EN 900:2007

SLOVENSKI STANDARD
01-januar-2008
1DGRPHãþD
SIST EN 900:2000
Kemikalije, ki se uporabljajo za pripravo pitne vode - Kalcijev hipoklorit
Chemicals used for treatment of water intended for human consumption - Calcium
hypochlorite
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch -
Calciumhypochlorit
Produits chimiques utilisés pour le traitement de l'eau destinée a la consommation
humaine - Hypochlorite de calcium
Ta slovenski standard je istoveten z: EN 900:2007
ICS:
13.060.20 Pitna voda Drinking water
71.100.80 .HPLNDOLMH]DþLãþHQMHYRGH Chemicals for purification of
water
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 900
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2007
ICS 71.100.80 Supersedes EN 900:1999
English Version
Chemicals used for treatment of water intended for human
consumption - Calcium hypochlorite
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Hypochlorite de menschlichen Gebrauch - Calciumhypochlorit
calcium
This European Standard was approved by CEN on 23 September 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, 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
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 900:2007: E
worldwide for CEN national Members.

Contents
Foreword.4
Introduction .5
1 Scope .6
2 Normative references .6
3 Description .6
3.1 Identification.6
3.1.1 Chemical name.6
3.1.2 Synonym or common name.6
3.1.3 Relative molecular mass.6
3.1.4 Empirical formula.6
3.1.5 Chemical formula.6
3.1.6 CAS Registry Number .7
3.1.7 EINECS reference .7
3.2 Commercial form .7
3.3 Physical properties.7
3.3.1 Appearance .7
3.3.2 Density .7
3.3.3 Solubility in water .7
3.3.4 Vapour pressure .7
3.3.5 Boiling point at 100 kPa .7
3.3.6 Melting point.7
3.3.7 Specific heat.7
3.3.8 Viscosity, dynamic.7
3.3.9 Critical temperature.7
3.3.10 Critical pressure.8
3.3.11 Physical hardness .8
3.4 Chemical properties .8
4 Purity criteria.8
4.1 General.8
4.2 Composition of commercial product.8
4.3 Impurities and main by-products.8
4.4 Chemical parameters .9
5 Test methods.9
5.1 Sampling.9
5.2 Analysis .9
5.2.1 Determination of calcium hypochlorite content (main product).9
5.2.2 Dissolution quality (available chlorine after 1 min).11
5.2.3 Impurities.13
5.2.4 Chemical parameters .15
6 Labelling - Transportation - Storage.17
6.1 Means of delivery.17
6.2 Risk and safety labelling according to the EU Directives .18
6.3 Transportation regulations and labelling.18
6.4 Marking .19
6.5 Storage.19
6.5.1 General.19
6.5.2 Long term stability.19
6.5.3 Storage incompatibilities .20
Annex A (informative)  General information on calcium hypochlorite .21
A.1 Origin .21
A.1.1 Raw materials.21
A.1.2 Manufacturing process .21
A.2 Use .21
A.2.1 Function.21
A.2.2 Form in which it is used.21
A.2.3 Treatment dose .21
A.2.4 Means of application .21
A.2.5 Secondary effects.21
A.2.6 Removal of excess product.22
Annex B (normative)  General rules relating to safety .23
B.1 Rules for safe handling and use .23
B.2 Emergency procedures.23
B.2.1 First aid.23
B.2.2 Spillage .23
B.2.3 Fire .23
Annex C (normative) Determination of arsenic, antimony and selenium (atomic absorption
spectrometry hydride technique).24
C.1 General principle .24
C.2 Interferences .24
C.3 Reagents.24
C.4 Apparatus .26
C.4.1 General.26
C.4.2 Atomic absorption spectrometer .26
C.4.3 Atomizer .26
C.5 Procedure .27
C.5.1 Preparation of the apparatus.27
C.5.2 Preparation of calibration solutions.28
C.5.3 Preparation of test solutions and standard solutions.28
C.5.4 Determination of arsenic with sodium borohydride .28
C.5.5 Determination of selenium with sodium borohydride .28
C.5.6 Determination of antimony with sodium borohydride.29
C.6 Calculation .29
C.7 Repeatability limit .29
Annex D (informative) .30
Environmental, health and safety precautions within chemical laboratory .30
Bibliography.31
Foreword
This document (EN 900:2007) has been prepared by Technical Committee CEN/TC 164 “Water supply”, the
secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by May 2008, and conflicting national standards shall be withdrawn at the latest by
May 2008.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 900:1999.
Significant technical differences between this edition and EN 900:1999 are as follows:
a) deletion of the reference to EU Directive 80/778/EEC of 15 July 1980 in order to take account of the latest
Directive in force (see [1]);
b) amended values regarding the maximum water content and water soluble substance;
c) updated references in regard to the determination of mercury;
d) revision of warning and safety precautions notes;
e) incorporation of Annex D (informative).
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,
Switzerland and the United Kingdom.

Introduction
With respect to potential adverse effects on the quality of water intended for human consumption caused by the
product covered by this European Standard:
a) this European Standard provides no information as to whether the product may be used without restriction in
any of the Member States of the EU or EFTA;
b) it should be noted that, while awaiting the adoption of verifiable European criteria, existing national regulations
concerning the use and/or the characteristics of this product remain in force.
NOTE Conformity with this European Standard does not confer or imply acceptance or approval of the products in any of
the Member States of the EU or EFTA. The use of the products covered by this European Standard is subject to regulation or
control by National Authorities.

1 Scope
This European Standard is applicable to calcium hypochlorite used for the treatment of water intended for human
consumption. It describes the characteristics of calcium hypochlorite and specifies the requirements and the
corresponding test methods for calcium hypochlorite. It provides information on its use in water treatment. It also
determines the rules relating to safe handling and use of calcium hypochlorite (see Annex B).
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 1483, Water quality - Determination of mercury - Method using atomic absorption spectrometry
EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987)
ISO 3165, Sampling of chemical products for industrial use - Safety in sampling
ISO 6206, Chemical products for industrial use - Sampling – Vocabulary
ISO 8213, Chemical products for industrial use - Sampling techniques - Solid chemical products in the form of
particles varying from powders to coarse lumps
ISO 8288, Water quality - Determination of cobalt, nickel, copper, zinc, cadmium and lead - Flame atomic
absorption spectrometric methods
ISO 9174, Water quality - Determination of chromium - Atomic absorption spectrometric methods
3 Description
3.1 Identification
3.1.1 Chemical name
Calcium hypochlorite.
3.1.2 Synonym or common name
None.
3.1.3 Relative molecular mass
142,99.
3.1.4 Empirical formula
Ca(ClO) .
3.1.5 Chemical formula
Ca(ClO) .
1)
3.1.6 CAS Registry Number
7778-54-3.
2)
3.1.7 EINECS reference
231-908-7.
3.2 Commercial form
The product is available as a granular solid or in the form of tablets.
3.3 Physical properties
3.3.1 Appearance
The product is white free-flowing granules or white tablets.
3.3.2 Density
3 3 3 3
The bulk density is approximately 0,8 g/cm to 1 g/cm for loose granular material and 1,2 g/cm to 1,3 g/cm for
3 3
tablets, while the density of one tablet is approximately 1,7 g/cm to 1,9 g/cm .
3.3.3 Solubility in water
The solubility is 180 g/l at 25 °C.
3.3.4 Vapour pressure
Not applicable.
3)
3.3.5 Boiling point at 100 kPa
Not applicable.
3.3.6 Melting point
Not applicable as the product decomposes at 177 °C.
3.3.7 Specific heat
Not known.
3.3.8 Viscosity, dynamic
Not applicable.
3.3.9 Critical temperature
Not applicable.
1)
Chemical Abstracts Service Registry Number.
2)
European Inventory of Existing Commercial Chemical Substances.
3)
100 kPa = 1 bar.
3.3.10 Critical pressure
Not applicable.
3.3.11 Physical hardness
Not applicable.
3.4 Chemical properties
Solutions of calcium hypochlorite are alkaline. The pH value of a solution of concentration 10 g/l is about 11,5 at
25 °C.
Calcium hypochlorite is a strong oxidant and chlorination agent. It reacts with acids or acidic salts to form chlorine,
and can form explosive nitrogen chlorides with ammonia and ammonia compounds. In the presence of inflammable
substances, it causes fires and explosions of organic compounds, oxidation reactions occur with the release of
heat and of moisture, and it is also highly corrosive to most metals.
4 Purity criteria
4.1 General
This European Standard specifies the minimum purity requirements for calcium hypochlorite used for the treatment
of water intended for human consumption. Limits are given for impurities commonly present in the product.
Depending on the raw material and the manufacturing process other impurities may be present and if so, then the
user, and when necessary the relevant authorities, shall be notified.
NOTE Users of the product should check the national regulations to clarify whether it is of appropriate purity for treatment
of water intended for human consumption, taking into account raw water quality, required dosage, contents of other impurities
and additives used in the product not stated in this product standard
Limits have been given for impurities and chemical parameters where these are likely to be present in significant
quantities from the current production process and raw materials. If in the production process or raw materials lead
to significant quantities of impurities, by-products or additives being present, this shall be notified to the user.
4.2 Composition of commercial product
The product shall contain a minimum of a mass fraction of 65,5 % of calcium hypochlorite (equivalent to an
available active chlorine content of at least a mass fraction of 65 %.
Dissolution quality, calculated as available chlorine which is obtainable within 1 min after dissolution in water, shall
not be less than a mass fraction of 45, 5 %.
NOTE The water content at the time of delivery should not exceed a mass fraction of 16 % of the product. As the test
method is usually not conducted by the user without danger of explosion, the manufacturer should guarantee to maintain this
value. If necessary a test laboratory can be requested to carry out this test. This determination should be carried out by
specialists only.
4.3 Impurities and main by-products
The sodium chloride content shall not exceed a mass fraction of 18 % of the product.
The content of water-insoluble matter shall not exceed a mass fraction of 6 % of the product.
NOTE 1 The water insoluble matter consists mainly of carbonates.
NOTE 2 Calcium chlorate can be present as a by-product of the production process.
4.4 Chemical parameters
The product shall conform to the requirements specified in Table 1.
Table 1 – Chemical parameters
Parameter Limit in mg/kg
of available chlorine
Type 1 Type 2
Arsenic (As) max. 5 10
Cadmium (Cd) max. 5 10
Chromium (Cr) max. 15 15
Mercury (Hg) max. 5 7
Nickel (Ni) max. 8 10
Lead (Pb) max. 15 15
Antimony (Sb) max. 15 15
Selenium (Se) max. 20 20
Limit in g/kg
of available chlorine
Bromate max. 2,1 4,2
a
Bromate is a by-product of the manufacturing process.
NOTE Cyanide, which does not exist in a strong oxidizing medium such
as calcium hypochlorite is not a relevant chemical parameters. Pesticides
and polycyclic aromatic hydrocarbons are not by-products of the
manufacturing process. For parametric values of calcium hypochlorite on
trace metal content in drinking water, see [1].
5 Test methods
5.1 Sampling
Observe the general recommendations of ISO 3165 and take account of ISO 6206. Prepare the laboratory
sample(s) required by the relevant procedure described in ISO 8213.
5.2 Analysis
5.2.1 Determination of calcium hypochlorite content (main product)
5.2.1.1 Principle
Calcium hypochlorite reacts with potassium iodide to release iodine in the presence of acetic acid. The iodine is
titrated with sodium thiosulfate standard volumetric solution in the presence of starch indicator solution.
NOTE 1 It detects all oxidizing agents being active in a weak acidic solution, i.e. hypochlorite/chlorine, iodate, and partially
chloramines, Fe(III), etc. Not covered under these conditions are bromate and chlorate.
NOTE 2 The titration can also be carried out potentiometrically by the aid of titration automates; the addition of soluble starch
is then unnecessary.
5.2.1.2 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3 specified in EN
ISO 3696.
5.2.1.2.1 Potassium iodide crystals (KI).
5.2.1.2.2 Glacial acetic acid.
5.2.1.2.3 Sodium thiosulfate standard volumetric solution, c(Na S O .5H O) = 0,1 mol/l.
2 2 3 2
Standard volumetric solutions are commercially available; eventually they have to be diluted.
Alternatively a standard volumetric solution can be prepared by the following procedure:
Dissolve 24,8 g Na S O . 5 H O in a 1 000 ml one-mark volumetric flask in about 0,75 l water. After the
2 2 3 2
temperature has equalized make up to the mark with water and mix thoroughly.
To standardize: Weigh, to the nearest 0,1 mg, 3,600 g (m) of dry potassium iodate. Dissolve in water in a 1 000 ml
one-mark volumetric flask, make up to the mark with water and mix (standard reference solution c(1/6 KIO ) = 0,1
mol/l ). Place 200 ml of water in a 500 ml stoppered conical flask, add (2 ± 0,5) g of potassium iodide and stir to
dissolve. Then introduce by means of a pipette, 10,0 ml of sodium thiosulfate solution for standardization , add (15
± 1) ml of hydrochloric acid solution (diluted 1 + 1 by volume) and (5 ± 1) ml of starch solution (5.2.1.2.4). Titrate
immediately with the potassium iodate standard reference solution until the appearance of a blue coloration
persisting for at least 30 s. Record the volume (V) of iodate used.
The concentration, c, of the sodium thiosulfate standard volumetric solution (Na S O .5H O), expressed in moles
2 2 3 2
per litre is given by the following equation:
m
c = (1)
V × 49,0317
where
m is the mass, in milligrams, of potassium iodate (KIO ) weighed;
V is the volume, in millilitres, of the sodium thiosulfate standard volumetric solution used.

5.2.1.2.4 Starch solution, mass fraction 1 %.
Make a slurry with (1 ± 0,1) g starch and (5 ± 1) ml water. Add (90 ± 5) ml boiling water to the slurry. Stir to dissolve
it and cool the solution. This solution needs refrigeration to avoid the decomposition of the starch which results in a
vague end point. Keep the solution cool and use it within one week.
NOTE Commercial indicators for iodine titration exist and can be used in place of the described starch solution provided
that their efficiency has been previously tested.
5.2.1.3 Apparatus
Ordinary laboratory apparatus and glassware, together with the following:
Laboratory sonic vibrator.
5.2.1.4 Procedure
5.2.1.4.1 Test portion
Weigh, to the nearest 0,1 mg, 3,5 g of the laboratory sample (m ) into a tarred stoppered weighing bottle.
5.2.1.4.2 Determination
Transfer the test portion to a 500 ml volumetric flask with 300 ml of water, stopper, and place in the sonic vibrator
for 10 min, swirling it occasionally until the test portion is in a solution. Make up to the mark with water.
Place a magnetic stirring bar into the volumetric flask and begin mixing. Transfer 25 ml, while the test portion is
being stirred and without allowing any insoluble matter to settle out, into the 500 ml conical flask.
Add 100 ml of water and 2 g of potassium iodide (5.2.1.2.1), and mix to dissolve. Add 8 ml of glacial acetic acid
(5.2.1.2.2), stir and titrate immediately with the sodium thiosulfate standard volumetric solution (5.2.1.2.3) to a light
yellow colour. Add 3 ml of the starch solution (5.2.1.2.4) and continue titration to the disappearance of the blue
black colour. Record the volume V , of the sodium thiosulfate standard volumetric solution used.
5.2.1.5 Expression of results
The chlorine (Cl ) content, C , expressed as a mass fraction in %, is given by the following equation:
2 1
V × c × 35,453× 20 × 100
C = (2)
m
where
V is the volume, in millilitres, of the sodium thiosulfate solution (5.2.1.2.3) used for the titration;
c is the concentration, in moles per litre, of the sodium thiosulfate standard volumetric solution
(5.2.1.2.3);
m is the mass, in milligrams, of the test portion (5.2.1.4.1);
35,453 is the mass in milligrams of chlorine (Cl ) corresponding to 1,00 ml of sodium thiosulfate solution
c(Na S O .5H O) = 1,000 mol/l.
2 2 3 2
The Ca(ClO) content, C , expressed as a mass fraction of product, is given by the following equation:
2 2
C × 3,5746
C = (3)
3,5453
5.2.1.6 Repeatability limit
The absolute difference between two single test results, obtained under repeatability conditions, shall not be
greater than the repeatability value, r, as calculated from the following equation:
r = 0,01 x z (4)
where
z is the mean of the two results, expressed in mass fraction in percent (%).
NOTE Repeatability conditions are conditions where mutually independent test results are obtained with the same method
on identical test material in the same laboratory by the same operator using the same equipment within short intervals of time.
5.2.2 Dissolution quality (available chlorine after 1 min)
5.2.2.1 Principle
A representative sample is stirred in water for 1 min and immediately titrated iodometrically. Dissolved calcium
hypochlorite reacts with iodide in the presence of acetic acidic to release iodine, which is titrated with sodium
thiosulfate standard volumetric solution.

NOTE The titration can be carried out manually with the addition of starch solution as a visual indicator, or
potentiometrically without an indicator by the aid of titration automates.
5.2.2.2 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3 specified in
EN ISO 3696.
5.2.2.2.1 Sodium thiosulfate standard volumetric solution, c(Na S O .5H O) = 0,1 mol/l (see 5.2.1.2.3).
2 2 3 2
5.2.2.2.2 Potassium iodide, virtually free of iodate.
5.2.2.2.3 Glacial acetic acid.
5.2.2.2.4 Starch indicator solution, mass fraction 1 % (see 5.2.1.2.4).
5.2.2.3 Apparatus
Ordinary laboratory apparatus and glassware.
5.2.2.4 Procedure
From a representative sample of the product weigh 1,5 g to the nearest 1 mg (m ). Add the test portion to a beaker
containing 1 000 ml of water (at a temperature of 20 °C to 25 °C) and by use of a magnetic stirrer agitate the
contents.
After 1 min stop the stirrer and remove a 25 ml aliquot by use of a pipette. Transfer to a conical flask containing
100 ml of water, add 2 g of potassium iodide crystals (5.2.2.2.2), 8 ml of acetic acid (5.2.2.2.3) and titrate the
liberated iodine with sodium thiosulfate standard volumetric solution (5.2.2.2.1) to a light yellow colour. Add 3 ml of
the starch indicator solution (5.2.2.2.4) and continue titration to the disappearance of the blue-black colour. Record
the volume (V ) of the sodium thiosulfate standard volumetric solution used.
5.2.2.5 Expression of results
The available chlorine which is released within 1 min,(C ), expressed as a mass fraction in % of product is given by
the following equation:
V x c x 35,453 x 40 x 100
C = (5)
m
where
c is the concentration in moles per litre of sodium thiosulfate standard volumetric solution (5.2.2.2.1);

V is the volume, in millilitres, of the sodium thiosulfate standard volumetric solution (5.2.2.2.1);
m is the mass, in milligrams, of the test portion;
35,453 is the mass in milligrams of chlorine (Cl2) corresponding to 1,00 ml of sodium thiosulfate standard
volumetric solution c(Na S O .5H O) = 1,000 mol/l.
2 2 3 2
5.2.2.6 Repeatability limit
The absolute difference between two single test results, obtained under repeatability conditions, shall not be
greater than the repeatability value, r, as calculated from the following equation:
r = 0,01 z (6)
where
z is the mean of the two results, expressed in mass fraction in percent (%).
NOTE Repeatability conditions are conditions where mutually independent test results are obtained with the same method
on identical test material in the same laboratory by the same operator using the same equipment within short intervals of time.
5.2.3 Impurities
5.2.3.1 Determination of sodium chloride
5.2.3.1.1 General
This method applies to products with sodium chloride contents in the range of the mass fraction of 15 % to 25 %.
5.2.3.1.2 Principle
Calcium hypochlorite is acidified, digested to remove all traces of available chlorine, and diluted to a known
volume. Sodium is analysed in solution by atomic absorption spectrometry.
5.2.3.1.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3 specified in
EN ISO 3696.
5.2.3.1.3.1 Hydrochloric acid, concentrated, HCl.
5.2.3.1.3.2 Sodium standard solution (1 000 µg/ml).
Weigh 2,542 1 g of sodium chloride that has been previously dried for 1 h at 110 °C. Dissolve in water and make
up to 1 l. Mix well.
5.2.3.1.3.3 Commercial iodide starch test paper.
NOTE Provided that its efficiency has been previously tested.
5.2.3.1.4 Apparatus
Ordinary laboratory apparatus and glassware, together with the following.
5.2.3.1.4.1 Atomic absorption spectrometer equipped with sodium hollow cathode lamp.
5.2.3.1.4.2 Hot plates.
5.2.3.1.4.3 Laboratory sonic vibrator.
5.2.3.1.5 Procedure
5.2.3.1.5.1 Test portion
Weigh, to the nearest 0,1 mg, 3,5 g of the laboratory sample (m into a tared stoppered weighing bottle.
)
5.2.3.1.5.2 Determination
Transfer the test portion to a 500 ml volumetric flask with 300 ml of water, stopper, and place in the sonic vibrator
(5.2.3.1.4.3) for 10 min, swirling occasionally until the sample is in the solution. Make up to the mark with water.
From the prepared solution, transfer accurately 25 ml to a 150 ml beaker.
Add 10 ml of the concentrated hydrochloric acid and place on a hot plate (5.2.3.1.4.2).
Boil to reduce the volume to 25 ml or, until the salt begins to precipitate, rinse the side of the beaker with water and
test for available chlorine using the iodide - starch test paper (5.2.3.1.3.3). If chlorine is still present add 50 ml of
water and reduce the volume again to 25 ml. Rinse the side of the beaker with water and test for available chlorine.
Repeat the procedure until available chlorine is not present, then cover the beaker and digest for 1 min, allow to
cool then transfer to a 100 ml volumetric flask and make up to the mark with water.
Measure the absorbance of the solution on the atomic absorption spectrometer (5.2.3.1.4.1) with sodium hollow
cathode lamp at a wavelength of 330,2 nm with slit setting at "4" using an air-acetylene flame.
5.2.3.1.5.3 Calibration
Accurately transfer from the sodium standard solution (5.2.3.1.3.2) 1,0 ml, 2,0 ml, 3,0 ml, 4,0 ml,
5,0 ml, 10,0 ml and 20,0 ml portions to a series of 100 ml volumetric flasks, make up each to the mark with water
and mix well. Prepare a calibration blank.
Measure the absorbance of each calibration solution as described in 5.2.3.1.5.2, and prepare a calibration graph.
5.2.3.1.6 Expression of results
The sodium chloride content, (C ), expressed as a mass fraction in % of product, is given by the following equation:
c × 100 × 20 × 2,5421
C = (7)
m × 10000
where
m is the mass, in grams, of the test portion;
c is the concentration, in micrograms per millilitre, of sodium in the test portion as determined from the
calibration graph.
5.2.3.1.7 Repeatability limit
The absolute difference between two single test results, obtained under repeatability conditions, shall not be
greater than the repeatability value, r, as calculated from the following equation:
r = 0,025 z (8)
where
z is the mean of the two results, expressed in % (m/m).
NOTE 1 A 98,3 % to 100,7 % recovery was obtained at Na content of mass fraction of 20 %.
NOTE 2 Repeatability conditions are conditions where mutually independent test results are obtained with the same method
on identical test material in the same laboratory by the same operator using the same equipment within short intervals of time.
5.2.3.2 Insoluble matter
5.2.3.2.1 Principle
A representative sample of calcium hypochlorite is dissolved into water. The insoluble matter is separated by
filtration then dried and weighed.
5.2.3.2.2 Apparatus
Ordinary laboratory apparatus and glassware together with the following:
5.2.3.2.2.1 Sintered glass crucible of porosity P40 (pores size between 16 µm to 40 µm).
5.2.3.3.2.2 Oven capable of being controlled at (105 ± 3) °C.
5.2.3.2.3 Procedure
Weigh approximately 10 g of the representative sample (m ) to the nearest ± 0,01 g and dissolve in 1 000 ml of
water by stirring for 30 min. Then filter the solution under vacuum through a dried and weighed glass filter
(5.2.3.2.2.1). After the filtration, wash the residue with 20 ml of water and remove excess water by filtering under
vacuum. Dry the residue at (105 ± 3) °C in the oven (5.2.3.2.2.2) until the mass remains constant and weigh it (m )
after cooling in a desiccator.
5.2.3.2.4 Expression of results
The insoluble matter expressed as a mass fraction in %, C in the product is given by the following equation:
m
C = × 100 (9)
m
where
m is the mass, in grams, of the residue;
m is the mass, in grams, of the test portion.
5.2.3.3 Water content
DANGER! If the product is overheated (see paragraph 6.5.3), a violent decomposition or explosion can
occur. This test shall only be carried out by experienced laboratory staff (usually by the manufacturing
company) and not by the end users.
The determination of the water content of calcium hypochlorite can be achieved, by drying a sample at temperature
between 105 °C and 110 °C until the mass of dried residue remains constant.
5.2.4 Chemical parameters
5.2.4.1 Determination of antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni) and
selenium (Se).
5.2.4.1.1 Principle
The elements arsenic, antimony, cadmium, chromium, lead, nickel and selenium are determined by atomic
absorption spectrometry.
5.2.4.1.2 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to the grade 2 specified in
EN ISO 3696.
5.2.4.1.2.1. Nitric acid, concentrated, density ρ = 1,42 g/ml.
5.2.4.1.2.2 Procedure
5.2.4.1.2.3 Test portion
Weigh, to the nearest 0,001 g, 10 g (m) of the laboratory sample into a 100 ml one-mark volumetric flask.
5.2.4.1.2.4 Test solution
Add 1 ml of nitric acid (5.2.4.1.2.1) to the test portion; dilute with a few millilitres of water and mix. Make up to
volume with water and homogenize.
5.2.4.1.2.5 Determination
Determine the content of elements in the test solution (5.2.4.1.2.4) in accordance with the following methods:
 Cd, Ni and Pb : In accordance with ISO 8288, Method A.
 Cr : In accordance with ISO 9174.
 As, Se and Sb : In accordance with the method given in Annex C.
These methods will give an interim result (y) expressed in milligrams per litre which needs to be converted to give
the final concentration according to the equation in 5.2.4.1.2.6.
5.2.4.1.2.6 Expression of results
From the interim result (y) determined (see 5.2.4.1.2.5), the content, C , of each element in the laboratory sample,
expressed in milligrams per kilogram of available chlorine is given by the following equation:
V 100
C = y× × (10)
m C
where
y is the interim result (5.2.4.1.2.5);
V is the volume, expressed in millilitres, of the test solutions (5.2.4.1.2.4) (= 100 ml);
m is the mass, expressed in grams, of the test portion;
C is the available chlorine content in mass fraction of product (5.2.1.5).
5.2.4.2 Determination of the mercury content (Hg)
5.2.4.2.1 Principle
The element mercury is determined by flameless atomic absorption spectrometry in accordance with EN 1483.
5.2.4.2.2 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to the grade 3 specified in
EN ISO 3696.
5.2.4.2.2.1 Potassium permanganate solution, c(KMnO ) = 50 g/l.
5.2.4.2.2.2 Sulfuric acid, concentrated, density ρ = 1,84 g/ml.
5.2.4.2.2.3 Hydroxylammonium chloride solution, c(NH OH.HCl) = 100 g/l.
5.2.4.2.2.4 Potassium dichromate solution, c(K Cr O ) = 4 g/l in 50 % (V/V) nitric acid solution.
2 2 7
5.2.4.2.3 Procedure
5.2.4.2.3.1 Test portion
Weigh, to the nearest 0,01 g, 10 g (m ) of the laboratory sample, into a glass beaker.
5.2.4.2.3.2 Test solution
Quantitatively transfer the test portion to a washing flask (e.g. Durand bottle), capacity 250 ml, the gas inlet of
which is made of a porous frit. Dilute the contents of the washing flask with water to obtain a total volume of 100 ml.
Transfer to a volumetric flask (solution A).
Accurately pipette 10 ml of the solution A. Transfer to a 250 ml conical flask and add 60 ml of water, 20 ml of a
potassium permanganate solution (5.2.4.2.2.1) and five 1 ml portions of sulfuric acid (5.2.4.2.2.2). Heat and keep
boiling for 10 min. Allow to cool. Dissolve the precipitate (MnO ) with hydroxylammonium chloride (5.2.4.2.2.3), add
5 ml of the potassium dichromate solution (5.2.4.2.2.4) and transfer to a 100 ml volumetric flask. Make up to the
mark with water and mix.
5.2.4.2.3.3 Determination
Proceed as described in EN 1483.
5.2.4.2.
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