ISO 23156:2021

INTERNATIONAL ISO
STANDARD 23156
First edition
2021-03
Ferronickels — Determination of
phosphorus, manganese, chromium,
copper and cobalt contents —
Inductively coupled plasma optical
emission spectrometric method
Ferro-nickels — Détermination du phosphore, du manganèse,
du chrome, du cuivre et du cobalt — Méthode par spectrométrie
d'émission optique avec plasma induit par haute fréquence
Reference number
ISO 23156:2021(E)
©
ISO 2021

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ISO 23156:2021(E)

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ISO 23156:2021(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 4
6.1 General . 4
6.2 Instrument performance requirements . 4
6.2.1 Wavelengths . 4
6.2.2 Practical resolution of the spectrometer . 5
6.2.3 Short-term stability . 5
6.2.4 Background equivalent concentration . 5
6.2.5 Linearity of the calibration curves . 5
7 Sampling and sample preparation . 5
8 Procedure. 5
8.1 Test portion . 5
8.2 Preparation of the test solution . 6
8.3 Preparation of the calibration solutions . 6
8.4 Optimization of the instrument . 7
8.5 Measurements . 7
8.5.1 Measurement of the calibration solutions . 7
8.5.2 Measurement of the test solutions . 8
8.6 Calibration curves . 8
9 Expression of the results . 8
9.1 Calculation of results . 8
9.2 Precision . 8
9.2.1 Interlaboratory test . 8
9.2.2 Precision data . 8
9.3 Trueness .10
10 Test report .12
Annex A (normative) Checking the performance of an inductively coupled plasma optical
emission spectrometer .13
Annex B (informative) Notes on the interlaboratory test .15
Bibliography .16
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ISO 23156:2021(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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INTERNATIONAL STANDARD ISO 23156:2021(E)
Ferronickels — Determination of phosphorus, manganese,
chromium, copper and cobalt contents — Inductively
coupled plasma optical emission spectrometric method
1 Scope
This document specifies a method for the determination of phosphorus, manganese, chromium, copper
and cobalt contents in ferronickels, by inductively coupled plasma (ICP) optical emission spectrometry,
within the ranges specified in Table 1.
This method is applicable to all grades of ferronickels specified in ISO 6501.
Table 1 — Application ranges of the elements to be determined
Application range
Element
% (mass fraction)
Phosphorus 0,009 to 0,045
Manganese 0,02 to 1,0
Chromium 0,076 to 1,86
Cobalt 0,24 to 1,4
Copper 0,02 to 0,07
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 8049, Ferronickel shot — Sampling for analysis
ISO 8050, Ferronickel ingots or pieces — Sampling for analysis
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO 23156:2021(E)

4 Principle
Dissolution of a test portion with nitric, hydrochloric and hydrofluoric acids. Addition of perchloric
acid to remove fluorine and silicon. Addition of nitric and hydrochloric acids to dissolve the salts. After
suitable dilution and, if necessary, addition of an internal reference element, nebulization of the solution
into an ICP optical emission spectrometer and measurement of the intensity of the emitted light from
each element (including, where relevant, the intensity of the internal reference element).
5 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only
Grade 2 water as specified in ISO 3696.
The same reagents should be used for the preparation of calibration solutions and of sample solutions.
5.1 Pure nickel, containing less than 0,001 % (mass fraction) of P, Mn, Cr, Cu and Co.
5.2 Pure iron, containing less than 0,001 % (mass fraction) of P, Mn, Cr, Cu and Co.
5.3 Hydrochloric acid, HCl, ρ = 1,19 g/ml.
20
5.4 Nitric acid, HNO , ρ = 1,40 g/ml.
3 20
5.5 Nitric acid, HNO , diluted 1 + 1.
3
Add 500 ml of nitric acid (5.4) to 500 ml of water and mix.
5.6 Hydrofluoric acid, HF, ρ = 1,14 g/ml.
20
WARNING — Hydrofluoric acid is extremely irritating and corrosive to skin and mucous
membranes producing severe skin burns which are slow to heal. In case of contact with skin,
wash well with water, apply a topical gel containing 2,5 % (mass fraction) calcium gluconate and
seek immediate medical treatment.
5.7 Perchloric acid, HClO , ρ = 1,54 g/ml.
4 20
WARNING — Perchloric acid vapour may cause explosion in the presence of ammonia, nitrous
fume or organic matter in general. All evaporation shall be carried out in fume hood specifically
designed for the use of perchloric acid.
5.8 Sulfuric acid, H SO , ρ = 1,84 g/ml.
2 4 20
5.9 Internal reference element solution, 1 g/l.
Weigh (1,27 ± 0,001) g of yttrium oxide [minimum purity 99,98 % (mass fraction)] and dissolve in 50 ml
of hydrochloric acid (5.3). Transfer the solution quantitatively into a 1 000 ml one-mark volumetric
flask, dilute to the mark with water and mix.
1 ml of this internal reference element solution contains 1 mg of yttrium.
NOTE Commercially available standard solutions are also used for this purpose.
5.10 Internal reference element solution, 10 mg/l.
Transfer 10,0 ml of the internal reference element solution (5.9) into a 1 000 ml one-mark volumetric
flask, add 50 ml of hydrochloric acid (5.3), dilute to the volume with water and mix.
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ISO 23156:2021(E)

1 ml of this internal reference element solution contains 10 µg of yttrium.
5.11 Phosphorus standard solution, 1 g/l.
Weigh (2,197 ± 0,001) g of potassium dihydrogen phosphate, previously dried to constant mass at 110 °C
and cooled in a desiccator. Dissolve it in a 250 ml beaker with water. Transfer the solution quantitatively
into a 500 ml one-mark volumetric flask, dilute to the volume with water and mix.
1 ml of this solution contains 1 mg of phosphorus.
5.12 Phosphorus standard solution, 0,25 g/l.
Transfer 25,0 ml of the phosphorus standard solution (5.11) into a 100 ml one-mark volumetric flask,
dilute to the volume with water and mix.
1 ml of this standard solution contains 0,25 mg of phosphorus.
5.13 Manganese standard solution, 1 g/l.
The manganese used to prepare the solution is released from superficial oxide possibly present by
introducing a few grams of metal in a 250 ml beaker containing 150 ml to 160 ml of water and 15 ml to
20 ml of sulphuric acid (5.8). Shake and after a few seconds, allow the solution to settle and add water.
Repeat the water cleaning several times. Remove the metallic manganese and rinse with acetone. Dry
the metal in an oven at 100 °C for 2 min or with a hairdryer. Cool in a desiccator.
Weigh (0,5 ± 0,001) g of manganese [minimum purity 99,95 % (mass fraction)] and transfer into a
250 ml beaker. Add 5 ml of hydrochloric acid (5.3) and 10 ml of nitric acid (5.5). Cover with a watch-
glass and heat gently until the metal is dissolved. Boil to remove nitrogen oxides. After cooling, transfer
the solution quantitatively into a 500 ml one-mark volumetric flask, dilute to the volume with water
and mix.
1 ml of this solution contains 1 mg of manganese.
5.14 Chromium standard solution, 1 g/l.
Weigh (0,5 ± 0,001) g of chromium [minimum purity 99,99 % (mass fraction)] and transfer into a 250 ml
beaker. Add 40 ml of hydrochloric acid (5.3), cover with a watch-glass and heat gently until the metal
is completely dissolved. After cooling, transfer the solution quantitatively into a 500 ml one-mark
volumetric flask, dilute to the volume with water and mix.
1 ml of this solution contains 1 mg of chromium.
5.15 Copper standard solution, 1 g/l.
Weigh (0,5 ± 0,001) g of copper [minimum purity 99,95 % (mass fraction)] and transfer into a 250 ml
beaker. Add 30 ml of nitric acid (5.5), cover with a watch-glass and heat gently until the metal is
dissolved. Boil to remove nitrogen oxides. After cooling, transfer the solution quantitatively into a
500 ml one-mark volumetric flask, dilute to the volume with water and mix.
1 ml of this solution contains 1 mg of copper.
5.16 Cobalt standard solution, 1 g/l.
Weigh (0,5 ± 0,001) g of cobalt [minimum purity 99,95 % (mass fraction)] and transfer into a 250 ml
beaker. Add 40 ml of nitric acid (5.5), cover with a watch-glass and heat gently until the metal is
dissolved. Boil to remove nitrogen oxides. After cooling, transfer the solution quantitatively into a
500 ml one-mark volumetric flask, dilute to the volume with water and mix.
1 ml of this solution contains 1 mg of cobalt.
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ISO 23156:2021(E)

5.17 Cobalt standard solution, 0,25 g/l.
Transfer 25,0 ml of the cobalt standard solution (5.16) into a 100 ml one-mark volumetric flask, dilute
to the volume with water and mix.
1 ml of this standard solution contains 0,25 mg of cobalt.
5.18 Multi-elemental standard solution of copper and phosphorus
Transfer 5,0 ml of the copper standard solution (5.15) and 10,0 ml of the phosphorus standard solution
(5.12) into a 100 ml one-mark volumetric flask, dilute to the volume with 5 ml of nitric acid (5.5) and
water then mix.
1 ml of this standard solution respectively contains 50 µg of copper and 25 µg of phosphorus.
5.19 Multi-elemental standard solution of manganese and chromium
Transfer 10,0 ml of the manganese standard solution (5.13) and 25,0 ml of the chromium standard
solution (5.14) into a 100 ml one-mark volumetric flask, dilute to the volume with water and mix.
1 ml of this standard solution respectively contains 0,10 mg of manganese and 0,25 mg of chromium.
6 Apparatus
6.1 General
Ordinary laboratory apparatus and the following.
All volumetric glassware shall be class A and calibrated in accordance with ISO 385, ISO 648 or
ISO 1042, as appropriate.
6.1.1 Polytetrafluoroethylene (PTFE) beakers, of capacity 250 ml.
6.1.2 Polypropylene volumetric flasks, of capacity 100 ml.
6.1.3 Optical emission spectrometer (OES), equipped with ICP.
The spectrometer shall be equipped with a nebulization system. The instrument used will be
satisfactory if, after optimizing in accordance with the manufacturer’s instructions, it meets the
performance requirements given in 6.2.1 to 6.2.5.
The spectrometer can be either a simultaneous or a sequential one. If a sequential spectrometer can be
equipped with an extra arrangement for simultaneous measurement of the internal reference element
line, it can be used with the internal reference element method. If the sequential spectrometer is not
equipped with this arrangement, an internal reference element cannot be used and an alternative
method without an internal reference element should be applied.
6.2 Instrument performance requirements
6.2.1 Wavelengths
This document does not specify particular wavelengths. It is mandatory that
...