ISO 13545:2000

INTERNATIONAL ISO
STANDARD 13545
First edition
2000-03-01
Lead sulfide concentrates — Determination
of lead content — EDTA titration method
after acid digestion
Concentrés sulfurés de plomb — Dosage du plomb — Méthode par titrage
à l'EDTA après digestion acide
Reference number
©
ISO 2000
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 � CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 734 10 79
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2000 – All rights reserved

Contents Page
Foreword.iv
1 Scope .1
2 Normative references .1
3 Principle.1
4 Reagents.2
5 Apparatus .4
6 Sampling.4
7 Procedure .5
8 Expression of results .7
9 Accuracy.8
10 Test report .10
Annex A (normative) Procedure for the preparation and determination of the mass of a predried test
portion.11
Annex B (normative) Flowchart of the procedure for the acceptance of analytical values for test
samples.13
Annex C (informative) Derivation of precision equations.14
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 13545 was prepared by Technical Committee ISO/TC 183, Copper, lead and zinc ores
and concentrates.
Annexes A and B form a normative part of this International Standard. Annex C is for information only.
iv © ISO 2000 – All rights reserved

INTERNATIONAL STANDARD ISO 13545:2000(E)
Lead sulfide concentrates — Determination of lead content —
EDTA titration method after acid digestion
WARNING — This International Standard may involve hazardous materials, operations and equipment. It is
the responsibility of the user of this International Standard to establish appropriate health and safety
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies a lead sulfate precipitation EDTA titrimetric method after acid decomposition for
determination of the lead content of lead sulfide concentrates.
The method is applicable to lead sulfide concentrates having lead content in the range 50 % (m/m)to 80%(m/m). The
method is not applicable to lead concentrates containing more than 1 % (m/m) of barium.
2 Normative references
The following normative documents contain certain provisions which, through reference in this text, constitute
provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of
these publications do not apply. However, parties to agreements based on this International Standard are
encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated
below. For undated references, the latest edition of the normative document referred to applies. Members of ISO
and IEC maintain registers of currently valid International Standards.
ISO 385-1:1984, Laboratory glassware — Burettes — Part 1: General requirements.
ISO 648:1977, Laboratory glassware — One-mark pipettes.
ISO 1042:1998, Laboratory glassware — One-mark volumetric flasks.
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods.
ISO 4787:1984, Laboratory glassware — Volumetric glassware — Methods for use and testing of capacity.
ISO 9599:1991, Copper, lead and zinc sulfide concentrates — Determination of hygroscopic moisture in the
analysis sample — Gravimetric method.
ISO Guide 35:1989, Certification of reference materials — General and statistical principles.
3Principle
Decomposition of the test portion in nitric and sulfuric acids and bromine, and removal of arsenic, antimony and tin
by hydrobromic acid treatment. Separation of lead from interfering elements by precipitation of lead sulfate.
Dissolution of the precipitate in an ammonium acetate solution. Titration of the solution with EDTA using xylenol
orange as the indicator.
4 Reagents
During the analysis, use only reagents of recognized analytical grade and water that complies with grade 2 of
ISO 3696.
4.1 Dilute hydrochloric acid (1+1)
To 500 ml of water slowly add 500 ml of hydrochloric acid (ρ 1,16 g/ml to 1,19 g/ml).
4.2 Nitric acid,ρ 1,42 g/ml
4.3 Dilute nitric acid, (1+3)
To 300 ml of water slowly add 100 ml of nitric acid (4.2).
4.4 Dilute nitric acid, (1+9)
To 450 ml of water slowly add 50 ml of nitric acid (4.2).
4.5 Perchloric acid,ρ 1,70 g/ml
4.6 Hydrofluoric acid,ρ 1,14 g/ml
4.7 Hydrobromic acid,ρ 1,50 g/ml
4.8 Dilute sulfuric acid,(1+1)
To 500 ml of water slowly add, with stirring and cooling, 500 ml of sulfuric acid (ρ 1,84 g/ml).
4.9 Dilute sulfuric acid, (1+99)
To 490 ml of water slowly add 10 ml of dilute sulfuric acid (4.8).
4.10 Dilute sulfuric acid washing solution
To 500 ml of sulfuric acid (4.9) add 50 ml of ethanol or methanol (4.21) and cool.
4.11 Nitration mixture
To 250 ml of nitric acid (4.2) slowly add, with stirring and cooling, 250 ml of sulfuric acid (ρ 1,84 g/ml).
4.12 Dilute ammonium hydroxide,(1+1)
To 500 ml of water slowly add 500 ml of ammonium hydroxide (ρ 0,90 g/ml).
4.13 Lead metal, minimum 99,99 % purity
The surface of the metal shall be free from oxide prior to use and may be cleaned by immersing the metal in nitric acid
(4.4)for1min, washing wellwith waterfollowedbyacetoneanddryinginanovenat50°C.
4.14 Bromine
4.15 Sodium chloride
4.16 Potassium chloride
4.17 Sodium peroxide
2 © ISO 2000 – All rights reserved

4.18 Fusion mixture, one part sodium carbonate mixed with one part potassium carbonate.
4.19 Ammonium acetate solution
Dissolve 250 g of ammonium acetate in water and dilute to 1 000 ml. Add 25 ml of acetic acid to the solution and mix.
4.20 Ammonium acetate washing solution
To 950 ml of water, add 50 ml of ammonium acetate solution (4.19).
4.21 Ethanol [99,5 % (V/V)] or methanol [99,5 % (V/V)].
4.22 L (+) - ascorbic acid
4.23 Iron(III) solution,(10mgFe/ml)
Dissolve 1 g of iron in 30 ml of dilute hydrochloric acid (4.1) by heating. Add 5 ml of nitric acid (4.2) to oxidize to
iron(III) ion, cool and dilute to 100 ml with water. This solution shall be used for matrix matching.
4.24 Zinc solution,(10 mg Zn/ml)
Dissolve 1 g of zinc [minimum purity 99,9 % and maximum lead content 0,001 % (m/m)] in 20 ml of dilute hydrochloric
acid (4.1) by heating, cool and dilute to 100 ml with water. This solution shall be used for matrix matching.
4.25 Lead standard solution,(0,1mgPb/ml)
Weigh 0,1 g of clean lead metal (4.13), accurately to the nearest 0,1 mg, transfer it to a 200 ml beaker and
decompose with 20 ml of dilute nitric acid (4.3). Heat to remove nitrogen oxides, cool to room temperature and add
about 50 ml of water. Transfer to a 1 000 ml volumetric flask and dilute to the mark with water.
4.26 Disodium ethylenediaminetetraacetic acid solution, (0,01 mol/l EDTA solution)
Dissolve 0,38 g of disodium ethylenediaminetetraacetate (dihydrate) in 100 ml of water. This solution is used for
titration of bismuth in the alternative titration described in 7.6.
4.27 Disodium ethylenediaminetetraacetic acid volumetric standard solution, (0,025 mol/l EDTA standard
solution).
4.27.1 Preparation
Dissolve 9,4 g of disodium ethylenediaminetetraacetate (dihydrate) in 1 000 ml of water; 1 ml of this solution
corresponds to about 5,2 mg of lead. Standardize by the procedure specified in 4.27.2.
4.27.2 Standardization
Accurately weigh three samples of clean lead metal (4.13), each of 200 mg, to the nearest 0,1 mg, and transfer them
to three 400 ml conical beakers. Record these masses as m , m and m .
1 2 3
NOTE The mass of lead metal should match the estimated mass of lead in the test portion.
Add 20 ml of dilute nitric acid (4.3), cover with a watch glass and heat to complete dissolution. After rinsing the
underside of the watch glass and inside of the conical beakers with water, boil gently to expel nitrogen oxides and
cool. Add 30 ml of ammonium acetate solution (4.19) and dilute the solution to about 150 ml with water. Adjust the pH
of the solution to a value between 5,5 and 5,7 with dilute ammonium hydroxide (4.12) using a pH meter (5.6).
Continue the standardization in accordance with the procedure specified in 7.6. Record the volume of EDTA standard
solution used in the titration as V , V and V .
1 2 3
Calculate the factors f , f and f using the following equation:
1 2 3
m m m
1 2 3
f��f f� (1)
1 2 3
V V V
1 2 3
Calculate, to four significant figures, the mean factor, f, for the EDTA standard solution provided that the range of the
values of f , f and f does not exceed 0,02 mg/ml. If this range is exceeded, repeat the standardization.
1 2 3
4.29 Xylenol orange solution,(1g/l)
Dissolve 0,1 g of xylenol orange in 100 ml of water.
5 Apparatus
Ordinary laboratory equipment and
5.1 Volumetric glassware, class A, complying with ISO 385-1, ISO 648, and ISO 1042 and used in accordance
with ISO 4787.
5.2 Analytical balance, sensitive to 0,1 mg.
5.3 Platinum crucibles or zirconium crucibles.
5.4 Atomic absorption spectrometer (AAS), with lead hollow cathode lamp.
Instrument conditions:
� flame – air/acetylene;
� wavelength – 217 or 283,3 nm.
5.5 ICP atomic emission spectrometer (ICP), optional.
5.6 pH meter.
6 Sampling
6.1 Test sample
Prepare an air-equilibrated test sample in accordance with ISO 9599.
NOTE An air-equilibrated test sample is not required if predried test portions are to be used (see annex A).
6.2 Test portion
Taking multiple increments, extract a mass of test portion from the test sample and weigh 0,25 g to 0,5 g to the
nearest 0,1 mg. The test portion weighed shall contain about 200 mg lead. At the same time as test portions are being
weighed for analysis, weigh test portions for the determination of hygroscopic moisture in accordance with ISO 9599.
Alternatively, the method specified in annex A may be used to prepare predried test portions directly from the
laboratory sample.
4 © ISO 2000 – All rights reserved

7 Procedure
7.1 Number of determinations
Carry out the determinations at least in duplicate, as far as possible under repeatab
...