SIST-TS CEN/TS 14429:2006
(Main)Characterization of waste - Leaching behaviour tests - Influence of pH on leaching with initial acid/base addition
Characterization of waste - Leaching behaviour tests - Influence of pH on leaching with initial acid/base addition
This Technical Specification is applicable to determine the influence of pH on the leachability of inorganic constituents from a waste material. Equilibrium condition as defined in the standard is established by addition of pre-determined amounts of acid or base to reach desired end pH values. This test method produces eluates, which are subsequently characterized physically and chemically.
This Technical Specification is a parameter specific test as specified in ENV 12920. The application of this test method alone is not sufficient for the determination of the detailed leaching behaviour of a waste under specified conditions.
NOTE This generally requires the application of several test methods, behavioural modelling and model validation as specified in ENV 12920.
Charakterisierung von Abfällen - Untersuchung des Auslaugungsverhaltens - Einfluss des pH-Wertes unter vorheriger Säure/Base Zugabe
Diese Technische Spezifikation gilt für die Bestimmung des Einflusses des pH-Wertes auf die Auslaugbarkeit
von anorganischen Bestandteilen aus einem Abfall. Der Gleichgewichtszustand, wie er in diesem Dokument
definiert ist, wird durch Zugabe einer vorher bestimmten Menge an Säure oder Base hergestellt, um die
gewünschten endgültigen pH-Werte zu erreichen. Dieses Prüfverfahren führt zu Eluaten, die anschließend
physikalisch und chemisch charakterisiert werden.
Diese Technische Spezifikation ist eine parameterspezifische Prüfung, wie in ENV 12920 festgelegt. Die
Anwendung nur dieses Prüfverfahrens ist für die Bestimmung des genauen Auslaugungsverhaltens eines
Abfalls unter festgelegten Bedingungen nicht ausreichend.
ANMERKUNG Dies erfordert im Allgemeinen die Anwendung mehrerer Prüfverfahren, die Verhaltensmodellierung und
Validierung von Modellen, wie in ENV 12920 festgelegt.
Caractérisation des déchets - Essais de comportement a la lixiviation - Influence du pH sur la lixiviation avec ajout initial d'acide/base
La présente Spécification technique s’applique a la détermination de l’influence du pH sur la lixiviabilité des constituants inorganiques d’un déchet. L’état d’équilibre tel que défini dans la norme s’obtient en ajoutant des quantités prédéfinies d’acide ou de base pour atteindre les valeurs de pH souhaitées. Cette méthode d’essai produit des éluats qui sont ensuite caractérisés du point de vue physico-chimique.
La présente Spécification technique est un essai paramétrique, tel que spécifié dans l’ENV 12920. Cette méthode d’essai n’est pas suffisante, a elle seule, pour déterminer en détail le comportement a la lixiviation d’un déchet dans des conditions spécifiées.
NOTE En regle générale, ceci nécessite l’application de plusieurs méthodes d’essai, une modélisation du comportement, ainsi qu’une validation du modele, comme spécifié dans l’ENV 12920.
Karakterizacija odpadkov – Izluževalni preskusi – Vpliv pH na izluževanje z začetnim dodatkom kisline/baze
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TS CEN/TS 14429:2006
01-maj-2006
.DUDNWHUL]DFLMDRGSDGNRY±,]OXåHYDOQLSUHVNXVL±9SOLYS+QDL]OXåHYDQMH]
]DþHWQLPGRGDWNRPNLVOLQHED]H
Characterization of waste - Leaching behaviour tests - Influence of pH on leaching with
initial acid/base addition
Charakterisierung von Abfällen - Untersuchung des Auslaugungsverhaltens - Einfluss
des pH-Wertes unter vorheriger Säure/Base Zugabe
Caractérisation des déchets - Essais de comportement a la lixiviation - Influence du pH
sur la lixiviation avec ajout initial d'acide/base
Ta slovenski standard je istoveten z: CEN/TS 14429:2005
ICS:
13.030.01 Odpadki na splošno Wastes in general
SIST-TS CEN/TS 14429:2006 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TS CEN/TS 14429:2006
TECHNICAL SPECIFICATION
CEN/TS 14429
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2005
ICS 13.030.01
English Version
Characterization of waste - Leaching behaviour tests - Influence
of pH on leaching with initial acid/base addition
Caractérisation des déchets - Essais de comportement à la Charakterisierung von Abfällen - Untersuchung des
lixiviation - Influence du pH sur la lixiviation avec ajout initial Auslaugungsverhaltens - Einfluss des pH-Wertes unter
d'acide/base vorheriger Säure/Base Zugabe
This Technical Specification (CEN/TS) was approved by CEN on 11 February 2005 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 14429:2005: E
worldwide for CEN national Members.
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Contents
page
Foreword .3
Introduction.4
1 Scope.5
2 Normative references.5
3 Terms and definitions .5
4 Symbols and abbreviations.6
5 Principle.7
6 Reagents and laboratory devices.7
6.1 Reagents.7
6.2 Laboratory devices.7
7 Sampling.8
7.1 Laboratory sample.8
7.2 Preparation of test sample.8
7.3 Determination of dry residue .9
7.4 Test portion.9
8 Test procedure.9
8.1 Contact time.9
8.2 pH-range.9
8.3 Leaching test.10
8.4 Natural pH.12
9 Eluate treatment, storage and analysis .13
10 Blank test.13
11 Performance characteristics.13
12 Test report.13
Annex A (informative) Example of a data sheet .15
Annex B (informative) Operation and uses of the test: influence of pH on the leaching
behaviour.16
Annex C (informative) Preliminary determination of the acid/base consumption.20
Annex D (informative) Examples of acid and base neutralisation capacities for waste, soil,
sediment and construction materials.24
Bibliography.26
2
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Foreword
This CEN Technical Specification (CEN/TS 14429:2005) has been prepared by Technical Committee CEN/TC 292
“Characterisation of waste”, the secretariat of which is held by NEN.
The annexes A, B, C and D are informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and
United Kingdom.
3
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Introduction
This Technical Specification has been developed primarily to support the requirements for leaching behaviour
testing within EU and EFTA countries. Tests to characterize the behaviour of waste materials can generally be
divided into three categories. The relationship between these tests are summarized below:
1. “Basic characterization“ tests are used to obtain information on the short and long term leaching behaviour and
characteristic properties of waste materials. Liquid/solid (L/S) ratios, leachant composition, factors controlling
leachability such as pH, redox potential, complexing capacity, ageing of waste and physical parameters are
addressed in these tests.
2. “Compliance“ tests are used to determine whether the waste complies with a specific behaviour or with specific
reference values. The tests focus on key variables and leaching behaviour previously identified by basic
characterization tests.
3. “On-site verification“ tests are used as a rapid check to confirm that the waste is the same as that which has
been subjected to the compliance test(s). On-site verification tests are not necessarily leaching tests.
The test procedure described in this Technical Specification belongs to category (1): basic characterization tests.
In the test, which is described in this Technical Specification equilibrium condition is established at different pH
values as a result of the reaction between pre-selected amounts of acid or base and test portions of the waste
material. Size reduction is performed to accelerate reaching of equilibrium condition.
This test is different from the "pH dependence test with continuous pH control" (pH static test see prEN 14997) in
which the pH is controlled at pre-selected values over the entire testing period by continuous measurement and
automatic addition of acid or base. The test is aiming at approaching equilibrium at the end of the procedure.
NOTE In Annex B specific uses of both the pH dependence test with initial acid/ base addition and the pH dependence test
with continuous pH control are indicated.
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1 Scope
This Technical Specification is applicable to determine the influence of pH on the leachability of inorganic
constituents from a waste material. Equilibrium condition as defined in the standard is established by addition of
pre-determined amounts of acid or base to reach desired end pH values. This test method produces eluates, which
are subsequently characterized physically and chemically.
This Technical Specification is a parameter specific test as specified in ENV 12920. The application of this test
method alone is not sufficient for the determination of the detailed leaching behaviour of a waste under specified
conditions.
NOTE This generally requires the application of several test methods, behavioural modelling and model validation as specified
in ENV 12920.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
EN 12506:2003, Characterization of waste – Analysis of eluates – Determination of pH, As, Ba, Cd, Cl-, Co, Cr,
CrVI, Cu, Mo, Ni, NO2-, Pb, total S, SO42- and Zn.
ENV 12920, Characterization of waste – Methodology for the determination of the leaching behaviour of waste
under specified conditions.
EN 13370, Characterization of waste – Analysis of eluates – Determination of Ammonium, AOX, conductivity, Hg,
- -
phenol index, TOC, easily liberatable CN , F .
prEN 14346:2002, Characterization of waste – Calculation of dry matter by determination of dry residue and water
content.
prEN 14899, Characterization of waste –- Sampling of waste materials - Framework for the preparation and
application of a Sampling Plan.
EN ISO 5667-3, Water quality – Sampling – Part 3: Guidance on the preservation and handling of samples (ISO
5667-3:2003).
3 Terms and definitions
For the purposes of this Technical Specification, the following terms and definitions apply.
3.1
dry residue
w
dr
remaining mass fraction of a sample after a drying process at 105 °C
[prEN 14346:2002]
3.2
eluate
solution obtained by a laboratory leaching test
3.3
equilibrium condition
condition achieved when the pH deviation during a checking period at the last 4 hours of the test is below 0,3 pH
unit
5
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3.4
laboratory sample
sample or subsample(s) sent to or received by the laboratory
[IUPAC, 1997]
3.5
liquid to solid-ratio
L/S
ratio between the amount of liquid (L) and of solid (S) in the test
NOTE L/S is expressed in l/kg dry matter.
3.6
leachant
liquid to be mixed with the test portion in the leaching procedure
3.7
suspension
mixture of leachant and test portion
3.8
test portion
amount or volume of the test sample taken for analysis, usually of known weight or volume
[IUPAC, 1997]
3.9
test sample
sample, prepared from the laboratory sample, from which test portions are removed for testing or analysis
[IUPAC, 1997]
4 Symbols and abbreviations
ANC acid neutralization capacity
BNC base neutralization capacity
DM dry matter
DOC dissolved organic carbon
L/S liquid to solid ratio
M dried mass of the test portion
d
m mass after drying
d
M un-dried mass of the test portion
w
m mass before drying
r
t time at the start of the leaching test
0
V volume of acid or base used in leachant
A/B
V volume of demineralized water used in leachant
demin
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V volume of added leachant
L
w dry residue of the waste
dr
5 Principle
Separate test portions are leached at a fixed L/S ratio with leachants containing pre-selected amounts of acid or
base in order to reach stationary pH values at the end of the extraction period. Each leachant is added in three
steps in the beginning of the test. At least 8 final pH-values are required, covering at the minimum the range
pH 4 to pH 12 (both included i.e. the lowest value ≤4 and the highest value ≥12). The amounts of acid or base
needed to cover the pH range can be derived from the results of a preliminary titration, from available experimental
data on the material to be tested or from an arbitrary division of the predetermined maximum consumption of acid
and base. The tests are carried out at a fixed contact time at the end of which equilibrium condition can be
assumed to be reached for most constituents in most waste materials to be characterized. The equilibrium
condition as defined in the standard is verified at the end of the extraction period.
The results are expressed in mg/l of constituents for each final pH value. For each final pH value also the quantity
+
of acid that is added is expressed in mol H /kg DM and the quantity of base that is added is expressed as negative
- -
mol OH /kg DM (-mol OH /kg DM).
NOTE 1 Other expression of results is possible (including mg leached /kg dry matter). Since this test is aiming at equilibrium
condition i.e. solubility controlled, the results alone cannot be used to quantify the soluble mass fraction.
The acid or base neutralization capacity (ANC, BNC) of the waste is also determined.
NOTE 2 The pH range covered by the test may be restricted to a pH range relevant for the specific material and the considered
problem (see 8.2).
6 Reagents and laboratory devices
6.1 Reagents
6.1.1
Distilled water, demineralized water or water of equivalent purity with a conductivity < 0,1 mS/m
6.1.2
Nitric acid (pro analysis), 0,1 mol/l to 5 mol/l
6.1.3
Nitric acid (pro analysis), 1 mol/l
6.1.4
Sodium hydroxide, NaOH, 0,1 mol/l to 5 mol/l
6.2 Laboratory devices
6.2.1
Agitation device: end-over-end tumbler (5 r/min to 10 r/min) or roller table rotating at about 10 r/min
6.2.2
Analytical balance (accurate to 0,1 g)
6.2.3
Bottles (250 ml for the test portions of 15 g of dry mass, 500 ml for test portions of 30 g dry mass and 1 l for test
portions of 60 g dry mass) made of polypropylene (PP) or polyethylene (PE).
6.2.4
Crushing equipment, e.g. a jaw crusher
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NOTE Crushing is prescribed to avoid unnecessary grinding to very fine particle sizes, such as takes place in a rotary swing
mill, ball mill or similar device.
6.2.5
Membrane filters for the filtration device, fabricated from inert material, which is compatible with the waste and has
a pore size of 0,45 µm. Filter shall be pre-rinsed with demineralised water or similarly clean in order to remove
DOC.
6.2.6
pH meter with a measurement accuracy of at least ± 0,05 pH units
NOTE At high pH values the use of specific electrodes is recommended.
6.2.7
Sample splitters for a minimum test portion size equivalent of 15 g of dry mass
6.2.8
Sieving equipment with sieve of 1mm nominal screen sizes
NOTE Due to crushing and sieving, contamination of the sample may occur to an extent, which can affect the leached
amounts of some constituents of concern, e.g. Co and W from tungsten carbide crushing equipment or Cr, Ni, Mo and V from
stainless steel equipment.
6.2.9
Vacuum filtration device or pressure filtration device
7 Sampling
7.1 Laboratory sample
The laboratory sample shall consist of a mass equivalent of at least 1 kg of dry mass.
Perform sampling in accordance with draft prEN 14899 or a standard derived from prEN 14899 in order to obtain a
representative laboratory sample.
7.2 Preparation of test sample
The tests shall be made on material with a grain size of 95 % less than 1 mm. In order to ensure that the test
sample consists in 95 % mass of particles less than 1 mm in diameter, it shall be sieved, using the sieving
equipment (see 6.2.8), to separate the oversized particles. If oversized material exceeds 5 % (mass), the entire
oversized fraction shall be crushed. Any non-crushable material (e.g. metallic parts such as nuts, bolts, scrap) shall
be separated from the oversized fraction and the weight and nature of the non-crushable material shall be
recorded. Crushed and uncrushed material shall be mixed to constitute the test sample.
Moist material that is not possible to sieve needs to be dried prior to sieving and/or crushing. The drying
temperature shall not exceed 40 °C.
NOTE 1 There is no obligation to sieve if it is obvious that the material will fully pass the sieve on 1 mm.
NOTE 2 The crushed material can change upon storage due to ageing of fresh surfaces. It is therefore preferable to test the
material as soon as possible after crushing.
NOTE 3 It is recommended that materials with a high natural pH be crushed under nitrogen in order to avoid contact with air
leading to carbonation.
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7.3 Determination of dry residue
The whole test sample, complying with the size criteria in 7.2 shall not be further dried. The dry residue (w ) of the
dr
test sample shall be determined on a separate test portion.
The dry residue shall be determined at 105 °C ± 5 °C according to prEN 14346. The dry residue is calculated as
follows:
m
d
w =100⋅ (1)
dr
m
r
where
w is the dry residue of the waste expressed as a percentage (%);
dr
m is the mass after drying expressed in grams (g);
d
m is the mass before drying expressed in grams (g).
r
7.4 Test portion
Prepare at least 8 test portions by the use of a sample splitter or by coning and quartering. Based on sample
heterogeneity and eluate volume requirement for analysis, test portion size shall be either M = 15 g, 30 g or 60 g
d
(with a tolerance of ± 10 %).
Calculate the undried mass of the test portion M to be used for the test as follows:
w
M
d
M = ⋅100 (2)
w
w
dr
where
M is the dried mass of the test portion expressed in grams (g);
d
M is the undried mass of the test portion expressed in grams (g);
w
w is the dry residue of the waste expressed as percentage (%).
dr
8 Test procedure
8.1 Contact time
The leaching procedure consists of three defined stages:
• Period A (acid/base addition) from t up t +4 h for acid/base addition in three steps;
0 0
• Period B (equilibration period) from t up to t +44 h equilibration period;
0+4 h 0
• Period C (verification period) from t up to t +48 h for verification of equilibrium condition.
0+44 h 0
Measure pH in the liquid after each of these periods.
The total contact period (A+B+C) is 48 h.
8.2 pH-range
The test shall cover the range pH 4 to pH 12 (both included i.e. the lowest value ≤4 and the highest value ≥12) with
at least 8 pH values tested including the natural pH (without acid or base addition). The maximum difference
between two consecutive pH values shall not exceed 1,5 pH units.
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NOTE 1 To ensure that the appropriate pH values can be obtained in one run additional bottles can be prepared of which only
the ones with the desired final pH values are retained for analysis.
NOTE 2 The pH range covered by the test may be restricted to a pH range relevant for the specific material and the considered
problem. The pH range to be covered can depend on the specific properties of the waste material, the available information on
this material and the questions to be answered by performing the test. The number of pH levels considered can be reduced,
correspondingly.
8.3 Leaching test
8.3.1 General
The following procedure applies for each of the chosen pH values to be tested.
8.3.2 Preparation of leachant
+ +
Identify the acid or base consumption for reaching the relevant pH values as A (mol H /kg DM) or B (mol H /kg
DM).
NOTE 1 The acid or base consumption for the considered pH values may be derived from available information, from the
preliminary procedures in Annex C or from information in Annex D.
Calculate the volume V of liquid to establish L/S = 10 l/kg ± 0,2 l/kg for the actual size of test portion M (see 7.4)
w
including the volume of acid or base.
V = 10 ⋅M (3)
d
where
V is the total volume of liquid in the test in ml;
M is the dry mass of the test portion expressed in grams (g) (see 7.4);
d
NOTE 2 In relation to L/S-ratio, V in this equation is equivalent with the ”L” and M is equivalent to the “S”.
d
Calculate the amount of leachant to be added to the actual size of test portion and compensate for the moisture
content in the test portion, as follows:
100
V =V − ( −1) ⋅M (4)
L d
w
dr
where
V is the total volume of liquid in the test in ml;
M is the dry mass of the test portion expressed in grams (g) (see );
7.4
d
w is the dry residue of the waste expressed as percentage % (see 7.3);
dr
V is the volume of leachant to be added expressed in millilitres (ml).
L
Prepare the leachant from demineralized water (see 6.1.1) and acid or base (see 6.1.2 or 6.1.4) according to the
acid/base consumption for the relevant pH.
Prepare the acid adjusted leachant as follows:
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V =V +V (5)
L de min A
A⋅M
d
V = (6)
A
C
A
where
V is the volume of prepared leachant expressed in millilitres (ml);
L
V is the volume of demineralized water used expressed in millilitres (ml);
demin
V is the volume of acid needed expressed in millilitres (ml);
A
+
A is the acid consumption for the pH in mol H /kg DM;
M is the dry mass of the test portion expressed in grams (g) (see 7.4);
d
C is the concentration of the acid expressed in mol per litre (m/l) (see 6.1.2).
A
Prepare the base adjusted leachant as follows:
V =V +V (7)
L de min B
B ⋅M
d
V = (8)
B
C
B
where
V is the volume of prepared leachant expressed in millilitres (ml);
L
V is the volume of demineralized water used expressed in millilitres (ml);
demin
V is the volume of base needed expressed in millilitres (ml);
B
-
/kg DM;
B is the base consumption for the pH, mol OH
M is the dry mass of the test portion expressed in grams (g) (see 7.4);
d
C is the concentration of the base expressed in mole per litre (mol/l) (see 6.1.4).
B
Split the volume V of leachant into 3 equal fractions V /3.
L L
8.3.3 Leaching procedure
Carry out the test at a temperature of 20 °C ± 5 °C.
Select the appropriate bottle size according to the test portion size. For M =15 g, 30 g and 60 g, this means
d
respectively bottle sizes of 250 ml, 500 ml and 1 000 ml.
Clean the bottle before use by filling it with 1 mol/l nitric acid (see 6.1.3), leaving it for at least 24 h and then
flushing it out with demineralized water (see 6.1.1).
Place one of the test portions in the rinsed bottle.
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Add the leachant volume V /3 at three different times:
L
st
— 1 fraction at t ;
0
nd
— 2 fraction at t +30 min;
0
rd
— 3 fraction at t +2 h.
0
Close the bottle and agitate the suspension (see 6.2.1) between each leachant addition. Measure and record pH
before addition of fractions 2 and 3, and prepare additional bottles with modified acid/base addition, if deviations
are observed from the expected pH at that time.
Continue to agitate after the last leachant addition until t= t .
0+48 h
NOTE 1 For some waste materials gas formation may occur (e.g. CO2, H2). It is recommended to pay attention when opening
the bottles to release the pressure (preferably in a fume hood).
NOTE 2 For the high pH values (pH>9) CO2 uptake may affect the leaching process. This may be reduced by minimizing the
contact time with the air during handling.
Measure and record the pH at t , t , t . For the measurement of pH stop the agitation and allow the mix to
0+4 h 0+44 h 0+48 h
settle for 5 min. Measure pH by inserting the electrode into the leachant in the bottle.
NOTE 3 The pH value at t is used for checking that sufficient pH correction has been obtained by the acid or base additions.
0+4 h
Since the pH is measured directly in the suspension, rinse the pH electrode thoroughly and dry before and between
uses in order not to contaminate the suspension.
The pH value measured before filtration at t will be the one associated to the analysis of the eluate.
0+48 h
NOTE 4 pH is measured directly in the bottle at t since filtration can change pH in the eluate.
0+48 h
Report the pH deviation between t and t .
0+4h 0+44h
The deviation between pH at t and pH at t shall not exceed 0,3 pH units, which is the limit for achieving
0+44h 0+48 h
equilibrium condition (see 3.3). A special note shall be made in the report if this requirement is not met.
If too many experimental points deviate (more than 3 amongst 8), the conclusion is that this test is not applicable to
this material.
NOTE 5 When equilibrium condition is strictly compulsory for specific use but not fulfilled in the test, it is possible to continue the
test to maximum 7 days for all the 8 experimental points (selected pH values) in order to avoid association of results at 48 h with
th
those at longer leaching time. In this case, pH deviation could be limited to 0,3 pH units for the last 24h (maximum between 6
th
and 7 days).
The experimental point(s), which do not conform to these new conditions, will not be exploited and this fact shall be
mentioned in the report. This specific procedure is not part of this Technical Specification.
Allow the suspended solids to settle for 15 min ± 5 min.
Rinse the part of filtration device (see ), which is in contact with the eluate with nitric acid (see ), and flush
6.2.9 6.1.3
with ultra pure water before any use.
Filter the suspension through a 0,45 µm membrane filter (see 6.2.5) using the filtration device (see 6.2.9).
Proceed immediately with the eluate treatment as specified in Clause 9.
8.4 Natural pH
Repeat 8.3 for a test portion without acid or base addition, when determining the volume of demineralized water to
be added. Measure of pH after 4 h, 44 h and 48 h as in 8.3.
NOTE A very low conductivity in the eluate at natural pH may increase generation of colloids, which may clog filters and
increase analyzed concentrations. This can be avoided by addition of NaNO in the leachant at a concentration comparable to
3
the concentration of acid or base in the closest pH values tested.
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The use of NaNO (amount and concentration) shall be reported.
3
9 Eluate treatment, storage and analysis
Divide the eluate into an appropriate number of sub-samples for different chemical analysis. Preserve the eluate
sub-samples depending on the elements to be analysed and store them, in accordance with t
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