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

ISO 9516-1:2003 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.

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
02-Apr-2003
Current Stage
9093 - International Standard confirmed
Start Date
10-Apr-2014
Completion Date
24-Jun-2022

Buy Standard

Standard
ISO 9516-1:2003 - Iron ores -- Determination of various elements by X-ray fluorescence spectrometry
English language
65 pages
sale 15% off
Preview
sale 15% off
Preview
Standard
ISO 9516-1:2006
English language
70 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day

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
---------------------- Page: 1 ----------------------
ISO 9516-1:2003(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2003

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2003 — All rights reserved
---------------------- Page: 2 ----------------------
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

© ISO 2003 — All rights reserved iii
---------------------- Page: 3 ----------------------
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
iv © ISO 2003 — All rights reserved
---------------------- Page: 4 ----------------------
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.

© ISO 2003 — All rights reserved v
---------------------- Page: 5 ----------------------
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
© ISO 2003 — All rights reserved 1
---------------------- Page: 6 ----------------------
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.

2 © ISO 2003 — All rights reserved
---------------------- Page: 7 ----------------------
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 )

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

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 )

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

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 )

Analytical grade sodium nitrate shall be dried at 105 °C for 1 h and cooled in a desiccator.

4.11 Tin oxide, (SnO )

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.

© ISO 2003 — All rights reserved 3
---------------------- Page: 8 ----------------------
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 )

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)

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

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.
4 © ISO 2003 — All rights reserved
---------------------- Page: 9 ----------------------
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
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
3,016 5,000 MgO
P 1,16 2,660 P O
2 5
S 0,921 2,300 SO
K 1,46 1,758 9 K O
Sn 0,157 5 0,200 SnO
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
0,157 2 0,200 NiO
Cu 0,159 8 0,200 CuO
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
© ISO 2003 — All rights reserved 5
---------------------- Page: 10 ----------------------
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.
6 © ISO 2003 — All rights reserved
---------------------- Page: 11 ----------------------
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

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.
© ISO 2003 — All rights reserved 7
---------------------- Page: 12 ----------------------
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
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
Sample 0,66 0,41 to 0,44 0,64 to 0,68
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.
8 © ISO 2003 — All rights reserved
---------------------- Page: 13 ----------------------
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.

---------------------- Page: 1 ----------------------
SIST ISO 9516-1:2006
---------------------- Page: 2 ----------------------
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
---------------------- Page: 3 ----------------------
SIST ISO 9516-1:2006
ISO 9516-1:2003(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2003

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2003 — All rights reserved
---------------------- Page: 4 ----------------------
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

© ISO 2003 — All rights reserved iii
---------------------- Page: 5 ----------------------
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
iv © ISO 2003 — All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 9516-1:2006
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.

© ISO 2003 — All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 9516-1:2006
---------------------- Page: 8 ----------------------
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
© ISO 2003 — All rights reserved 1
---------------------- Page: 9 ----------------------
SIST ISO 9516-1:2006
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.

2 © ISO 2003 — All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 9516-1:2006
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 )

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

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 )

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

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 )

Analytical grade sodium nitrate shall be dried at 105 °C for 1 h and cooled in a desiccator.

4.11 Tin oxide, (SnO )

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.

© ISO 2003 — All rights reserved 3
---------------------- Page: 11 ----------------------
SIST ISO 9516-1:2006
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 )

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)

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

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.
4 © ISO 2003 — All rights reserved
---------------------- Page: 12 ----------------------
SIST ISO 9516-1:2006
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
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
3,016 5,000 MgO
P 1,16 2,660 P O
2 5
S 0,921 2,300 SO
K 1,46 1,758 9 K O
Sn 0,157 5 0,200 SnO
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
0,157 2 0,200 NiO
Cu 0,159 8 0,200 CuO
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
© ISO 2003 — All rights reserved 5
---------------------- Page: 13 ----------------------
SIST ISO 9516-1:2006
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.
6 © ISO 2003 — All rights reserved
---------------------- Page: 14 ----------------------
SIST ISO 9516-1:2006
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

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.
© ISO 2003 — All rights reserved 7
---------------------- Page: 15 ----------------------
SIST ISO 9516-1:2006
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
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
Sample 0,66 0,41 to 0,44 0,64 to 0,68
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.
8 © ISO 2003 — All rights reserved
---------------------- Page: 16 ----------------------
SIST ISO 9516-1:2006
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 a
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.