+01
Ba+2 5.684E+01 H3AsO4 8.351E-01 Na+ 8.996E+01 VO2+ 7.311E+02
Ca+2 1.588E+05 H3BO3 3.080E+01 Ni+2 4.627E+00 Zn+2 2.103E+01
Cd+2 1.300E-01 H4SiO4 6.864E+03 Pb+2 4.871E+00
CrO4-2 6.560E+01 K+ 1.580E+02 PO4-3 1.016E+03
Cu+2 5.644E+00 Li+ 4.572E-01 Sb[OH]6- 3.464E-01
F- not measured Mg+2 1.211E+04 SeO4-2 2.407E+00
Selected Minerals
AA_2CaO_Al2O3_SiO2_8H2O[s] AA_Fe[OH]3[am] Barite Ca3[VO4]2 Fe2[MoO4]3[1] Ni[OH]2[s] Rhodochrosite
AA_2CaO_Fe2O3_SiO2_8H2O[s] AA_Gibbsite BaSrSO4[50%Ba] Ca4Cd[PO4]3OHFerrihydrite Ni2SiO4 Sphalerite
AA_3CaO_Al2O3[Ca[OH]2]0_5_[CaCO3]0_5_11_5H2O[s] AA_Gypsum beta-TCP Calcite Fluorite OCP Strengite
AA_3CaO_Al2O3_6H2O[s] AA_Portlandite Boehmite CaMoO4[c] Huntite Otavite Strontianite
AA_3CaO_Al2O3_CaCO3_11H2O[s] AA_Tobermorite-I Brucite Cd[OH]2[C] Laumontite Pb[OH]2[C] Tenorite
AA_3CaO_Fe2O3_CaCO3_11H2O[s] AA_Tricarboaluminate Ca_Vanadate Cr[OH]3[A] Magnesite Pb2V2O7 Wairakite
AA_Calcite Ba[SCr]O4[96%SO4] Ca2Cd[PO4]2 Diaspore Manganite Pb3[VO4]2 Willemite
AA_CO3-hydrotalcite BaCaSO4[75%Ba] Ca2V2O7 Fe_Vanadate Morenosite PbMoO4[c] ZnSiO3
Input specification
-
Chemical speciation modelling of carbonated steel slag
28/04/201131 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
-15
-10
-5
0
5
10
15
1 3 5 7 9 11 13
AN
C/B
NC
(m
ol/
kg
)
ANC/BNC
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Al
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Ca
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
Fe
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
Si1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
PO4 as PCEN/TS14429
CEN/TS14405Percolation
Model description at L/S=10
Model prediction at L/S=0.2
-
28/04/201132 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
Ni
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
Pb1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
Zn
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
Cr
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
Mo
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
V
Chemical speciation modelling of carbonated steel slag
CEN/TS14429
CEN/TS14405Percolation
Model description at L/S=10
Model prediction at L/S=0.2
Controlling phase missing
-
Ca and Zn leaching description and partitioning
28/04/201133 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
[Ca+2] as function of pH
Steel slag Carbonated TS14429
Model description L/S=10
Steelslag Carbonated TS14405
Model prediction L/S=0.2
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
Partitioning liquid-solid, [Ca+2]
FreePOM-boundFeOxideEttringiteAA_2CaO_Al2O3_SiO2_8H2O[s]AA_2CaO_Fe2O3_SiO2_8H2O[s]AA_3CaO_Al2O3_6H2O[s]AA_3CaO_Fe2O3_CaCO3_11H2O[s]AA_CalciteAA_Tobermorite-Ibeta-TCPCa2V2O7Laumontite
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
[Zn+2] as function of pH
1.0E-11
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid-solid, [Zn+2]
Free
DOC-bound
POM-bound
FeOxide
ZnSiO3
-
Mo and V leaching description and partitioning
28/04/201134 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
[MoO4-2] as function of pH
1.0E-08
1.0E-07
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
Partitioning liquid-solid, [MoO4-2]
Free
POM-bound
FeOxide
Fe2[MoO4]3[1]
PbMoO4[c]
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
[VO2+] as function of pH
Steel slag Carbonated TS14429
Model description at L/S=10
Steelslag Carbonated TS14405
Model prediction at L/S=0.2
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
Partitioning liquid-solid, [VO2+]
Free POM-bound
FeOxide Ettringite
Ca2V2O7 Fe_Vanadate
Pb2V2O7
Solubility control for V at pH10 -11 and L/S 0.2 - 10
Mo largely mobile at pH 10-11 –wash out
-
Why is speciation and partitioning important?
- The chemical form of elements dictates their potential environmental risk
- Whether Cr is present as chromate, Cr III or Cr-DOC complex has significant consequences for the actual impact
- Chromate (Cr VI) generally present in coal fly ash at pH > 8 is more toxic than Cr III
- Cr III – DOC complex is almost as mobile as chromate and may travel relatively fast through soil. The two forms should not be confused.
- DOC complexation of metals is important for their ecotoxicity as many organisms are insensitive to DOC complexed metals
- Understanding speciation allows focussed material management
28/04/201135 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
-
Processes in a Road Base Application - definitions
Road shoulder, soil
Road stabilisation material (e.g.
alternative construction material)Precipitation
Physical factors:
Permeability
Particle size
Porosity
Chemical factors:
pH
Organic matterBuffer capacity
RedoxChemical form (speciation)
Soluble salts
Transport
mechanisms:
Surface run-off
Percolation
Chemical
mechanisms:
Solubility control
Adsorption
Dispersion
Groundwater flow
Release scenario or source term description
(producer)
Impact assessment (regulator)
= Intended useO2CO2
Conditions during intended use
28/04/201136 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
-
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100
L/S
Cr
(mg
/k
g)
100
1000
10000
0.01 0.1 1 10 100
L/S
Cl
(mg
/k
g)
Prediction leachate quality taking preferential flow into account (80% stagnant- dual porosity model)
10010000
0.01 100
L/S
Landgraaf kolomtest
Model praktijk
Availability
Model kolomtest
Cd affected by substantially reduced Cl release, other metals not influenced (solubility controlled). Cl substantially reduced by preferential flow
0.01
0.1
1
10
100
1000
0.01 0.1 1 10 100
L/S
Cu
(m
g/k
g)
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100
L/S
Cd
(m
g/k
g)
28/04/201137 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
-
Impact Evaluation and Criteria Development
soil: unsaturated
zone
saturated zone (groundwater
transport)
Material
(e.g.,
aggegate)
possible liner (e.g., road)
source term
pathpoint of compliance (object)
Depending on the modeled groundwater quality at
the POC (which might be chosen anywhere), limits
to the release of the construction products might
be adjusted such that the product eventually
complies with the groundwater limit value at the
POC.
Time
Co
ncen
tra
tio
n.
at
PO
C
Groundwater
limit value
Time
Co
ncen
tra
tio
n.
at
PO
C
Groundwater
limit value
POC = point of compliance
Approach with POC in groundwater applied for EU LFD, Dutch BMD and Dutch SQD
28/04/201138 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
-
Conclusions
A limited set of proper characterisation tests suffices to describe release behaviour from materials and products in a variety of applications
Harmonisation and horizontal standardisation is possible
Significant progress in understanding release controlling processes has been made
Test results can not be compared directly with water quality criteria, as mimicking the field in the lab is generally not possible.
Many substances are solubility controlled, thus providing a good understanding of effects at longer term.
Highly soluble substances are generally most sensitive from an impact assessment perspective (initial peak concentrations).
The multi-element multi-phase chemical reaction transport modelling is a challenge, but a highly rewarding one, when the behaviour of steel slag in laboratory tests can be described.
28/04/201139 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
-
Recommendations
Emphasize release based judgment as opposed to content based judgment for environmental impact purposes
Bring together more data on steel slag leaching to be able to define the bandwidth of release behaviour
Generate information where gaps are identified
Steel slag release behaviour is process related and thus sharing test data at global scale makes a lot of sense
Develop benchmark characterisation data for steel slag and where needed subdivided for specific steel slag types - LeachXS Lite (free) can provided such service
28/04/201140 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar
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Thank you for your attention
Questions?
28/04/201141 Harmonisation of leaching test methods │ Hans van der Sloot, Andre van Zomeren, Rob Comans and Ole Hjelmar