SIST ISO 9516-1:2006

Iron ores - Determination of various elements by X-ray fluorescence spectrometry - Part 1: Comprehensive procedure

This part of ISO 9516 sets out a wavelength dispersive X-ray fluorescence procedure for the determination of iron, silicon, calcium, manganese, aluminium, titanium, magnesium, phosphorus, sulfur, potassium, tin, vanadium, chromium, cobalt, nickel, copper, zinc, arsenic, lead and barium in iron ores. The method has been designed to cope with iron ores having high ignition losses.

Minerais de fer - Dosage de divers éléments par spectrométrie de fluorescence de rayons X - Partie 1: Procédure détaillée

Železove rude - Določevanje različnih elementov z rentgensko fluorescentno spektrometrijo - 1. del: Celovit postopek

General Information

• Status: Published
• Publication Date: 30-Sep-2006
• ICS: 73.060.10 - Iron ores
• Technical Committee: IRUD - Mining
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Oct-2006
• Due Date: 01-Oct-2006
• Completion Date: 01-Oct-2006
• Ref Project: ISO 9516-1:2003 - Iron ores — Determination of various elements by X-ray fluorescence spectrometry — Part 1: Comprehensive procedure

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 9516-1
First edition
2003-04-01

Iron ores — Determination of various
elements by X-ray fluorescence
spectrometry —
Part 1:
Comprehensive procedure
Minerais de fer — Dosage de divers éléments par spectrométrie de
fluorescence de rayons X —
Partie 1: Procédure détaillée




Reference number
ISO 9516-1:2003(E)
©
ISO 2003

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ISO 9516-1:2003(E)
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©  ISO 2003
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ii © ISO 2003 — All rights reserved

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ISO 9516-1:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 2
3 Principle . 2
4 Reagents and materials. 2
5 Apparatus. 6
6 Sampling and samples . 7
7 Procedure. 7
8 Calculation of results. 17
9 General treatment of results . 20
10 Test report. 24
Annex A (normative) Preparation of flux A. 25
Annex B (normative) Preparation of flux B or flux C . 27
Annex C (normative) Preparation of synthetic calibration standard . 28
Annex D (normative) Standard deviation of specimen preparation. 30
Annex E (normative) Spectrometer precision tests. 35
Annex F (normative) Determination of the dead time and maximum count rate of the equipment. 39
Annex G (informative) Air cooling block for fused discs . 46
Annex H (informative) Computer program for calculation of results. 47
Annex I (informative) Sample of data for use with calculation program . 60
Annex J (normative) Flowchart for acceptance of results . 65

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ISO 9516-1:2003(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 9516-1 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This first edition, together with ISO 9516-2, cancels and replaces ISO 9516:1992 by the augmentation of the
range of elements under analysis and the diversification into two procedures.
ISO 9516 consists of the following parts, under the general title Iron ores — Determination of various elements
by X-ray fluorescence spectrometry:
 Part 1: Comprehensive procedure
 Part 2: Simplified procedure
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ISO 9516-1:2003(E)
Introduction
In this part of ISO 9516, Table 1 indicates that some determinations may be used for referee purposes and
others for routine analysis only.
A simplified procedure for routine use with all determination will be published in ISO 9516-2.

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INTERNATIONAL STANDARD ISO 9516-1:2003(E)

Iron ores — Determination of various elements by X-ray
fluorescence spectrometry —
Part 1:
Comprehensive procedure
WARNING — This part of ISO 9516 may involve hazardous materials, operations and equipment. This
part of ISO 9516 does not purport to address all of the safety problems associated with its use. It is
the responsibility of the user of this part of ISO 9516 to establish appropriate health and safety
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This part of ISO 9516 sets out a wavelength dispersive X-ray fluorescence procedure for the determination of
iron, silicon, calcium, manganese, aluminium, titanium, magnesium, phosphorus, sulfur, potassium, tin,
vanadium, chromium, cobalt, nickel, copper, zinc, arsenic, lead and barium in iron ores. The method has been
designed to cope with iron ores having high ignition losses.
The method is applicable to iron ores regardless of mineralogical type. The concentration range covered for
each of the component elements is given in Table 1. The determination of total iron cannot be used for referee
purposes.
Table 1 — Range of application of the method
Component Concentration range for Concentration range for
element referee purposes analysis
% %
Fe 38 to 72
Si 0,2 to 6,5 0,2 to 6,5
Ca 0,019 to 12,7 0,019 to 12,7
Mn 0,02 to 0,82 0,02 to 0,82
Al 0,1 to 3,5 0,1 to 3,5
Ti 0,016 to 4,7 0,016 to 4,7
Mg 0,2 to 2,0 0,2 to 2,0
P 0,006 to 0,6 0,006 to 0,6
S 0,04 to 0,6 0,007 to 0,6
K 0,008 to 0,45 0,012 to 0,45
Sn 0,006 to 0,015
V 0,001 7 to 0,3 0,001 7 to 0,3
Cr 0,006 to 0,024
Co 0,006 to 0,018
Ni 0,011 to 0,013
Cu 0,012 to 0,061
Zn 0,006 9 to 0,166 0,005 to 0,166
As 0,008 to 0,06
Pb 0,018 to 0,32 0,018 to 0,32
Ba 0,036 to 0,4
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ISO 9516-1:2003(E)
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 3082:1998, Iron ores — Sampling and sample preparation procedures
ISO 7764:1985, Iron ores — Preparation of predried test samples for chemical analysis
3 Principle
The glass discs for X-ray fluorescence measurement are prepared by incorporating the test portion of the iron
ore sample, via fusion, into a borate glass disc using a casting procedure. By using a fused glass disc, particle
size effects are eliminated. Sodium nitrate is added to the flux to ensure complete oxidation of all components,
particularly iron and sulfur. Any of three methods for glass disc preparation may be used: two use lithium
borate as flux; the other uses sodium borate.
X-ray fluorescence measurements are based on the “line only” principle. It is not necessary to measure
backgrounds on each glass disc, as background equivalent concentrations (BEC) are determined on several
blank glass discs at the line position using concentration-based line-overlap corrections. If desired,
backgrounds can be measured to obtain net line intensities. The method is applicable to data from
simultaneous and sequential X-ray fluorescence spectrometers.
The method relies on measuring all components of the sample, other than volatiles. If some components are
not measured, then errors will result in the measured components (see 7.2.2).
Calibration is carried out using pure chemicals. Results are obtained after matrix corrections for inter-element
effects.
4 Reagents and materials
During analysis, only reagents of recognized high purity shall be used.
NOTE 1 Where reagents have been ignited, they should be covered during cooling in the desiccator and weighed as
soon as possible.
NOTE 2 Reagents 4.2, 4.5, 4.7, 4.8, 4.9, 4.11, 4.13, 4.15, 4.16, 4.18 and 4.20 are used only for the preparation of the
synthetic calibration standard, and are not required if the synthetic calibration standard is available commercially.
4.1 Silicon dioxide, (SiO ), nominally 99,999 % SiO
2 2
The silicon dioxide shall contain less than 3 µg/g of each of the other elements listed in Table 1. It shall be
heated to 1 000 °C in a platinum crucible for a minimum of 2 h and cooled in a desiccator.
4.2 Aluminium oxide, (Al O ), analytical reagent grade, α form
2 3
If the α form is used, it shall be heated to 1 000 °C in a platinum crucible for a minimum of 2 h. If the
aluminium oxide is not the α form, it shall be converted to the α form by heating to 1 250 °C in a platinum
crucible for a minimum of 2 h. It shall be cooled in a desiccator and weighed as soon as it is cool.
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ISO 9516-1:2003(E)
4.3 Iron(III) oxide, (Fe O ), nominally 99,999 % Fe O
2 3 2 3
The iron(III) oxide shall contain less than 3 µg/g of each of the other elements listed in Table 1. It shall be
heated at 1 000 °C in a platinum crucible for a minimum of 1 h and cooled in a desiccator.
4.4 Titanium dioxide, (TiO )
2
Analytical grade titanium dioxide shall be heated at 1 000 °C in a platinum crucible for a minimum of 1 h and
cooled in a desiccator.
Phosphorus is a common impurity in TiO and a reagent low in phosphorus shall be selected. The selected
2
reagent shall be checked, as even nominally high-purity reagents can be significantly contaminated, e.g. a
supposed 99,99 % TiO grade reagent has been found to contain about 0,5 % P O .
2 2 5
4.5 Potassium dihydrogen orthophosphate, (KH PO )
2 4
Analytical grade potassium dihydrogen orthophosphate shall be dried at 105 °C for 1 h and cooled in a
desiccator.
4.6 Calcium carbonate, (CaCO )
3
Analytical grade calcium carbonate shall be dried at 105 °C for 1 h and cooled in a desiccator.
.
4.7 Calcium sulfate, (CaSO 2H O)
4 2
Analytical grade calcium sulfate dihydrate shall be dehydrated at 700 °C for 1 h and cooled in a desiccator.
4.8 Manganese oxide, (Mn O )
3 4
Manganese oxide shall be prepared by heating analytical grade manganese oxide (MnO , MnO or Mn O ) for
2
3 4
15 h at 1 000 °C in a platinum crucible and then cooling. The lumpy material shall be crushed to a fine powder,
heated for 1 h at 200 °C and cooled in a desiccator.
4.9 Magnesium oxide, (MgO)
Analytical grade magnesium oxide shall be dried in a platinum crucible by slowly heating from room
temperature to 1 000 °C. After 1 h at 1 000 °C, the crucible containing the magnesium oxide shall be placed in
a desiccator and weighed as soon as it is cool, as magnesium oxide readily absorbs carbon dioxide from the
atmosphere.
4.10 Sodium nitrate, (NaNO )
3
Analytical grade sodium nitrate shall be dried at 105 °C for 1 h and cooled in a desiccator.
4.11 Tin oxide, (SnO )
2
Analytical grade tin oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.12 Vanadium(V) oxide, (V O )
2 5
Analytical grade vanadium(V) oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.13 Chromium(III) oxide, (Cr O )
2 3
Analytical grade chromium(III) oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
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ISO 9516-1:2003(E)
4.14 Cobalt oxide, (Co O )
3 4
Analytical grade cobalt oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.15 Nickel oxide, (NiO)
Analytical grade nickel oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.16 Copper oxide, (CuO)
Analytical grade copper oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.17 Zinc oxide, (ZnO)
Analytical grade zinc oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
.
4.18 Di-sodium hydrogen arsenate, (Na HAsO 7H O)
2 4 2
The analytical grade reagent shall be weighed as received.
4.19 Lead oxide, (PbO)
Analytical grade lead oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.20 Barium carbonate, (BaCO )
3
Analytical grade barium carbonate shall be heated at 105 °C for a minimum of 1 h and cooled in a desiccator.
4.21 Ammonium iodide, (NH I)
4
Laboratory reagent grade ammonium iodide need not be dried, but shall be stored in a desiccator.
4.22 Desiccant
The desiccant shall be freshly regenerated self-indicating silica gel.
4.23 Flux
4.23.1 General
Flux A, flux B or flux C, as described in 4.23.2, 4.23.3 and 4.23.4, may be used. The levels of contamination in
the flux shall be checked (see 9.1). Because levels of contamination may vary from batch to batch, the same
batch of flux shall be used for all discs (iron ore, blank and calibration) involved in the batch of determinations.
4.23.2 Flux A
Flux A shall be prepared by fusion of a mixture of anhydrous lithium tetraborate (Li B O ) and anhydrous
2 4 7
lithium metaborate (LiBO ) using the procedure specified in Annex A. Flux shall be dried at 500 °C for a
2
minimum of 4 h and stored in a desiccator.
4.23.3 Flux B
Flux B shall be prepared using sodium tetraborate using the procedure specified in Annex B. Flux shall be
dried at 500 °C for a minimum of 4 h and stored in a desiccator.
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ISO 9516-1:2003(E)
4.23.4 Flux C
Flux C shall be prepared using lithium tetraborate using the procedure specified in Annex B. Flux shall be
dried at 500 °C for a minimum of 4 h and stored in a desiccator.
NOTE If this flux is used, sulfur will not be reported.
4.24 Calibration standard
Two independent (i.e. prepared on different days) batches (labelled Day 1 and Day 2) of calibration standard
shall be prepared by the procedure specified in Annex C. The composition of the calibration standard, given in
Table 2, approximates that of an iron ore. The contents of some elements are higher than would be expected
in an iron ore, but this is advantageous for obtaining a reliable calibration.
Prior to weighing, a sufficient aliquot of the calibration standard shall be heated at 900 °C for 20 min and
cooled in a desiccator.
Table 2 — Composition of the calibration standard
Component Content Oxide content
element
% %
Fe 64,000 Fe O
44,764
2 3
Si 4,44 9,500 SiO
2
Ca 3,067 4,2913 CaO
Mn 1,441 2,000 Mn O
3 4
Al 2,65 5,000 Al O
2 3
Ti 1,500 TiO
0,899
2
Mg
3,016 5,000 MgO
P 1,16 2,660 P O
2 5
S 0,921 2,300 SO
3
K 1,46 1,758 9 K O
2
Sn 0,157 5 0,200 SnO
2
V 0,112 0 0,200 V O
2 5
Cr 0,200 Cr O
0,136 8
2 3
Co 0,200 Co O
0,146 8
3 4
Ni
0,157 2 0,200 NiO
Cu 0,159 8 0,200 CuO
Zn
0,160 7 0,200 ZnO
As 0,084 7 0,111 8 As O
2 3
Pb 0,185 7 0,200 PbO
Ba 0,179 1 0,200 BaO
Na 0,052 0 0,070 1 Na O
2
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ISO 9516-1:2003(E)
5 Apparatus
5.1 General
The sample may be fused with the flux in a crucible and then poured into a separate mould or, if an
appropriately shaped crucible is used, the fusion may be carried out and the glass allowed to cool in the same
crucible. Both methods will produce glass discs of the same quality.
A conventional electric furnace, high-frequency furnace, or a gas burner may be used for heating.
There are disc-making machines commercially available, and these may be used to fuse and cast the discs.
A platinum lid may be used to cover the crucible if fusing in a furnace, but not if fusing over a flame, as this
enhances sulfur loss.
Where a high-frequency furnace or a gas burner is used for heating, a check shall be made to determine if
sulfur is lost during disc preparation. A mixture that contains 90 % Fe O and 10 % CaSO shall be prepared
2 3 4
and used to prepare replicate discs using normal fusion times and times of twice and thrice normal. The
intensity of SKα from the discs should not vary by more than 2 % relative.
5.2 Analytical balance, capable of weighing to four decimal places.
5.3 Crucible and mould
5.3.1 General
The crucible and mould shall be made from a non-wetting platinum alloy.
NOTE 1 Either platinum/gold or platinum/gold/rhodium alloys are suitable.
If more than one crucible or more than one mould is used for casting, these crucibles or moulds shall all be
used in the specimen preparation test in Annex D.
NOTE 2 It is essential to use all of the crucibles or moulds, as casting vessels may become distorted with use, giving
the analytical surface a curvature that will result in error.
Sometimes, even undistorted crucibles or moulds give curvatures unique to the particular crucible or mould.
5.3.2 Crucible
Where the crucible is used for fusion only, it shall have sufficient capacity to hold the flux and sample required
for fusion. Where the crucible is used as a mould as well as for fusion, it shall have a flat bottom, to enable
production discs to fit the spectrometer.
5.3.3 Mould
Because the bottom of the disc is the analytical surface, the inside bottom surface of the mould shall be flat
and shall be polished regularly with approximately 3 µm diamond paste to ensure that the glass disc releases
easily from the mould. To prevent deformation through repeated heating and cooling, the base shall be
greater than 2 mm thick.
5.4 Electric furnace, capable of maintaining a temperature of at least 1 050 °C.
The furnace shall be capable of maintaining higher temperatures where it is to be used for converting Al O to
2 3
the α form (1 250 °C), or for preparing flux A (1 100 °C).
The furnace may be of a conventional type with heating elements, or may be a high-frequency furnace. The
furnace shall be cleaned regularly to prevent contamination of the samples.
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ISO 9516-1:2003(E)
5.5 Gas-oxygen burner
Where fusions are made over a gas-oxygen flame, provision shall be made for oxygen enhancement of the
flame to minimize sulfur loss and crucible contamination. The temperature of the melt shall be in the range
1 000 °C to 1 050 °C. The temperature shall be checked using an optical pyrometer while the crucible
contains several grams of flux. Alternatively, if an optical pyrometer is not available, about 3 g of potassium
sulfate (m.p. 1 069 °C) shall be added to the crucible and the flame adjusted so that it all just melts in the open
crucible. A gas burner may be used for heating the mould, and it shall be adjusted so that the mould is a bright
red heat (approximately 950 °C). A Meker burner shall not be used, as loss of sulfur and the uptake of iron
from the glass into the platinum ware may result.
5.6 Desiccator
5.7 Spatulas, non-magnetic, for weighing of the test portion and for mixing.
Vibrating spatulas are not acceptable, because they can lead to segregation of the sample.
5.8 X-ray fluorescence spectrometer, of any wavelength dispersive, vacuum (or helium) path type, X-ray
fluorescence spectrometer, provided that the instrument has been checked. Performance checks shall be
7
carried out in accordance with the precision tests set out in Annex E, accumulating at least 2 × 10 counts for
each measurement.
The dead time for FeKα is determined in the method described in Annex F, and this dead time may be used
for all elements when using a sequential instrument. However, where separate counting channels are used for
the different elements (simultaneous instruments), or where the detector is changed, the dead time of each
channel shall be determined independently. The procedure is given in Annex F.
5.9 Ultrasonic bath, optional. It may be used to aid cleaning of the platinum ware.
5.10 Cooling device
NOTE It is recommended that the mould and glass be cooled using an air jet. Commercial disc-making machines use
this method. A drawing of a suitable device is given in Annex G.
Whatever the method of cooling, it is vital that samples be treated identically, as the curvature of the analytical
surface of the disc depends on the rate of cooling.
6 Sampling and samples
Samples shall be taken and prepared in accordance with ISO 3082. The predried test samples shall be
prepared according to the procedure specified in ISO 7764. The calibration standards shall be heated to
900 °C for 20 min prior to weighing and then cooled in a desiccator.
7 Procedure
7.1 Preparation of discs
7.1.1 General
Independent duplicate sets (Day 1 and Day 2) of test samples, blanks and calibration samples shall be
prepared. The expression “independent” implies that the repetition of the procedure be carried out at a
different time or by a different operator.
The operator shall have demonstrated the ability to consistently make discs with high precision. This ability
shall be verified each month by carrying out the procedure given in Annex D.
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ISO 9516-1:2003(E)
In preparing discs, great care shall be taken to avoid contamination and, in particular, the crucible in which the
fusion is carried out shall be thoroughly cleaned prior to use (see 7.1.8).
7.1.2 Weighing
Table 3 shows the components used in making the glass discs. Provided that the proportions are kept
approximate to those given in Table 3, the masses can be varied to suit mould diameter and shape (see
Note 1).
Table 3 — Masses of specimen components
Mass
a g
Standard masses
Component
Disc diameter
g
32 mm 40 mm
Flux 6,80 4,10 to 4,61 6,40 to 7,20
NaNO 0,40 0,24 to 0,27 0,38 to 0,42
3
Sample 0,66 0,41 to 0,44 0,64 to 0,68
a
Values used to calculate alpha coefficients.
The specified masses may be weighed as “catch” weights, recording the mass weighed to the nearest 0,001 g
for the flux and sodium nitrate portions, and to the nearest 0,000 1 g for the test and calibration portions.
If desired, ammonium iodide (4.21) can be used as a releasing agent. If added at this stage, no more than
0,01 g shall be added. Alternatively, a smaller amount may be added prior to casting (see 7.1.5)
NOTE 1 If a disc diameter used differs from those given in Table 3, masses should be adjusted to be approximately
proportional to the area of the glass disc. If masses used are higher than recommended, crystallization and segregation
with consequent cracking are likely to occur as the glass cools.
NOTE 2 Bromides are used as releasing agents but, since BrLα interferes with AlKα, they are not used in this part of
ISO 9516.
Because the components are hygroscopic, they shall be weighed as soon as possible after reaching room
temperature following heating and without any undue delay between weighings. Weighings may be made
direct into the crucible to be used in the fusion, or into a clean glass vial. Because of static effects, glass vials
are preferable to plastic. If a vial is used, care shall be taken to ensure complete transfer of the contents into
the fusion crucible.
7.1.3 Mixing
Thoroughly mix the components in the crucible using a microspatula or similar implement, taking care that no
material is lost. Brush any fine material adhering to the mixing implement back into the crucible. Gently tap the
bottom of the crucible on the bench top to ensure that any material adhering to the crucible wall, above the
general level of the mixed components, is reincorporated into the bulk of the mix.
It is imperative that the crucible be tapped gently on the bench top, as too severe an impact will result in the
loss of some of the finer material and possible deformation of the crucible.
NOTE The mixing implement used should be free of sharp or pointed edges, in order to ensure that the interior of the
crucible is not damaged by scratching.
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ISO 9516-1:2003(E)
7.1.4 Fusion
For samples containing sulfur as sulfide, the fusion mixture is to be preoxidized by heating to 700 °C for
10 min prior to fusion. Place the crucible in the electric furnace (5.4) or on the gas-oxygen burner (5.5) at a
temperature of 1 000 °C to 1 050 °C and maintain this temperature for 10 min. At least once during this period,
after the sample is dissolved, briefly swirl the mixture. While swirling, incorporate into the melt any material
that may be adhering to the sides of the crucible.
If a furnace is used for heating, it may be necessary to remove the crucible from the furnace for the purpose of
swirling. When the furnace is opened, the temperature may drop. The specified temperature shall be regained
before the time period starts.
7.1.5 Casting
If ammonium iodide was not added as a release agent earlier, it may be added to the melt just prior to casting.
In this case, no more than 0,002 g shall be added. Casting is then carried out by one of the following methods.
a) Casting in the crucible
If the glass is to be cast in the crucible, remove the crucible from the furnace, place on a suitable cooling
device (5.10) and allow the glass to solidify.
b) Casting in a separate mould
If the glass is to be cast in a separate mould, the mould shall be pre-heated over a gas flame to red heat
(900 °C to 1 050 °C). While the mould is still hot, pour the melt into the mould from the crucible. Remove the
mould from the heat source and place it on the cooling device (5.10) and allow the glass to solidify.
NOTE Failure to ensure that the mould is scrupulously clean prior to casting will result in discs sticking to the mould
and possibly cracking.
7.1.6 Visual inspection
Prior to storage, discs shall be inspected visually, paying particular attention to the analytical surface. The
discs shall not contain undissolved material, and shall be whole and free from crystallization, cracks and
bubbles. Defective discs shall be re-fused in the crucible, or discarded and substitute discs prepared.
7.1.7 Disc storage
As soon as possible (while the glass is still warm), transfer the discs to a desiccator so that absorption of
moisture and the possibility of contamination are minimized. When not being measured, discs shall be stored
in a clean desiccator.
To avoid contamination of the analytical su
...

SLOVENSKI STANDARD
SIST ISO 9516-1:2006
01-oktober-2006
äHOH]RYHUXGH'RORþHYDQMHUD]OLþQLKHOHPHQWRY]UHQWJHQVNRIOXRUHVFHQWQR
VSHNWURPHWULMRGHO&HORYLWSRVWRSHN
Iron ores - Determination of various elements by X-ray fluorescence spectrometry - Part
1: Comprehensive procedure
Minerais de fer - Dosage de divers éléments par spectrométrie de fluorescence de
rayons X - Partie 1: Procédure détaillée
Ta slovenski standard je istoveten z: ISO 9516-1:2003
ICS:
73.060.10 Železove rude Iron ores
SIST ISO 9516-1:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 9516-1:2006

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SIST ISO 9516-1:2006


INTERNATIONAL ISO
STANDARD 9516-1
First edition
2003-04-01

Iron ores — Determination of various
elements by X-ray fluorescence
spectrometry —
Part 1:
Comprehensive procedure
Minerais de fer — Dosage de divers éléments par spectrométrie de
fluorescence de rayons X —
Partie 1: Procédure détaillée




Reference number
ISO 9516-1:2003(E)
©
ISO 2003

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SIST ISO 9516-1:2006
ISO 9516-1:2003(E)
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SIST ISO 9516-1:2006
ISO 9516-1:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 2
3 Principle . 2
4 Reagents and materials. 2
5 Apparatus. 6
6 Sampling and samples . 7
7 Procedure. 7
8 Calculation of results. 17
9 General treatment of results . 20
10 Test report. 24
Annex A (normative) Preparation of flux A. 25
Annex B (normative) Preparation of flux B or flux C . 27
Annex C (normative) Preparation of synthetic calibration standard . 28
Annex D (normative) Standard deviation of specimen preparation. 30
Annex E (normative) Spectrometer precision tests. 35
Annex F (normative) Determination of the dead time and maximum count rate of the equipment. 39
Annex G (informative) Air cooling block for fused discs . 46
Annex H (informative) Computer program for calculation of results. 47
Annex I (informative) Sample of data for use with calculation program . 60
Annex J (normative) Flowchart for acceptance of results . 65

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SIST ISO 9516-1:2006
ISO 9516-1:2003(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 9516-1 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This first edition, together with ISO 9516-2, cancels and replaces ISO 9516:1992 by the augmentation of the
range of elements under analysis and the diversification into two procedures.
ISO 9516 consists of the following parts, under the general title Iron ores — Determination of various elements
by X-ray fluorescence spectrometry:
 Part 1: Comprehensive procedure
 Part 2: Simplified procedure
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Introduction
In this part of ISO 9516, Table 1 indicates that some determinations may be used for referee purposes and
others for routine analysis only.
A simplified procedure for routine use with all determination will be published in ISO 9516-2.

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SIST ISO 9516-1:2006
INTERNATIONAL STANDARD ISO 9516-1:2003(E)

Iron ores — Determination of various elements by X-ray
fluorescence spectrometry —
Part 1:
Comprehensive procedure
WARNING — This part of ISO 9516 may involve hazardous materials, operations and equipment. This
part of ISO 9516 does not purport to address all of the safety problems associated with its use. It is
the responsibility of the user of this part of ISO 9516 to establish appropriate health and safety
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This part of ISO 9516 sets out a wavelength dispersive X-ray fluorescence procedure for the determination of
iron, silicon, calcium, manganese, aluminium, titanium, magnesium, phosphorus, sulfur, potassium, tin,
vanadium, chromium, cobalt, nickel, copper, zinc, arsenic, lead and barium in iron ores. The method has been
designed to cope with iron ores having high ignition losses.
The method is applicable to iron ores regardless of mineralogical type. The concentration range covered for
each of the component elements is given in Table 1. The determination of total iron cannot be used for referee
purposes.
Table 1 — Range of application of the method
Component Concentration range for Concentration range for
element referee purposes analysis
% %
Fe 38 to 72
Si 0,2 to 6,5 0,2 to 6,5
Ca 0,019 to 12,7 0,019 to 12,7
Mn 0,02 to 0,82 0,02 to 0,82
Al 0,1 to 3,5 0,1 to 3,5
Ti 0,016 to 4,7 0,016 to 4,7
Mg 0,2 to 2,0 0,2 to 2,0
P 0,006 to 0,6 0,006 to 0,6
S 0,04 to 0,6 0,007 to 0,6
K 0,008 to 0,45 0,012 to 0,45
Sn 0,006 to 0,015
V 0,001 7 to 0,3 0,001 7 to 0,3
Cr 0,006 to 0,024
Co 0,006 to 0,018
Ni 0,011 to 0,013
Cu 0,012 to 0,061
Zn 0,006 9 to 0,166 0,005 to 0,166
As 0,008 to 0,06
Pb 0,018 to 0,32 0,018 to 0,32
Ba 0,036 to 0,4
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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 3082:1998, Iron ores — Sampling and sample preparation procedures
ISO 7764:1985, Iron ores — Preparation of predried test samples for chemical analysis
3 Principle
The glass discs for X-ray fluorescence measurement are prepared by incorporating the test portion of the iron
ore sample, via fusion, into a borate glass disc using a casting procedure. By using a fused glass disc, particle
size effects are eliminated. Sodium nitrate is added to the flux to ensure complete oxidation of all components,
particularly iron and sulfur. Any of three methods for glass disc preparation may be used: two use lithium
borate as flux; the other uses sodium borate.
X-ray fluorescence measurements are based on the “line only” principle. It is not necessary to measure
backgrounds on each glass disc, as background equivalent concentrations (BEC) are determined on several
blank glass discs at the line position using concentration-based line-overlap corrections. If desired,
backgrounds can be measured to obtain net line intensities. The method is applicable to data from
simultaneous and sequential X-ray fluorescence spectrometers.
The method relies on measuring all components of the sample, other than volatiles. If some components are
not measured, then errors will result in the measured components (see 7.2.2).
Calibration is carried out using pure chemicals. Results are obtained after matrix corrections for inter-element
effects.
4 Reagents and materials
During analysis, only reagents of recognized high purity shall be used.
NOTE 1 Where reagents have been ignited, they should be covered during cooling in the desiccator and weighed as
soon as possible.
NOTE 2 Reagents 4.2, 4.5, 4.7, 4.8, 4.9, 4.11, 4.13, 4.15, 4.16, 4.18 and 4.20 are used only for the preparation of the
synthetic calibration standard, and are not required if the synthetic calibration standard is available commercially.
4.1 Silicon dioxide, (SiO ), nominally 99,999 % SiO
2 2
The silicon dioxide shall contain less than 3 µg/g of each of the other elements listed in Table 1. It shall be
heated to 1 000 °C in a platinum crucible for a minimum of 2 h and cooled in a desiccator.
4.2 Aluminium oxide, (Al O ), analytical reagent grade, α form
2 3
If the α form is used, it shall be heated to 1 000 °C in a platinum crucible for a minimum of 2 h. If the
aluminium oxide is not the α form, it shall be converted to the α form by heating to 1 250 °C in a platinum
crucible for a minimum of 2 h. It shall be cooled in a desiccator and weighed as soon as it is cool.
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4.3 Iron(III) oxide, (Fe O ), nominally 99,999 % Fe O
2 3 2 3
The iron(III) oxide shall contain less than 3 µg/g of each of the other elements listed in Table 1. It shall be
heated at 1 000 °C in a platinum crucible for a minimum of 1 h and cooled in a desiccator.
4.4 Titanium dioxide, (TiO )
2
Analytical grade titanium dioxide shall be heated at 1 000 °C in a platinum crucible for a minimum of 1 h and
cooled in a desiccator.
Phosphorus is a common impurity in TiO and a reagent low in phosphorus shall be selected. The selected
2
reagent shall be checked, as even nominally high-purity reagents can be significantly contaminated, e.g. a
supposed 99,99 % TiO grade reagent has been found to contain about 0,5 % P O .
2 2 5
4.5 Potassium dihydrogen orthophosphate, (KH PO )
2 4
Analytical grade potassium dihydrogen orthophosphate shall be dried at 105 °C for 1 h and cooled in a
desiccator.
4.6 Calcium carbonate, (CaCO )
3
Analytical grade calcium carbonate shall be dried at 105 °C for 1 h and cooled in a desiccator.
.
4.7 Calcium sulfate, (CaSO 2H O)
4 2
Analytical grade calcium sulfate dihydrate shall be dehydrated at 700 °C for 1 h and cooled in a desiccator.
4.8 Manganese oxide, (Mn O )
3 4
Manganese oxide shall be prepared by heating analytical grade manganese oxide (MnO , MnO or Mn O ) for
2
3 4
15 h at 1 000 °C in a platinum crucible and then cooling. The lumpy material shall be crushed to a fine powder,
heated for 1 h at 200 °C and cooled in a desiccator.
4.9 Magnesium oxide, (MgO)
Analytical grade magnesium oxide shall be dried in a platinum crucible by slowly heating from room
temperature to 1 000 °C. After 1 h at 1 000 °C, the crucible containing the magnesium oxide shall be placed in
a desiccator and weighed as soon as it is cool, as magnesium oxide readily absorbs carbon dioxide from the
atmosphere.
4.10 Sodium nitrate, (NaNO )
3
Analytical grade sodium nitrate shall be dried at 105 °C for 1 h and cooled in a desiccator.
4.11 Tin oxide, (SnO )
2
Analytical grade tin oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.12 Vanadium(V) oxide, (V O )
2 5
Analytical grade vanadium(V) oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.13 Chromium(III) oxide, (Cr O )
2 3
Analytical grade chromium(III) oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
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4.14 Cobalt oxide, (Co O )
3 4
Analytical grade cobalt oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.15 Nickel oxide, (NiO)
Analytical grade nickel oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.16 Copper oxide, (CuO)
Analytical grade copper oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.17 Zinc oxide, (ZnO)
Analytical grade zinc oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
.
4.18 Di-sodium hydrogen arsenate, (Na HAsO 7H O)
2 4 2
The analytical grade reagent shall be weighed as received.
4.19 Lead oxide, (PbO)
Analytical grade lead oxide shall be heated at 400 °C for a minimum of 1 h and cooled in a desiccator.
4.20 Barium carbonate, (BaCO )
3
Analytical grade barium carbonate shall be heated at 105 °C for a minimum of 1 h and cooled in a desiccator.
4.21 Ammonium iodide, (NH I)
4
Laboratory reagent grade ammonium iodide need not be dried, but shall be stored in a desiccator.
4.22 Desiccant
The desiccant shall be freshly regenerated self-indicating silica gel.
4.23 Flux
4.23.1 General
Flux A, flux B or flux C, as described in 4.23.2, 4.23.3 and 4.23.4, may be used. The levels of contamination in
the flux shall be checked (see 9.1). Because levels of contamination may vary from batch to batch, the same
batch of flux shall be used for all discs (iron ore, blank and calibration) involved in the batch of determinations.
4.23.2 Flux A
Flux A shall be prepared by fusion of a mixture of anhydrous lithium tetraborate (Li B O ) and anhydrous
2 4 7
lithium metaborate (LiBO ) using the procedure specified in Annex A. Flux shall be dried at 500 °C for a
2
minimum of 4 h and stored in a desiccator.
4.23.3 Flux B
Flux B shall be prepared using sodium tetraborate using the procedure specified in Annex B. Flux shall be
dried at 500 °C for a minimum of 4 h and stored in a desiccator.
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4.23.4 Flux C
Flux C shall be prepared using lithium tetraborate using the procedure specified in Annex B. Flux shall be
dried at 500 °C for a minimum of 4 h and stored in a desiccator.
NOTE If this flux is used, sulfur will not be reported.
4.24 Calibration standard
Two independent (i.e. prepared on different days) batches (labelled Day 1 and Day 2) of calibration standard
shall be prepared by the procedure specified in Annex C. The composition of the calibration standard, given in
Table 2, approximates that of an iron ore. The contents of some elements are higher than would be expected
in an iron ore, but this is advantageous for obtaining a reliable calibration.
Prior to weighing, a sufficient aliquot of the calibration standard shall be heated at 900 °C for 20 min and
cooled in a desiccator.
Table 2 — Composition of the calibration standard
Component Content Oxide content
element
% %
Fe 64,000 Fe O
44,764
2 3
Si 4,44 9,500 SiO
2
Ca 3,067 4,2913 CaO
Mn 1,441 2,000 Mn O
3 4
Al 2,65 5,000 Al O
2 3
Ti 1,500 TiO
0,899
2
Mg
3,016 5,000 MgO
P 1,16 2,660 P O
2 5
S 0,921 2,300 SO
3
K 1,46 1,758 9 K O
2
Sn 0,157 5 0,200 SnO
2
V 0,112 0 0,200 V O
2 5
Cr 0,200 Cr O
0,136 8
2 3
Co 0,200 Co O
0,146 8
3 4
Ni
0,157 2 0,200 NiO
Cu 0,159 8 0,200 CuO
Zn
0,160 7 0,200 ZnO
As 0,084 7 0,111 8 As O
2 3
Pb 0,185 7 0,200 PbO
Ba 0,179 1 0,200 BaO
Na 0,052 0 0,070 1 Na O
2
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SIST ISO 9516-1:2006
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5 Apparatus
5.1 General
The sample may be fused with the flux in a crucible and then poured into a separate mould or, if an
appropriately shaped crucible is used, the fusion may be carried out and the glass allowed to cool in the same
crucible. Both methods will produce glass discs of the same quality.
A conventional electric furnace, high-frequency furnace, or a gas burner may be used for heating.
There are disc-making machines commercially available, and these may be used to fuse and cast the discs.
A platinum lid may be used to cover the crucible if fusing in a furnace, but not if fusing over a flame, as this
enhances sulfur loss.
Where a high-frequency furnace or a gas burner is used for heating, a check shall be made to determine if
sulfur is lost during disc preparation. A mixture that contains 90 % Fe O and 10 % CaSO shall be prepared
2 3 4
and used to prepare replicate discs using normal fusion times and times of twice and thrice normal. The
intensity of SKα from the discs should not vary by more than 2 % relative.
5.2 Analytical balance, capable of weighing to four decimal places.
5.3 Crucible and mould
5.3.1 General
The crucible and mould shall be made from a non-wetting platinum alloy.
NOTE 1 Either platinum/gold or platinum/gold/rhodium alloys are suitable.
If more than one crucible or more than one mould is used for casting, these crucibles or moulds shall all be
used in the specimen preparation test in Annex D.
NOTE 2 It is essential to use all of the crucibles or moulds, as casting vessels may become distorted with use, giving
the analytical surface a curvature that will result in error.
Sometimes, even undistorted crucibles or moulds give curvatures unique to the particular crucible or mould.
5.3.2 Crucible
Where the crucible is used for fusion only, it shall have sufficient capacity to hold the flux and sample required
for fusion. Where the crucible is used as a mould as well as for fusion, it shall have a flat bottom, to enable
production discs to fit the spectrometer.
5.3.3 Mould
Because the bottom of the disc is the analytical surface, the inside bottom surface of the mould shall be flat
and shall be polished regularly with approximately 3 µm diamond paste to ensure that the glass disc releases
easily from the mould. To prevent deformation through repeated heating and cooling, the base shall be
greater than 2 mm thick.
5.4 Electric furnace, capable of maintaining a temperature of at least 1 050 °C.
The furnace shall be capable of maintaining higher temperatures where it is to be used for converting Al O to
2 3
the α form (1 250 °C), or for preparing flux A (1 100 °C).
The furnace may be of a conventional type with heating elements, or may be a high-frequency furnace. The
furnace shall be cleaned regularly to prevent contamination of the samples.
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5.5 Gas-oxygen burner
Where fusions are made over a gas-oxygen flame, provision shall be made for oxygen enhancement of the
flame to minimize sulfur loss and crucible contamination. The temperature of the melt shall be in the range
1 000 °C to 1 050 °C. The temperature shall be checked using an optical pyrometer while the crucible
contains several grams of flux. Alternatively, if an optical pyrometer is not available, about 3 g of potassium
sulfate (m.p. 1 069 °C) shall be added to the crucible and the flame adjusted so that it all just melts in the open
crucible. A gas burner may be used for heating the mould, and it shall be adjusted so that the mould is a bright
red heat (approximately 950 °C). A Meker burner shall not be used, as loss of sulfur and the uptake of iron
from the glass into the platinum ware may result.
5.6 Desiccator
5.7 Spatulas, non-magnetic, for weighing of the test portion and for mixing.
Vibrating spatulas are not acceptable, because they can lead to segregation of the sample.
5.8 X-ray fluorescence spectrometer, of any wavelength dispersive, vacuum (or helium) path type, X-ray
fluorescence spectrometer, provided that the instrument has been checked. Performance checks shall be
7
carried out in accordance with the precision tests set out in Annex E, accumulating at least 2 × 10 counts for
each measurement.
The dead time for FeKα is determined in the method described in Annex F, and this dead time may be used
for all elements when using a sequential instrument. However, where separate counting channels are used for
the different elements (simultaneous instruments), or where the detector is changed, the dead time of each
channel shall be determined independently. The procedure is given in Annex F.
5.9 Ultrasonic bath, optional. It may be used to aid cleaning of the platinum ware.
5.10 Cooling device
NOTE It is recommended that the mould and glass be cooled using an air jet. Commercial disc-making machines use
this method. A drawing of a suitable device is given in Annex G.
Whatever the method of cooling, it is vital that samples be treated identically, as the curvature of the analytical
surface of the disc depends on the rate of cooling.
6 Sampling and samples
Samples shall be taken and prepared in accordance with ISO 3082. The predried test samples shall be
prepared according to the procedure specified in ISO 7764. The calibration standards shall be heated to
900 °C for 20 min prior to weighing and then cooled in a desiccator.
7 Procedure
7.1 Preparation of discs
7.1.1 General
Independent duplicate sets (Day 1 and Day 2) of test samples, blanks and calibration samples shall be
prepared. The expression “independent” implies that the repetition of the procedure be carried out at a
different time or by a different operator.
The operator shall have demonstrated the ability to consistently make discs with high precision. This ability
shall be verified each month by carrying out the procedure given in Annex D.
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In preparing discs, great care shall be taken to avoid contamination and, in particular, the crucible in which the
fusion is carried out shall be thoroughly cleaned prior to use (see 7.1.8).
7.1.2 Weighing
Table 3 shows the components used in making the glass discs. Provided that the proportions are kept
approximate to those given in Table 3, the masses can be varied to suit mould diameter and shape (see
Note 1).
Table 3 — Masses of specimen components
Mass
a g
Standard masses
Component
Disc diameter
g
32 mm 40 mm
Flux 6,80 4,10 to 4,61 6,40 to 7,20
NaNO 0,40 0,24 to 0,27 0,38 to 0,42
3
Sample 0,66 0,41 to 0,44 0,64 to 0,68
a
Values used to calculate alpha coefficients.
The specified masses may be weighed as “catch” weights, recording the mass weighed to the nearest 0,001 g
for the flux and sodium nitrate portions, and to the nearest 0,000 1 g for the test and calibration portions.
If desired, ammonium iodide (4.21) can be used as a releasing agent. If added at this stage, no more than
0,01 g shall be added. Alternatively, a smaller amount may be added prior to casting (see 7.1.5)
NOTE 1 If a disc diameter used differs from those given in Table 3, masses should be adjusted to be approximately
proportional to the area of the glass disc. If masses used are higher than recommended, crystallization and segregation
with consequent cracking are likely to occur as the glass cools.
NOTE 2 Bromides are used as releasing agents but, since BrLα interferes with AlKα, they are not used in this part of
ISO 9516.
Because the components are hygroscopic, they shall be weighed as soon as possible after reaching room
temperature following heating and without any undue delay between weighings. Weighings may be made
direct into the crucible to be used in the fusion, or into a clean glass vial. Because of static effects, glass vials
are preferable to plastic. If a vial is used, care shall be taken to ensure complete transfer of the contents into
the fusion crucible.
7.1.3 Mixing
Thoroughly mix the components in the crucible using a microspatula or similar implement, taking care that no
material is lost. Brush any fine material adhering to the mixing implement back into the crucible. Gently tap the
bottom of the crucible on the bench top to ensure that any material adhering to the crucible wall, above the
general level of the mixed components, is reincorporated into the bulk of the mix.
It is imperative that the crucible be tapped gently on the bench top, as too severe an impact will result in the
loss of some of the finer material and possible deformation of the crucible.
NOTE The mixing implement used should be free of sharp or pointed edges, in order to ensure that the interior of the
crucible is not damaged by scratching.
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7.1.4 Fusion
For samples containing sulfur as sulfide, the fusion mixture is to be preoxidized by heating to 700 °C for
10 min prior to fusion. Place the crucible in the electric furnace (5.4) or on the gas-oxygen burner (5.5) at a
temperature of 1 000 °C to 1 050 °C and maintain this temperature for 10 min. At least once during this period,
after the sample is dissolved, briefly swirl the mixture. While swirling, incorporate into the melt any material
that may be adhering to the sides of the crucible.
If a furnace is used for heating, it may be necessary to remove the crucible from the furnace for the purpose of
swirling. When the furnace is opened, the temperature may drop. The specified temperature shall be regained
before the time period starts.
7.1.5 Casting
If ammonium iodide was not added as a release agent earlier, it may be added to the melt just prior to casting.
In this case, no more than 0,002 g shall be added. Casting is then carried out by one of the following methods.
a) Casting in the crucible
If the glass is to be cast in the crucible, remove the crucible from the furnace, place on a suitable cooling
device (5.10) and a
...