SIST ISO 15247:2016

SLOVENSKI STANDARD
01-maj-2016
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SIST ISO 15247:2001
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Zinc sulfide concentrates - Determination of silver content - Acid dissolution and flame
atomic absorption spectrometric method
Concentrés sulfurés de zinc - Dosage de l'argent - Méthode par dissolution acide et
spectrométrie d'absorption atomique dans la flamme
Ta slovenski standard je istoveten z: ISO 15247:2015
ICS:
73.060.99 Druge rude Other metalliferous minerals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 15247
Second edition
2015-07-01
Corrected version
2015-09-15
Zinc sulfide concentrates —
Determination of silver content —
Acid dissolution and flame atomic
absorption spectrometric method
Concentrés sulfurés de zinc — Dosage de l’argent — Méthode par
dissolution acide et spectrométrie d’absorption atomique dans la
flamme
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 1
5 Apparatus . 2
6 Samples . 3
6.1 Test sample . 3
6.2 Test portion . 3
7 Procedure. 3
7.1 Number of determinations . 3
7.2 Blank test . 3
7.3 Decomposition of test portion . 3
7.4 Determination of silver . 4
8 Expression of results . 4
9 Precision . 5
9.1 Expression of precision . 5
9.2 Method for obtaining the final result (see Annex B) . 5
9.3 Precision between laboratories . 5
9.4 Check of trueness . 6
10 Test reports . 7
Annex A (normative) Procedure for the preparation and determination of the mass of a
predried test portion . 8
Annex B (normative) Flowsheet of the procedure for the acceptance of analytical values for
test samples .10
Annex C (informative) Derivation of precision equations .11
Bibliography .15
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 183, Copper, lead, zinc and nickel ores and
concentrates.
This second edition cancels and replaces the first edition (ISO 15247:1999), of which the warning in
A.3.1 in Annex A has been revised.
This corrected version of ISO 15247:2015 incorporates the following corrections:
— in 4.4, “hydrofluoric acid” has been changed to “hydrochloric acid”;
— in 9.1, in the definition of variables used in Formula (3), “s ” has been changed to “s ”.
R L
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 15247:2015(E)
Zinc sulfide concentrates — Determination of silver
content — Acid dissolution and flame atomic absorption
spectrometric method
1 Scope
This International Standard specifies an acid dissolution and flame atomic absorption spectrometric
method for the determination of silver content of zinc sulfide concentrates.
The method is applicable to the determination of silver in zinc sulfide concentrates containing up to
60 % (m/m) zinc in the form of zinc blende and related materials.
The method is applicable to silver contents from 10 g/t to 500 g/t.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods.
ISO 4787, Laboratory glassware — Volumetric instruments — Methods for testing of capacity and for use
ISO 9599, Copper, lead, zinc and nickel sulfide concentrates — Determination of hygroscopic moisture
content of the analysis sample — Gravimetric method
3 Principle
Decomposition of the concentrate in hydrochloric and nitric acids. Dissolution of the digestion residue
in hydrochloric acid and measurement by flame atomic absorption at 328,1 nm.
4 Reagents
During the analysis, use only reagents of recognized analytical grade and water that complies with
grade 2 of ISO 3696.
4.1 Silver metal, minimum 99,99 % purity.
4.2 Nitric acid, (ρ 1,42 g/ml), chloride content < 0,5 mg/ml.
4.3 Nitric acid, (500 ml/l).
To 250 ml of water carefully add, with stirring, 250 ml of nitric acid (4.2).
4.4 Hydrochloric acid, (ρ 1,16 g/ml to 1,19 g/ml).
4.5 Hydrochloric acid, (200 ml/l).
To 800 ml of water carefully add, with stirring, 200 ml of hydrochloric acid (4.4).
4.6 Ammonia solution, (ρ 0,89 g/ml).
4.7 Ammonia solution, (250 ml/l).
To 750 ml of water add, with stirring, 250 ml of ammonia solution (4.6).
4.8 Silver standard solutions
4.8.1 Silver standard solution, (1 000 μg/ml).
Weigh 0,500 0 g of silver metal (4.1) into a 250 ml conical beaker, add 50 ml of nitric acid (4.3), cover,
and heat gently until the metal dissolves. Remove the cover and evaporate gently to near dryness. Add
250 ml of hydrochloric acid (4.4) and warm until the solution clears. Cool, and transfer to a 500 ml
volumetric flask. Dilute to volume with water and mix thoroughly.
This solution should be freshly prepared, unless it is being used on a regular basis.
4.8.2 Silver standard solution, (100 μg/ml).
Pipette 10 ml of silver standard solution (4.8.1) into a 100 ml volumetric flask containing 45 ml of
hydrochloric acid (4.4). Dilute to volume with water and mix thoroughly.
Standard solutions should be prepared at the same ambient temperature as that at which the
determinations will be conducted.
Silver standard solutions should be stored in brown glass bottles.
4.9 Calibration solutions
To six 100 ml volumetric flasks, each containing 20 ml of hydrochloric acid (4.4), add from a burette
(5.2) 0 ml, 1 ml, 2 ml, 3 ml, 4 ml, and 5 ml of silver standard solution (4.8.2). Dilute to volume with water
and mix thoroughly.
These standards contain 0 μg, 1 μg, 2 μg, 3 μg, 4 μg, and 5 μg of silver per ml and shall be freshly prepared.
Calibration solutions should be prepared at the same ambient temperature as that at which the
determinations will be conducted.
5 Apparatus
Ordinary laboratory apparatus and the following.
5.1 Volumetric glassware, of class A complying with ISO 385, ISO 648, and ISO 1042 and used in
accordance with ISO 4787.
5.2 Burette, grade A 10 ml capacity, capable of being read to 0,02 ml.
5.3 Atomic absorption spectrometer (AAS), equipped with a glass bead in the spray chamber rather
than a flow spoiler.
5.4 Balance, precision analytical, capable of being read to 0,1 mg.
2 © ISO 2015 – All rights reserved

6 Samples
6.1 Test sample
Prepare an air-equilibrated test sample in accordance with ISO 9599.
NOTE A 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 test portion from the test sample in such a manner that it is
representative of the whole contents of the dish or tray. Weigh to the nearest 0,1 mg approximately 1 g
of test sample. At the same time as the test portion is weighed, weigh test portions for the determination
of hygroscopic moisture in accordance with ISO 9599.
Alternatively, the method specified in Annex A can be used to prepare predried test portions directly
from the laboratory sample.
7 Procedure
7.1 Number of determinations
Carry out the determinations at least in duplicate and as far as possible under repeatability conditions
on each test sample.
NOTE Repeatability conditions exist 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.
7.2 Blank test
Carry out a blank test in parallel with the analysis using all reagents specified in the determination
but omitting the test portion. The purpose of the blank te
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