SIST ISO 10258:2016

INTERNATIONAL ISO
STANDARD 10258
Second edition
2015-07-01
Copper sulfide concentrates —
Determination of copper content —
Titrimetric methods
Concentrés de sulfure de cuivre — Dosage du cuivre — Méthodes
titrimétriques
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
3.1 Method 1 (Long iodide method) . 1
3.2 Method 2 (Short iodide method). 1
4 Reagents . 1
5 Apparatus . 3
6 Sample . 4
6.1 Test sample . 4
6.2 Test portion . 4
7 Procedure. 4
7.1 Number of determinations . 4
7.2 Blank test . 4
7.3 Determination — method 1: Long iodide method . 5
7.3.1 Decomposition of test portion . 5
7.3.2 Separation of copper . 5
7.3.3 Dissolution of copper precipitate . 5
7.3.4 Titration. 6
7.3.5 FAAS determination of copper in the insoluble residue, filtrate, and filter paper . 6
7.4 Determination — method 2: Short iodide method . 7
7.4.1 Decomposition of the test portion . 7
7.4.2 Titration. 7
8 Expression of results . 8
9 Precision . 8
9.1 Expression of precision . 8
9.2 Method for obtaining the final result (see Annex B) . 9
9.3 Precision between laboratories . 9
9.4 Check of trueness .10
10 Test report .11
Annex A (normative) Procedure for the preparation and determination of the mass of a
predried test portion .12
Annex B (informative) Flowsheet of the procedure for the acceptance of analytical values
for test samples .14
Annex C (informative) Derivation of precision formulae .15
Bibliography .20
Foreword
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electrotechnical standardization.
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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
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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 10258:1994), of which the warning in
A.3.1 in Annex A has been revised.
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 10258:2015(E)
Copper sulfide concentrates — Determination of copper
content — Titrimetric methods
1 Scope
This International Standard specifies two titrimetric methods for the determination of the copper
content of copper sulfide concentrates in the range 15 % (m/m) to 50 % (m/m), using sodium thiosulfate
after separation (method 1) or without separation (method 2) of copper from interfering elements.
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 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
3.1 Method 1 (Long iodide method)
A test portion is decomposed in nitric and sulfuric acids, and arsenic, antimony, and tin are removed
by treatment with hydrobromic acid. Copper is separated from interfering elements by precipitation
of copper sulfide with sodium thiosulfate. The precipitate is dissolved in nitric and sulfuric acids,
ammonium hydrogen difluoride is added to eliminate interference of residual iron, and excess potassium
iodide is also added. Free iodine isolated by reaction between iodide ions and copper(II) ions is titrated
with sodium thiosulfate using soluble starch as the indicator.
3.2 Method 2 (Short iodide method)
A test portion is decomposed in nitric and sulfuric acids, and arsenic, antimony, and tin are removed by
treatment with hydrobromic acid. Ammonium hydrogen difluoride is added to eliminate interference of
iron, and excess potassium iodide is also added. Free iodine isolated by reaction between iodide ions and
copper(II) ions is titrated with sodium thiosulfate using soluble starch as the indicator.
4 Reagents
During the analysis, use only reagents of recognized analytical grade and distilled water or water of
equivalent purity.
4.1 Copper metal, minimum purity 99,99 %.
4.2 Potassium iodide.
4.3 Ammonium hydrogen difluoride.
4.4 Sulfuric acid, diluted 1 + 1.
Slowly add 500 ml of concentrated sulfuric acid (ρ 1,84 g/ml) to 500 ml of water, while stirring and cooling.
4.5 Sulfuric acid, diluted 1 + 999.
Add 1 ml of dilute sulfuric acid (4.4) to 500 ml of water.
4.6 Nitrit acid, concentrated (ρ 1,42 g/ml).
4.7 Nitrit acid, diluted 1 + 1.
Slowly add 500 ml of concentrated nitric acid (4.6) to 500 ml of water.
4.8 Hydrofluoric acid (ρ 1,14 g/ml).
4.9 Bromine.
4.10 Bromine water, saturated.
4.11 Hydrobromic acid (ρ 1,50 g/ml).
4.12 Acetic acid, diluted 1 + 3.
Slowly add 25 ml of glacial acetic (ρ 1,05 g/ml) to 75 ml of water.
4.13 Nitration mixture.
Slowly add 250 ml of concentrated sulfuric acid (ρ 1,84 g/ml) to 250 ml of concentrated nitric acid (4.6).
4.14 Ammonium hydrogen difluoride, 250 g/l solution.
4.15 Sodium carbonate, 20 g/l solution.
4.16 Sodium thiosulfate pentahydrate, 200 g/l solution.
4.17 Potassium thiocyanate, 100 g/l solution.
4.18 Starch, 2 g/l solution.
Moisten 1 g of soluble starch with cold water, slowly pour into 500 ml of hot water while stirring, and
boil for about 1 min.
4.19 Ethanol.
4.20 Standard solutions.
Standard solutions should be prepared at the same ambient temperature as that at which the
determinations will be conducted.
2 © ISO 2015 – All rights reserved

4.20.1 Sodium thiosulfate, standard volumetric solution (20 g/l).
4.20.1.1 Preparation
Dissolve 20 g of sodium thiosulfate (pentahydrate) in 1 l of freshly boiled and cooled water. Add 0,2 g of
sodium carbonate, stir to dissolve and allow to stand for at least one day. Standardize this solution as
specified in 4.20.1.2.
4.20.1.2 Standardization
Clean a piece of copper metal (4.1) by immersing it in warm dilute acetic acid (4.12). Wash the copper
thoroughly with water followed by ethanol (4.19) and allow to dry in air. Weigh into three separate
400 ml conical beakers to the nearest 0,1 mg, a mass of clean copper metal which approximates the
copper content in the test portion. Record these masses as m , m , and m .
1 2 3
Dissolve the copper using 10 ml of dilute nitric aci
...