ISO 3087:1998

SLOVENSKI STANDARD
SIST ISO 3087:2000
01-junij-2000
äHOH]RYHUXGH'RORþHYDQMHYODJHYY]RUFX
Iron ores -- Determination of moisture content of a lot
Minerais de fer -- Détermination de l'humidité d'un lot
Ta slovenski standard je istoveten z: ISO 3087:1998
ICS:
73.060.10 Železove rude Iron ores
SIST ISO 3087:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 3087:2000

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SIST ISO 3087:2000
INTERNATIONAL ISO
STANDARD 3087
Third edition
1998-12-15
Iron ores — Determination of the moisture
content of a lot
Minerais de fer — Détermination de l’humidité d’un lot
A
Reference number
ISO 3087:1998(E)

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SIST ISO 3087:2000
ISO 3087:1998(E)
Contents Page
1 Scope .1
2 Normative references .1
3 Definitions .1
4 Principle.1
5 Apparatus .1
6 Samples .2
7 Procedure .2
8 Verification .3
9 Calculation and expression of results.3
10 Test report .5
Annex A (normative) Determination of moisture content of adhesive or wet iron ores .6
Annex B (normative) Corrections for sprinkled water and/or rain-water .7
Annex C (informative) Precision of moisture measurement.12
Annex D (informative) Examples of test reports .13
©  ISO 1998
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 the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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SIST ISO 3087:2000
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ISO 3087:1998(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.
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.
International Standard ISO 3087 was prepared by Technical Committee ISO/TC 102, Iron ores, Subcommittee 1,
Sampling
This third edition cancels and replaces the second edition (ISO 3087:1987) which has been technically revised.
Annexes A and B form an integral part of this of this International Standard, annexes C and D are for information
only.
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SIST ISO 3087:2000
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ISO 3087:1998(E)
Introduction
Currenly, large tonnages of iron ore are traded internationally and a small error in the measured moisture content
(percentage by mass) of a lot has a considerable effect on the commercial transaction. The correct determination of
moisture content of a lot is, therefore, a matter of importance for both the purchaser and the vendor.
This International Standard does not address the determination of the hygroscopic moisture content of a test
sample for chemical analysis. If the hygroscopic moisture content is required to be determined, reference should be
made to ISO 2596:1994, Iron ores – Determination of hygroscopic moisture in analytical samples – Gravimetric and
Karl Fischer methods.
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SIST ISO 3087:2000
©
INTERNATIONAL STANDARD  ISO ISO 3087:1998(E)
Iron ores — Determination of the moisture content of a lot
1 Scope
This International Standard specifies a method for the determination of the moisture content of a lot of iron ore. This
method is applicable to all iron ores, whether natural or processed.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
1)
ISO 3082:— , Iron ores – Sampling and sample preparation procedures.
ISO 11323:1996, Iron ores – Vocabulary.
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 11323 apply.
4 Principle
Drying of the test portion in air at 105 °C to constant mass and measurement of the loss in mass. Calculation of the
moisture content.
5 Apparatus
5.1  Drying pan, having a smooth surface, free from contamination and capable of accommodating the specified
quantity of a test portion in a layer of nominal thickness not greater than 31,5 mm.
5.2  Drying oven, equipped with a temperature indicator and control apparatus capable of regulating the
temperature at any point in the oven at 105 °C – 5° C and so designed as to maintain this temperature with a
current of air to ensure efficient drying but without any loss of sample, and fitted with a fan that allows for both the
circulation and change of air.
5.3  Weighing device, accurate to at least 0,05 % of the initial mass of a test portion.
The capacity of the weighing device shall be enough for the initial mass of the test portion.

1)
To be published. (Revision of ISO 3081:1986, ISO 3082:1987 and ISO 3083:1986)
1

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ISO 3087:1998(E)
6 Samples
Test samples which have been taken and prepared in accordance with ISO 3082 shall be used. The mass of a test
portion, in relation to its nominal top size, is specified in table 1, in accordance with ISO 3082.
Table 1 — Minimum mass of test portion
Nominal top size Minimum mass
of test portion of test portion
(mm) (kg)
31,5 10
22,4 5
10,0 1
7 Procedure
7.1 Number of moisture measurements
Carry out one moisture measurement per test portion on the number of test portions specified in table 2, according
to the conditions of preparation of the test sample.
Table 2 — Number of test portions
Preparation Number of Number of
of test sample partial samples per lot test portions to be tested
From gross sample – 4
24
From partial sample 3 to 7 2 minimum
> 8 1 minimum
From increment - 1 minimum
In order to minimize losses of moisture to the atmosphere, it is necessary to perform all the initial weighings of the
test portions as quickly as possible after obtaining those test portions.
7.2 Measurement
Spread the test portion in a layer of nominal thickness not greater than 31,5 mm in the tared drying pan (5.1) and
determine the total mass immediately. Record the total mass, the mass of the drying pan, the initial mass of the test
portion (m ) and the numerical value of 0,05 % of the initial mass of the test portion.
1
Place the drying pan with the test portion in the drying oven (5.2) set at 105 °C, and maintain this temperature for
not less than 4 h. Remove the drying pan with the test portion from the drying oven and weigh it immediately while
still hot in order to minimize any reabsorption of moisture. Alternatively, weigh the test portion after cooling in air in a
container having a close-fitting airtight lid. In each case, report the method of weighing.
Place once more, the drying pan with the test portion in the drying oven, heat for a further 1 h, and then repeat the
weighing.
Repeat the procedure in the previous paragraph until the difference in mass between subsequent measurements
becomes 0,05 % or less of the initial mass of the test portion.
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NOTE 1  The weighing device should be protected from the influence of heat.
NOTE 2  Drying times will be dependent on the type of ore under test. For a series of measurements carried out on a particular
type of ore, the drying time of the test portion may be specified by check experiments carried out beforehand.
NOTE 3  For convenience, the test portion of mass 10 kg for ore of particle size less than 31,5 mm may be divided into two
portions, each of which is subjected to moisture measurement. In calculating the results, the mean of the two values of initial
mass and the mean of the two values of the drying loss in mass should be used.
8 Verification
Regular checking of apparatus and procedures is essential to verify the test results. Checks shall be carried out
prior to the commencement of a routine test in accordance with this International Standard and at regular intervals
thereafter. The frequency of checking is a matter for each laboratory to determine. A detailed record of all
verification activities shall be maintained for the following items:
a) Sprinkled water measurement
 volumenometer;
b) Rainfall measurement
 rain gauge;
c) Moisture test
 oven temperature/temperature regulation;
 circulation and change of air in oven;
 weighing device.
9 Calculation and expression of results
9.1 Test portion
The result of the determination of the moisture content, w, expressed as a percentage by mass, for each test
i
portion, is given by equation (1) and reported to the second decimal place.
−
mm
12
w= × 100 (1)
i
m
1
where
m is the initial mass, in grams, of the test portion;
1
m is the mass, in grams, of the test portion after drying.
2
9.2 Lot
The moisture content of a lot is given by one of equations (2) to (5) as the occasion may demand, and reported to
the first decimal place.
9.2.1  When moisture determination is conducted on the gross sample from the lot, the moisture of the lot is
determined as follows.
3

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When the range of the four test results does not exceed 1,3r as shown in table 3, the arithmetic mean, w , of the
four results shall be the moisture content, expressed as a percentage by mass, of the lot as given by equation (2).
ww+++w w
12 3 4
w= (2)
4
where w , w , w and w are the results of the determinations of the moisture contents, expressed as percentages
1 2 3 4
by mass, on each of the four test portions.
When the range of the four test results exceeds 1,3r given in table 3, the median shall be taken as the moisture
content of the lot. The median of four test results is defined as the mean of the two non-extreme test results.
Table 3 — Repeatability limit of moisture determination on the gross sample
Average of moisture content Repeatability limit 1,3r
w
r
(%) (%)
[%(m/m)]

w < 3 0,20 0,26
3 , w < 6 0,25 0,33
6 , w 0,31 0,40
9.2.2  When mass basis sampling has been performed and moisture determination is conducted on each partial
sample, the weighted mean, w , of the results from all the partial samples, considering the number of increments for
each partial sample, shall be the moisture content, expressed as a percentage by mass, of the lot, as given by
equation (3),
k
Nw
ii
∑
i=1
w= (3)
k
N
i
∑
i=1
where
k is the number of partial samples;
i
N is the number of increments in the th partial sample;
i
w is the result of the determination of the moisture content, expressed as a percentage by mass, of the ith
i
partial sample, according to table 2 using as the number of test portions either 4 or 2.
If it is impracticable to sample the lot as a whole or desirable to sample a lot in separate parts of unequal mass as in
the case of time basis sampling, the moisture content of each part shall be determined independently and the
weighted mean, w , of the results, expressed as a percentage by mass, of the lot calculated from the individual
results using equation (4).
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SIST ISO 3087:2000
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k
mw
ii
∑
i=1
w= (4)
k
m
i
∑
i=1
where
k is the number of partial samples;
m is the mass of the ith part;
i
w is the result of the determination of the moisture content, expressed as a percentage by mass, of the ith
i
part.
 When moisture determination is conducted on each increment, the arithmetic mean, , of the results for all
9.2.3 w
increments obtained according to 9.1 shall be the moisture content, expressed as a percentage by mass, of the lot
as given by equation (5)
n
w
i
∑
i = 1
w = (5)
n
where
n is the number of increments;
w is the result of the determination of the moisture content, expressed as a percentage by mass, of the ith
i
increment.
10 Test report
The test report shall contain the following information.
a) reference to this International Standard, i.e., ISO 3087;
b) details necessary for the identification of the sample;
c) result of the test;
d) reference number of the result;
e) any characteristics noticed during the determination, and any operation not specified in this International
Standard which may have had an influence on the results.
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SIST ISO 3087:2000
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ISO 3087:1998(E)
Annex A
(normative)
Determination of moisture content of adhesive or wet iron ores
Introduction
When it is difficult to conduct sieving, crushing and dividing owing to a sample being adhesive or excessively wet,
the sample may be pre-dried until preparation can be conducted without difficulty.
In this case, the moisture content of the lot shall be obtained by using the pre-drying method according to the
procedure specified in this annex. In handling the test sample and weighing the initial mass and pre-dried mass of
the test sample, attention shall be paid to ensuring the measurement precision of the pre-dried moisture content.
A.1  Determine the initial mass of the test sample.
A.2  Spread the test sample in a uniform thickness and dry it in air or in a drying apparatus at a temperature no
higher than 105 °C. The choice of temperature and time for this pre-drying stage shall not exceed a point where an
ore is likely to reabsorb moisture during subsequent processing.
A.3  After pre-drying, again determine the mass of the test sample.
A.4  Calculate the pre-dried moisture content, w , expressed as a percentage by mass, of the test sample using
p
equation (A.1).
mm''−
12
w = ×100 (A.1)
p
m'
1
where
m' is the initial mass, in grams, of the test sample;
1
m' is the mass, in grams, of the test sample after pre-drying.
2
A.5  Prepare the test portions for moisture measurement from the pre-dried sample according to the procedure in
ISO 3082.
A.6  Determine the drying loss of the test portion in accordance with 7.2 and calculate the addition
...