ISO 10469:2006

INTERNATIONAL ISO
STANDARD 10469
Second edition
2006-07-01


Copper sulfide concentrates —
Determination of copper —
Electrogravimetric method
Concentrés de sulfure de cuivre — Dosage du cuivre — Méthode
électrogravimétrique





Reference number
ISO 10469:2006(E)
©
ISO 2006

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ISO 10469:2006(E)
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ISO 10469:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Principle. 1
4 Reagents. 2
5 Apparatus . 4
6 Sample . 5
6.1 Test sample . 5
6.2 Test portion . 5
7 Procedure . 5
7.1 Number of determinations . 5
7.2 Blank test. 5
7.3 Dissolution of test portion . 5
7.4 Separation of arsenic, antimony, tin, selenium and silver . 5
7.5 Copper separation . 6
7.5.1 Sulfide separation. 6
7.5.2 Hydroxide separation . 7
7.6 Electrolytic deposition . 7
7.7 FAAS determination of copper in the electrolyte, filter residues and sulfide precipitates. 8
7.7.1 FAAS determination of copper in the filtrate of the sulfide precipitation. 8
7.7.2 Treatment of hydroxide precipitate in sulfide separation . 8
7.7.3 FAAS determination of copper in the electrolyte, filter residues and precipitates (sulfide
separation method). 8
7.8 FAAS determination of copper in the electrolyte, filter residues and precipitates
(hydroxide separation method). 9
8 Expression of results . 10
9 Precision. 10
9.1 Expression of precision . 10
9.2 Method for obtaining the final result (see Annex B) . 10
9.3 Precision between laboratories. 11
9.4 Check of trueness. 11
9.4.1 Type of certified reference material (CRM) or reference material (RM) . 12
10 Test report . 12
Annex A (normative) Procedure for the preparation and determination of the mass of a predried
test portion . 13
Annex B (normative) Flowsheet of the procedure for the acceptance of analytical values for test
samples. 15
Annex C (informative) Derivation of precision equations. 16

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ISO 10469:2006(E)
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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 10469 was prepared by Technical Committee ISO/TC 183, Copper, lead, zinc and nickel ores and
concentrates.
This second edition cancels and replaces the first edition (ISO 10469:1994), which has been technically
revised.
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ISO 10469:2006(E)
Introduction
ISO 10469:1994 underwent periodical review in 1999. Although the decision was made to confirm the
International Standard at that time, significant comments were submitted by Japan. These comments were
considered at a meeting of ISO/TC 183 in 2000, where it was agreed that Japan would re-draft ISO 10469 to
indicate the proposed changes.
The most significant change was the elimination of the correction for impurities.
ISO/TC 183 agreed that the changes made do not warrant a new interlaboratory test programme. Details of
the changes are as follows:
a) Deletion of the determination of impurities in the deposited copper (7.9 in ISO 10469:1994).
b) Adjustment of the expression of dissolution of the test portion according to ISO 10258:1994, Copper
sulfide concentrates — Determination of copper content — Titrimetric methods.
c) Adjustment of the expression of the sulfide separation method according to ISO 10258:1994.
d) In the case of contained bismuth or tellurium, modification of the sulfide separation procedure. The
method described in ISO 10469:1994 included a lot of copper in the iron hydroxide precipitation, which
will lead to incorrect results. The method described in ISO 13658:2000, Zinc sulfide concentrates —
Determination of zinc content — Hydroxide precipitation and EDTA titrimetric method has less copper in
the iron hydroxide precipitation than the method described in ISO 10469:1994, so the method described
in ISO 10469:1994 has now been modified with reference to ISO 13658.
e) The procedure of treatment of the iron hydroxide precipitation (contained copper) is not given in
ISO 10469:1994. The procedure of treatment has been added to the revised Standard.
Calibration solution A (4.34.1 in ISO 10469:1994) will be used in 7.7.1 (FAAS determination of copper in the
filtrate of the sulfide precipitation). This filtrate contains iron ion, so calibration solution A should contain iron to
achieve matrix matching. The preparation method of calibration solution A has been revised to include iron ion
in the revised Standard.

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INTERNATIONAL STANDARD ISO 10469:2006(E)

Copper sulfide concentrates — Determination of copper —
Electrogravimetric method
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 an electrogravimetric method for the determination of the mass fraction
of copper in copper sulfide concentrates in the range 15 % to 50 %.
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.
ISO 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — One-mark pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 4787, Laboratory glassware — Volumetric glassware — Methods for use and testing of capacity
ISO 9599, Copper, lead and zinc sulfide concentrates — Determination of hygroscopic moisture in the
analysis sample — Gravimetric method
3 Principle
The test portion is decomposed in nitric and sulfuric acids, and copper is separated from interfering elements:
⎯ from silver by precipitation of silver chloride;
⎯ from arsenic, antimony, selenium and tin by fuming with hydrobromic acid;
⎯ from iron by precipitation of copper sulfide with sodium thiosulfate or by precipitation of iron(III) oxide
hydrate (bismuth and tellurium are also separated in this way).
Electrogravimetric deposition of copper occurs in the presence of nitric acid, sulfuric acid and traces of
chloride. Under these conditions, coprecipitation of molybdenum does not occur.
Traces of copper in the electrolyte, the filtrate of the copper sulfide precipitation, all precipitates and residues
are determined by flame atomic absorption spectrometry (FAAS) or inductively coupled plasma atomic
emission spectrometry.
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ISO 10469:2006(E)
The normal mass fraction of mercury in copper concentrates does not usually affect the copper result. At a
level of 0,005 % or greater, the mass fraction of mercury in the copper deposit should be checked. This
procedure is not described in this International Standard.
4 Reagents
During the analysis, use only reagents of recognized analytical grade and distilled water or water of equivalent
purity.
4.1 Nitric acid, concentrated (ρ 1,42 g/ml).
20
4.2 Nitric acid, diluted 1 + 1.
Slowly add 500 ml of concentrated nitric acid (4.1) to 500 ml of water, while stirring.
4.3 Sulfuric acid, concentrated (ρ 1,84 g/ml).
20
4.4 Sulfuric acid, diluted 1 + 1.
Slowly add 500 ml of concentrated sulfuric acid (4.3) to 500 ml of water, while stirring. Cool the solution.
4.5 Sulfuric acid, diluted 1 + 4.
Slowly add 200 ml of concentrated sulfuric acid (4.3) to 800 ml of water, while stirring. Cool the solution.
4.6 Sodium thiosulfate pentahydrate, (450 g/l) solution.
4.7 Nitration mixture.
Slowly add 250 ml of concentrated sulfuric acid (4.3) to 250 ml of concentrated nitric acid (4.1).
4.8 Sodium chloride, 10 g/l solution.
4.9 Sodium chloride, 0,5 g/l solution.
4.10 2-propanol.
4.11 Ethanol, minimum purity 95 % (V/V).
4.12 Methanol, minimum purity 95 % (V/V).
4.13 Ammonium iron(III) sulfate solution.
Add 50 ml of dilute sulfuric acid (4.4) and 43 g of ammonium iron(III) sulfate dodecahydrate
[NH Fe(SO ) ·12H O] to 950 ml of water.
4 4 2 2
4.14 Iron(III) nitrate solution.
Add 30 g of iron(III) nitrate nonahydrate [Fe(NO ) ·9H O] to 100 ml of water.
3 3 2
4.15 Ammonia solution (ρ 0,91 g/ml).
20
4.16 Ammonia solution, diluted 1 + 99.
4.17 Hydrobromic acid (ρ 1,50 g/ml).
20
4.18 Perchloric acid (ρ 1,53 g/ml).
20
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ISO 10469:2006(E)
4.19 Hydrofluoric acid (ρ 1,14 g/ml).
20
4.20 Copper metal, minimum purity 99,999 %.
4.21 Sodium sulfate (Na SO ), anhydrous.
2 4
4.22 Hydrochloric acid, concentrated (ρ 1,16 g/ml to 1,18 g/ml).
20
4.23 Hydrochloric acid, diluted 1 + 1.
Slowly add 500 ml of concentrated hydrochloric acid (4.22) to 500 ml of water, while stirring.
4.24 Bromine.
4.25 Copper standard solution, 1 ml contains 0,1 mg of Cu.
Dissolve 0,1 000 g of copper metal (4.20) in 10 ml of warm dilute nitric acid (4.2) and heat to evaporate to
approximately 5 ml to remove nitrogen oxides. Transfer to a 1 000 ml volumetric flask, fill up nearly to the
mark with water, mix and equilibrate at room temperature; then fill up exactly to the mark and mix again.
Standard solutions should be prepared at the same ambient temperature as that at which the determinations
will be conducted.
4.26 Calibration solutions.
Calibration solutions should be prepared at the same ambient temperature as that at which the determination
will be conducted.
Calibration solutions should be prepared freshly before use.
4.26.1 Calibration solutions A.
Pipette 0,0 ml, 10,00 ml, 20,00 ml, 30,00 ml and 40,00 ml of copper standard solution (4.25) into a series of
500 ml one-mark volumetric flasks. Add 40 ml of dilute sulfuric acid (4.4), 13 g of sodium sulfate (4.21) and
50 ml (see third paragraph) of ammonium iron(III) sulfate (4.13) (corresponding to approximately 250 mg of
iron) to each flask. Dilute with water, stir to dissolve the salts, fill up nearly to the mark, mix and equilibrate at
room temperature, then fill up exactly to the mark and mix again.
These solutions contain 0 mg of Cu, 1 mg of Cu, 2 mg of Cu, 3 mg of Cu and 4 mg of Cu in a 500 ml volume.
If the test solution contains less than 50 mg of iron, only 10 ml of ammonium iron(III) sulfate (4.13) should be
added to each flask.
In situations where the test solution contains more than 4 mg of Cu, dilute with the calibration solution
containing 0,0 mg of Cu, until the copper concentration in the test solution is below 4 mg/500 ml.
4.26.2 Calibration solutions B.
Pipette 0,0 ml, 10,00 ml, 20,00 ml, 30,00 ml and 40,00 ml of copper standard solution (4.25) into a series of
500 ml one-mark volumetric flasks. Add 30 ml of dilute sulfuric acid (4.4), 10 ml of dilute nitric acid (4.2), 15 ml
of dilute hydrochloric acid (4.23) and 25 ml of ammonium iron(III) sulfate solution (4.13) to each flask. Fill up
nearly to the mark with water, mix and equilibrate at room temperature; then fill up exactly to the mark and mix
again.
These solutions contain 0 mg of Cu, 1 mg of Cu, 2 mg of Cu, 3 mg of Cu and 4 mg of Cu in a 500 ml volume.
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ISO 10469:2006(E)
In situations where the test solution contains more than 4 mg of Cu, dilute with the calibration solution
containing 0,0 mg of Cu, until the copper concentration in the test solution is below 4 mg/500 ml.
4.26.3 Calibration solutions C.
Pipette 0,0 ml, 10,00 ml, 20,00 ml, 30,00 ml and 40,00 ml of copper standard solution (4.25) into a series of
500 ml one-mark volumetric flasks. Add 20 ml of dilute sulfuric acid (4.4), 10 ml of dilute nitric acid (4.2) and
50 ml (see third pargraph) of ammonium iron(III) sulfate solution (4.13) (corresponding to approximately
250 mg of Fe) to each flask. Fill up nearly to the mark with water, mix and equilibrate at room temperature;
then fill up exactly to the mark and mix again.
These solutions contain 0 mg of Cu, 1 mg of Cu, 2 mg of Cu, 3 mg of Cu and 4 mg of Cu in a 500 ml volume.
If the test portion contains less than 50 mg of Fe [< 2,5 % (m/m) Fe], only 10 ml of ammonium iron(III) sulfate
solution (4.13) should be added each time.
In situations where the test solution contains more than 4 mg of Cu, dilute with the calibration solution
containing 0,0 mg of Cu, until the copper concentration in the test solution is below 4 mg/500 ml.
5 Apparatus
5.1 Usual laboratory equipment, including fume hoods, hotplates, a drying oven, an analytical balance
and a water bath with a thermostat for the temperature control of solutions.
5.2 Ordinary laboratory glassware.
5.3 Volumetric glassware, class A, complying with ISO 385, ISO 648 and ISO 1042, and used in
accordance with ISO 4787.
5.4 Desiccator.
5.5 Filter papers, of different porosity (dense and medium).
5.6 Equipment for static electrolysis.
5.7 Platinum electrodes, net electrodes as cathodes; spiral electrodes as anodes.
NOTE Winkler electrodes have been found suitable.
5.8 Atomic absorption spectrometer (AAS).
Instrument conditions:
Flame: air/acetylene
Wavelength 324,7 nm
5.9 Inductively coupled plasma (ICP) atomic emission spectrometer (optional).
5.10 Platinum dish.
5.11 Polytetrafluoroethylene (PTFE) dish.
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ISO 10469:2006(E)
6 Sample
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 approximately 2 g from the test sample and weigh to the nearest 0,1 mg
(m). 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.
7 Procedure
7.1 Number of determinations
Carry out the determinations at least in duplicate, 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 the same quantities of all reagents but omitting the
test portion. The purpose of the blank test in this method is to check the quality of reagents. If a significant
value is obtained as a result of the blank test, check all reagents and rectify the problem.
7.3 Dissolution of test portion
Transfer the test portion into a 400 ml or 500 ml conical or tall-form beaker, or a 500 ml Erlenmeyer flask.
Moisten with 10 ml of water. Add 20 ml of dilute nitric acid (4.2), cover the beaker with a watch glass or, if
using an Erlenmeyer flask, with a drip catcher and heat for about 10 min at 60 °C to 70 °C. Add 40 ml of dilute
sulfuric acid (4.4) and heat gradually to decompose the test portion. After completion of the initial reaction,
rinse the underside of the watch glass or drip catcher with a minimum volume of water, collecting the
washings in the conical beaker or Erlenmeyer flask. Continue heating until strong white fumes are evolved,
then cool.
If the residue appears dark (presence of carbon), slowly add a small amount of nitration mixture (4.7) to the
hot solution until the solution becomes colourless or bluish, then heat until strong white fumes are evolved.
If decomposition of the deposited sulfur is insufficient, add 5 ml of nitric acid (4.1) and 1 ml of bromine (4.24)
and heat until strong white fumes are evolved.
7.4 Separation of arsenic, antimony, tin, selenium and silver
Carefully add 5 ml of water and 10 ml of hydrobromic acid (4.17), heat until strong white fumes are evolved,
then cool. Add 5 ml of dilute sulfuric acid (4.4) and 10 ml of hydrobromic acid (4.17) and heat until strong white
fumes are evolved, then cool.
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ISO 10469:2006(E)
WARNING — Extreme caution MUST be taken during this step.
NOTE This step may be omitted if the test sample contains less than 0,01 % (m/m) each of As, Sb, Sn and Se.
Add 100 ml of water and warm to dissolve soluble salts.
Precipitate silver completely as silver chloride by adding approximately 1 ml of sodium chloride solution (4.8).
NOTE This step may be omitted if the test sample contains less than 0,01 % (m/m) of Ag.
Heat until boiling, then allow to cool.
Filter through a dense filter paper (5.5), wash with cold water and collect the filtrate in a 400 ml or 500 ml
conical or tall-form beaker, or a 500 ml Erlenmeyer flask (only for sulfide separation). Reserve the filter paper
and residue for the determination of copper by FAAS (as described in 7.7.3), unless it has been proven by
previous testing that the copper in the sample is completely soluble using the initial dissolution (7.3).
7.5 Copper separation
Separate copper from interfering ions in accordance with 7.5.1 or 7.5.2.
7.5.1 Sulfide separation
Dilute the filtrate to 200 ml with water and heat to 70 °C to 90 °C. Slowly add 50 ml of sodium thiosulfate
solution (4.6) while stirring, to produce a yellow or yellowish-brown emulsion. Heat gradually and continue
boiling gently until the precipitate coagulates.
Filter off the precipitate using a filter paper of medium porosity (5.5). Collect the filtrate in a 500 ml volumetric
flask, and immediately wash the filter and precipitate with hot water. Reserve the filtrate for the determination
of copper by FAAS (as described in 7.7.1).
Put the filter and copper sulfide precipitate back into the vessel used for precipitation, cover with a watch glass
or drip catcher, add 30 ml of nitric acid (4.1) and 10 ml of sulfuric acid (4.3), heat to decompose the precipitate
and filter paper, and continue heating until strong white fumes are evolved.
If the residue appears dark (presence of carbon), slowly add a small amount of nitration mixture (4.7) to the
hot solution until the residue becomes colourless or bluish.
Should elemental sulfur be present, continue heating strongly to destroy any elemental sulfur. Add 10 ml of
nitric acid (4.1) around the top of the beaker to rinse away the residual sulfur. Then add 2 ml of dilute sulfuric
acid (4.5) and heat until strong white fumes are evolved. Allow to cool.
Dilute with water to approximately 100 ml, warm to dissolve the soluble salts, filter into a 400 ml tall-form
beaker and wash the filter and vessel with water. Reserve the filter for the determination of copper by FAAS
(as described in 7.7.3).
NOTE The following step may be omitted if the test sample contains less than 0,01 % (m/m) of Bi and/or Te.
Add 3 ml of iron(III) nitrate solution (4.14) and slowly add ammonia solution (4.15) while stirring, until the basic
copper salt precipitated at first is dissolved again, then add a further 30 ml of ammonia solution (4.15) to make
the solution alkaline. Heat until the onset of boiling, filter the precipitate using a filter paper of medium porosity
(5.5) and wash with dilute ammonia solution (4.16). Collect the filtrate and washings in a 400 ml tall-form
beaker.
Rinse the precipitate back into the original beaker with water and dissolve any precipitate adhering to the filter
paper using 15 ml of warm dilute sulfuric acid (4.5) in small amounts. Wash the filter paper with warm water,
collecting the washings in the original beaker. Dissolve the precipitate completely by adding 10 ml of dilute
sulfuric acid (4.4), warm gently and dilute with water to obtain a volume of approximately 100 ml. Add
ammonia solution (4.15) while stirring, until a slight precipitate of iron(III) hydroxide appears, then add a
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ISO 10469:2006(E)
further 30 ml of ammonia solution in excess. Heat until the onset of boiling, filter using the same filter paper
again, wash with warm dilute ammonia solution (4.16) and collect the filtrate and washings in the 400 ml
tall-form beaker already used.
Add dilute sulfuric acid (4.4) to make the solution slightly acidic, then heat to evaporate the filtrate to a volume
of approximately 250 ml. Reserve the beaker and precipitate for the determination of copper by FAAS (as
described in 7.7.2).
Add 20 ml of dilute nitric acid (4.2) and 10 ml of sodium chloride solution (4.9), and dilute with water to
approximately 300 ml. Use this solution for the electrolytic deposition of copper (as described in 7.6).
7.5.2 Hydroxide separation
Bring the filtrate retained in 7.4 to a volume of 150 ml, either by dilution with water or evaporation by heating.
Slowly add ammonia solution (4.15) while stirring, until the basic copper salt precipitated at first is dissolved
again. Then add a further 30 ml of ammonia solution (4.15) in excess. Heat until the onset of boiling, filter
using a filter paper of medium porosity (5.5), wash with warm diluted ammonia solution (4.16) and collect the
filtrate and washing solutions in a 600 ml beaker.
If the test portion contains less than 50 mg of Fe [i.e. < 2,5 % (m/m) Fe]. add 10 ml of ammonium iron(III)
sulfate solution (4.13) (equivalent to approximately 50 mg of iron) before the precipitation of iron(III) hydroxide.
Rinse the precipitate back into the original beaker with water and dissolve any precipitate adhering to the filter
paper using 15 ml of warm dilute sulfuric acid (4.5) in small amounts. Wash the filter paper with warm water,
collecting the washings in the original beaker. Dissolve the precipitate completely by adding 10 ml of dilute
sulfuric acid (4.4), warm gently and dilute with water to obtain a volume of approximately 100 ml.
Add ammonia solution (4.15) while stirring, until a slight precipitate of iron(III) hydroxide appears, then add a
further 30 ml of ammonia solution (4.15) in excess.
Heat until the onset of boiling, filter using the same filter paper again, wash with warm dilute ammonia solution
(4.16) and collect the filtrate and washings in the 600 ml beaker already used. Reserve the precipitate and
beaker for the determination of copper by FAAS (as described in 7.8).
Heat to evaporate the filtrate to a volume of approximately 250 ml.
2+
NOTE The dark blue colour of the complex ion [(Cu(NH ) )] should disappear.
3 4
Add 20 ml of dilute sulfuric acid (4.4), 20 ml of dilute nitric acid (4.2) and 10 ml of sodium chloride solution
(4.9). Use this solution for the electrolytic deposition of copper (as described in 7.6)
...