ISO 5074:1994
(Main)Hard coal — Determination of Hardgrove grindability index
Hard coal — Determination of Hardgrove grindability index
Cancels and replaces the first edition (1980). Specifies the method for determining the grindability index of hard coal using the Hardgrove machine. Also specifies the procedure for calibrating the test machine and for preparing the standard reference coal samples.
Houille — Détermination de l'indice de broyabilité Hardgrove
Črni premog - Določanje meljivosti - Hardgroveov indeks
General Information
Relations
Standards Content (Sample)
INTERNATIONAL
ISO
STANDARD
5074
Second edition
1994-12-15
Hard coal - Determination of Hardgrove
grindability index
Houille - Dhermination de I ’indice de broyabilite Hardgrove
Reference number
ISO 5074:1994( E)
---------------------- Page: 1 ----------------------
ISO 5074: 1994(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. Esch 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 5074 was prepared by Technical Committee
ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods of
analysis.
This second edition cancels and replaces the first edition
(ISO 5074:1980), which has been technically revised.
Annexes A and B form an integral patt of this International Standard. An-
nex C is for information only.
0 ISO 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
---------------------- Page: 2 ----------------------
Q ISO ISO 5074: 1994(E)
Introduction
The Hardgrove grindability test and test machinery are designed and de-
veloped to characterize the relative grindability of coals. The Hardgrove
grindability index represents a composite physico-mechanical property of
the coal, embracing a number of specific properties such as hardness,
strength, tenacity and fracture, and is a function primarily of coal rank and
secondarily of coal type. Two of the important variables that tan influence
the result of this determination are the method of Sample preparation
which involves selective grinding of the coal, and the moisture content of
the coal. The Hardgrove grindability index is used empirically to estimate
the capacity and power consumption of a pulverizer, given a specified
product fineness.
---------------------- Page: 3 ----------------------
This page i ntention ally left blank
---------------------- Page: 4 ----------------------
ISO 5074:1994(E)
INTERNATIONAL STANDARD 0 ISO
- Determination of Hardgrove grindability
Hard coal
index
4 Principle
1 Scope
Treatment of a prepared Sample of coal of limited size
This International Standard specifies the method for
range under defined conditions in a laboratory appar-
determining the grindability index of hard coaP using
atus of standardized design (calibrated Hardgrove
lt also specifies the pro-
the Hardgrove machine.
machine). Derivation of the grindability index from
cedure for calibrating the test machine and for pre-
sieve analysis of the ground product and by reference
paring the Standard reference coal samples.
to a calibration Chart prepared from Standard refer-
ence material.
2 Normative references
5 Apparatus
The following Standards contain provisions which,
5.1 Balance, capable of weighing up to 100 g to an
through reference in this text, constitute provisions
accuracy of 0,Ol g.
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
5.2 Balance, capable of weighing up to 1 500 g to
are subject to revision, and Parties to agreements
an accuracy of 1 g.
based on this International Standard are encouraged
to investigate the possibility of applying the most re-
5.3 Sample divider, as specified in A.6.3 of
cent editions of the Standards indicated below.
ISO 1988:1975.
Members of IEC and ISO maintain registers of cur-
rently valid International Standards.
5.4 Crusher, a laboratory crusher capable of reduc-
ing 4,75 mm coal particles to 1,2 mm with the pro-
ISO 1988:1975, Hard coal - Sampling.
duction of a minimum of material finer than 600 Pm.
ISO 331 O-l : 1990, Test sieves - Technical require- In the case of a plate mill, the plates shall be serrated
Part 7: Test sieves of metal
ments and testing - and about 100 mm in diameter, the distance between
wire clo th. the plates being adjustable and the relative frequency
of rotation of the plates not exceeding 200 min- ‘.
Roll mills or hammer mills shall not be used.
3 Definition
5.5 Sieves
For the purposes of this International Standard, the
5.5.1 Wire-cloth test sieves, complying with the
following definition applies.
requirements of ISO 331 O-l, Series R 40/3, of aper-
ture sizes 1 ,18 mm, 600 Pm and 75 Pm respectively,
and having a cover and receiver of diameter about
3.1 hard coal: Coal having a gross calorific value of
200 mm.
more than 24 MJ/kg on a moist, ash-free basis.
1) In this International Standard, the term “hard coal” is used as an indication of maturity or rank in the coalification sequence
and is not related to the physical properties of the coal.
---------------------- Page: 5 ----------------------
0 ISO
ISO 5074: 1994(E)
5.5.2 Protective sieve, with round or Square aper-
6 Sampling
tures in the range 6 mm to 19 mm, capable of nesting
in the test sieves. A plate sieve with round holes is The gross Sample shall be collected and prepared in
accordance with the requirements of ISO 1988, ex-
recommended; if a Standard wire cloth sieve is used,
cept that the initial crushing shall be up to 4,75 mm
it may become distorted through use as a protective
instead of up to 10 mm. The gross Sample shall be
sieve and should, therefore, be marked as unsuitable
reduced to a final Sample of about 1 kg by using a
for test sieving.
Sample divider (5.3) of suitable size and capacity.
NOTE 2
Initial crushing should be performed by a mill
5.6 Mechanical sieving machine, capable of ac-
that does not produce too much fine material which could
lead to bias.
cepting an assembly of vertically nested sieves and a
cover and receiver of diameter about 200 mm. The
machine shall be able to simulate the motions of hand
7 Preparation of test Sample
sieving. This may be achieved by imparting a horizon-
tal oscillatory motion of amplitude 25 mm to 30 mm
7.1 Air-dry the final Sample (see ISO 1988) and de-
at a frequency of approximately 300 min- ‘, whilst
termine the mass of the dried Sample to the nearest
striking the top of the oscillating assembly with a
gram.
mass of 1,9 kg, moving through a vertical distance of
about 25 mm under the influence of gravity, at a fre-
Since the Hardgrove grindability index, especially for
quency of approximately 150 blows per minute.
coals with a high content of inherent moisture, varies
depending on the moisture content of the coal, air-
Alternatively, the nest of sieves, cover and receiver
drying should take place at a relative humidity of
may be vibrated by an electromagnetic device, pro-
30 % to 70 %. If this has not been done, a determi-
vided the sieving performante is equivalent to the
nation of the moisture content of the air-dried Sample
mechanically vibrated machine described.
shall be made, and the result shall be reported.
Sieve the dried Sample on a nest of sieves consisting
of a 1 ,18 mm aperture sieve on top of a 600 Pm ap-
5.7 Hardgrove grindability machine, as shown in
erture sieve, by sieving batches of about 200 g for
figure 1 and with the essential tolerantes shown in
2 min in the sieving machine, followed by gentle
figure2. lt includes a stationary grinding bowl, of
brushing of the oversize material with a soft brush
hardened iron or steel, with a horizontal track in which
(5.8) to assist the passage through the sieve. Crush
run eight steel balls, each of diameter 25,4 mm. The
the material retained on the 1 ,18 mm sieve with the
balls shall be driven by an upper grinding ring rotated
crusher (5.4) adjusted so that only the largest particles
at 20 r/min + 1 r/min. The upper grinding ring, which
are crushed; sieve the crushed material for 3 min and
shall be of similar material to the bowl, shall be con-
return the oversize material to the crusher again, re-
nected to a spindle and shall be driven by an electric
adjust to crush only the largest particles. Continue
motor through reduction gears. A load shall be added
crushing and sieving until all the material Passes
to the spindle so that the total vet-tical forte on the
through the 1,18 mm sieve.
balls due to the top ring, gear, load and spindle is
284 N + 2 N, i.e. closely equivalent to a total mass
-
7.2 Discard that part of the Portion passing through
of 29 kg + 0,2 kg. The machine shall be fitted with a
-
the 600 Fm sieve and weigh, to the nearest gram, the
revolution counter and an automatic device for
coal passing through the 1,18 mm sieve and retained
stopping the machine after 60 + - 0,25 revolutions. lt
on the 600 Pm sieve. If the yield in this size range is
shall be calibrated by the method described in
less than 50 % of the dried Sample, the coal thus
clause 8, before use for the determination of
prepared shall be discarded and another final Sample
Hardgrove indices.
of about 1 kg shall be taken from the gross Sample
and the Sample preparation repeated.
NOTE 1 The grinding
...
SLOVENSKI STANDARD
SIST ISO 5074:1998
01-februar-1998
ýUQLSUHPRJ'RORþDQMHPHOMLYRVWL+DUGJURYHRYLQGHNV
Hard coal -- Determination of Hardgrove grindability index
Houille -- Détermination de l'indice de broyabilité Hardgrove
Ta slovenski standard je istoveten z: ISO 5074:1994
ICS:
73.040 Premogi Coals
SIST ISO 5074:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 5074:1998
---------------------- Page: 2 ----------------------
SIST ISO 5074:1998
INTERNATIONAL
ISO
STANDARD
5074
Second edition
1994-12-15
Hard coal - Determination of Hardgrove
grindability index
Houille - Dhermination de I ’indice de broyabilite Hardgrove
Reference number
ISO 5074:1994( E)
---------------------- Page: 3 ----------------------
SIST ISO 5074:1998
ISO 5074: 1994(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. Esch 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 5074 was prepared by Technical Committee
ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods of
analysis.
This second edition cancels and replaces the first edition
(ISO 5074:1980), which has been technically revised.
Annexes A and B form an integral patt of this International Standard. An-
nex C is for information only.
0 ISO 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
---------------------- Page: 4 ----------------------
SIST ISO 5074:1998
Q ISO ISO 5074: 1994(E)
Introduction
The Hardgrove grindability test and test machinery are designed and de-
veloped to characterize the relative grindability of coals. The Hardgrove
grindability index represents a composite physico-mechanical property of
the coal, embracing a number of specific properties such as hardness,
strength, tenacity and fracture, and is a function primarily of coal rank and
secondarily of coal type. Two of the important variables that tan influence
the result of this determination are the method of Sample preparation
which involves selective grinding of the coal, and the moisture content of
the coal. The Hardgrove grindability index is used empirically to estimate
the capacity and power consumption of a pulverizer, given a specified
product fineness.
---------------------- Page: 5 ----------------------
SIST ISO 5074:1998
This page i ntention ally left blank
---------------------- Page: 6 ----------------------
SIST ISO 5074:1998
ISO 5074:1994(E)
INTERNATIONAL STANDARD 0 ISO
- Determination of Hardgrove grindability
Hard coal
index
4 Principle
1 Scope
Treatment of a prepared Sample of coal of limited size
This International Standard specifies the method for
range under defined conditions in a laboratory appar-
determining the grindability index of hard coaP using
atus of standardized design (calibrated Hardgrove
lt also specifies the pro-
the Hardgrove machine.
machine). Derivation of the grindability index from
cedure for calibrating the test machine and for pre-
sieve analysis of the ground product and by reference
paring the Standard reference coal samples.
to a calibration Chart prepared from Standard refer-
ence material.
2 Normative references
5 Apparatus
The following Standards contain provisions which,
5.1 Balance, capable of weighing up to 100 g to an
through reference in this text, constitute provisions
accuracy of 0,Ol g.
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
5.2 Balance, capable of weighing up to 1 500 g to
are subject to revision, and Parties to agreements
an accuracy of 1 g.
based on this International Standard are encouraged
to investigate the possibility of applying the most re-
5.3 Sample divider, as specified in A.6.3 of
cent editions of the Standards indicated below.
ISO 1988:1975.
Members of IEC and ISO maintain registers of cur-
rently valid International Standards.
5.4 Crusher, a laboratory crusher capable of reduc-
ing 4,75 mm coal particles to 1,2 mm with the pro-
ISO 1988:1975, Hard coal - Sampling.
duction of a minimum of material finer than 600 Pm.
ISO 331 O-l : 1990, Test sieves - Technical require- In the case of a plate mill, the plates shall be serrated
Part 7: Test sieves of metal
ments and testing - and about 100 mm in diameter, the distance between
wire clo th. the plates being adjustable and the relative frequency
of rotation of the plates not exceeding 200 min- ‘.
Roll mills or hammer mills shall not be used.
3 Definition
5.5 Sieves
For the purposes of this International Standard, the
5.5.1 Wire-cloth test sieves, complying with the
following definition applies.
requirements of ISO 331 O-l, Series R 40/3, of aper-
ture sizes 1 ,18 mm, 600 Pm and 75 Pm respectively,
and having a cover and receiver of diameter about
3.1 hard coal: Coal having a gross calorific value of
200 mm.
more than 24 MJ/kg on a moist, ash-free basis.
1) In this International Standard, the term “hard coal” is used as an indication of maturity or rank in the coalification sequence
and is not related to the physical properties of the coal.
---------------------- Page: 7 ----------------------
SIST ISO 5074:1998
0 ISO
ISO 5074: 1994(E)
5.5.2 Protective sieve, with round or Square aper-
6 Sampling
tures in the range 6 mm to 19 mm, capable of nesting
in the test sieves. A plate sieve with round holes is The gross Sample shall be collected and prepared in
accordance with the requirements of ISO 1988, ex-
recommended; if a Standard wire cloth sieve is used,
cept that the initial crushing shall be up to 4,75 mm
it may become distorted through use as a protective
instead of up to 10 mm. The gross Sample shall be
sieve and should, therefore, be marked as unsuitable
reduced to a final Sample of about 1 kg by using a
for test sieving.
Sample divider (5.3) of suitable size and capacity.
NOTE 2
Initial crushing should be performed by a mill
5.6 Mechanical sieving machine, capable of ac-
that does not produce too much fine material which could
lead to bias.
cepting an assembly of vertically nested sieves and a
cover and receiver of diameter about 200 mm. The
machine shall be able to simulate the motions of hand
7 Preparation of test Sample
sieving. This may be achieved by imparting a horizon-
tal oscillatory motion of amplitude 25 mm to 30 mm
7.1 Air-dry the final Sample (see ISO 1988) and de-
at a frequency of approximately 300 min- ‘, whilst
termine the mass of the dried Sample to the nearest
striking the top of the oscillating assembly with a
gram.
mass of 1,9 kg, moving through a vertical distance of
about 25 mm under the influence of gravity, at a fre-
Since the Hardgrove grindability index, especially for
quency of approximately 150 blows per minute.
coals with a high content of inherent moisture, varies
depending on the moisture content of the coal, air-
Alternatively, the nest of sieves, cover and receiver
drying should take place at a relative humidity of
may be vibrated by an electromagnetic device, pro-
30 % to 70 %. If this has not been done, a determi-
vided the sieving performante is equivalent to the
nation of the moisture content of the air-dried Sample
mechanically vibrated machine described.
shall be made, and the result shall be reported.
Sieve the dried Sample on a nest of sieves consisting
of a 1 ,18 mm aperture sieve on top of a 600 Pm ap-
5.7 Hardgrove grindability machine, as shown in
erture sieve, by sieving batches of about 200 g for
figure 1 and with the essential tolerantes shown in
2 min in the sieving machine, followed by gentle
figure2. lt includes a stationary grinding bowl, of
brushing of the oversize material with a soft brush
hardened iron or steel, with a horizontal track in which
(5.8) to assist the passage through the sieve. Crush
run eight steel balls, each of diameter 25,4 mm. The
the material retained on the 1 ,18 mm sieve with the
balls shall be driven by an upper grinding ring rotated
crusher (5.4) adjusted so that only the largest particles
at 20 r/min + 1 r/min. The upper grinding ring, which
are crushed; sieve the crushed material for 3 min and
shall be of similar material to the bowl, shall be con-
return the oversize material to the crusher again, re-
nected to a spindle and shall be driven by an electric
adjust to crush only the largest particles. Continue
motor through reduction gears. A load shall be added
crushing and sieving until all the material Passes
to the spindle so that the total vet-tical forte on the
through the 1,18 mm sieve.
balls due to the top ring, gear, load and spindle is
284 N + 2 N, i.e. closely equivalent to a total mass
-
7.2 Discard that part of the Portion passing through
of 29 kg + 0,2 kg. The machine shall be fitted with a
-
the 600 Fm sieve and weigh, to the nearest gram, the
revolution counter and an automatic device for
coal passing through the 1
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.