ISO 302:2015

Pulps — Determination of Kappa number

ISO 302:2015 specifies a method for the determination of the Kappa number of pulp. The Kappa number is an indication of the lignin content or bleachability of pulp. ISO 302:2015 is applicable to all kinds of chemical pulps and semi-chemical pulps within the Kappa number range 1 to 100. For pulps with a Kappa number exceeding 100, use the chlorine-consumption procedure (ISO 3260) to describe the degree of delignification. To achieve the greatest precision and accuracy, the sample size has to be adjusted so that the consumption of permanganate falls between 20 % and 60 % of the amount added. NOTE There is no general and unambiguous relationship between the Kappa number and the lignin content of pulp. The relationship varies according to the wood species and delignification procedure. All compounds oxidized by KMnO4, not only lignin, will increase the consumption of KMnO4, and thereby increase the Kappa number.[8] If the Kappa number is to be used to derive an index of pulp lignin content, specific relationships will have to be developed for each pulp type.

Pâtes — Détermination de l'indice Kappa

Vlaknine - Določanje števila Kappa

Ta mednarodni standard opredeljuje metodo za določanje števila Kappa v vlakninah. Število Kappa je označba vsebnosti lignina ali zmožnosti beljenja vlaknin.
Ta mednarodni standard se uporablja za vse vrste kemičnih vlaknin in polkemičnih vlaknin s številom Kappa v razponu od 1 do 100. Za vlaknine s številom Kappa, ki presega 100, se za opis stopnje odstranjevanja lignina uporabi postopek porabe klora (ISO 3260).
Za doseganje največje natančnosti in točnosti mora biti velikost vzorca prilagojena tako, da je poraba permanganata med 20 % in 60 % dodane količine.
OPOMBA: Ne obstaja splošno in nedvoumno razmerje med številom Kappa in vsebnostjo lignina v vlaknini. Razmerje se razlikuje glede na vrsto lesa in postopek odstranjevanja lignina. Vse sestavine, oksidirane s KMnO4, ne le lignin, povečajo porabo KMnO4 in zato povečajo število Kappa.[8] Če se število Kappa namerava uporabiti za izpeljavo indeksa vsebnosti lignina v vlakninah, bo treba razviti posebno razmerje za vsako vrsto vlaknine.

General Information

• Status: Published
• Publication Date: 23-Jul-2015
• ICS: 85.040 - Pulps
• Technical Committee: ISO/TC 6 - Paper, board and pulps
• Drafting Committee: ISO/TC 6 - Paper, board and pulps
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 05-Jul-2021
• Ref Project: SIST ISO 302:2016 - Pulps -- Determination of Kappa number

Relations

• Revises: ISO 302:2004 - Pulps — Determination of Kappa number
• Effective Date: 17-May-2014

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 302
Third edition
2015-08-01
Pulps — Determination of Kappa
number
Pâtes — Détermination de l’indice Kappa
Reference number
ISO 302:2015(E)
©
ISO 2015

---------------------- Page: 1 ----------------------
ISO 302:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 302:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 2
6 Apparatus and equipment . 2
7 Sampling and preparation of sample . 3
7.1 Sampling . 3
7.2 Sample preparation . 3
8 Procedure. 3
8.1 General . 3
8.2 Blank . 4
8.3 Determination . 4
8.3.1 General. 4
8.3.2 Kappa number range 5 to 100 . 5
8.3.3 Kappa number range 1 to 5 . 5
8.4 Reference pulp . . 6
9 Calculations. 6
9.1 Kappa number 5 to 100 . 6
9.2 Kappa number 1 to 5 . 7
9.3 Expression of results . 8
9.4 Example of calculation . 8
10 Test report . 8
Annex A (informative) Precision .10
Bibliography .12
© ISO 2015 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 302:2015(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 6, Paper, board and pulps.
This third edition cancels and replaces the second edition (ISO 302:2004), which has been
technically revised.
iv © ISO 2015 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 302:2015(E)
Pulps — Determination of Kappa number
1 Scope
This International Standard specifies a method for the determination of the Kappa number of pulp. The
Kappa number is an indication of the lignin content or bleachability of pulp.
This International Standard is applicable to all kinds of chemical pulps and semi-chemical pulps within
the Kappa number range 1 to 100. For pulps with a Kappa number exceeding 100, use the chlorine-
consumption procedure (ISO 3260) to describe the degree of delignification.
To achieve the greatest precision and accuracy, the sample size has to be adjusted so that the
consumption of permanganate falls between 20 % and 60 % of the amount added.
NOTE There is no general and unambiguous relationship between the Kappa number and the lignin content
of pulp. The relationship varies according to the wood species and delignification procedure. All compounds
oxidized by KMnO , not only lignin, will increase the consumption of KMnO , and thereby increase the Kappa
4 4
[8]
number. If the Kappa number is to be used to derive an index of pulp lignin content, specific relationships will
have to be developed for each pulp type.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 638, Paper, board and pulps — Determination of dry matter content — Oven-drying method
ISO 7213, Pulps — Sampling for testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
oxidation capacity
relative amount of potassium permanganate reduced (expressed as MnO ) of the total oxidation capacity
2
3.2
total oxidation capacity
2+
oxidation capacity (permanganate consumption) when all permanganate is reduced into Mn
3.3
Kappa number of pulp
number of millilitres of 0,02 mol/l potassium permanganate solution consumed under the specified
conditions by one gram of pulp (calculated on an oven-dry basis)
Note 1 to entry: The results are corrected to a value corresponding to that obtained when 50 % of the total
oxidation capacity of the permanganate is consumed in the test at a temperature of 25 °C.
4 Principle
Disintegrated pulp is allowed to react with a specified amount of potassium permanganate solution
for a given time. The amount of pulp is chosen so that about 50 % of the total oxidation capacity of the
permanganate is left unconsumed at the end of the reaction time.
© ISO 2015 – All rights reserved 1

---------------------- Page: 5 ----------------------
ISO 302:2015(E)

The main reactions are as follows:
− +
Residual lignin + other oxidizable compounds + MnO + 4H → oxidized lignin + other oxidized
4
−
compounds + excess MnO + MnO + 2H O
4 2 2
− − + 2+
2MnO + 10I + 16H → 2Mn + 5I + 8H O
4 2 2
+ − 2+
MnO + 4H + 2I → Mn + 2H O + I
2 2 2
2− 2− −
2S O + I → S O + 2I
2 3 2 4 6
NOTE By theoretical calculation and experimental observation, a consumption of 60 % (mass/mass) is
actually the end point of the consumption for the permanganate ions, at which point the ions have been reduced
to MnO . Further oxidation, performed by means of MnO should be considered as “out of range”. By adding
2 2
potassium iodide solution, the reaction is terminated and the free iodine is titrated with sodium thiosulfate
solution. The value so obtained is corrected to 50 % consumption of the total oxidation capacity of permanganate.
5 Reagents and materials
Use only chemicals of recognized analytical grade and only distilled water or water of equivalent purity.
5.1 Sulfuric acid, c(H SO ) = 2,0 mol/l.
2 4
Add with caution 112 ml of sulfuric acid, H SO , of density 1,84 g/ml, to about 600 ml of water. Allow to
2 4
cool and dilute to 1 litre with water.
5.2 Potassium iodide, c(KI) = 1 mol/l.
Dissolve 166 g of potassium iodide, KI, in a 1 000 ml volumetric flask and fill up to the mark with water.
5.3 Potassium permanganate, c(KMnO ) = (0,020 ± 0,001) mol/l.
4
Dissolve 3,161 g of potassium permanganate, KMnO , in a 1 000 ml volumetric flask and fill up to the
4
mark with water.
NOTE Fresh solution is stable for at least 6 months if stored in a dark bottle.
5.4 Sodium thiosulfate, c(Na S O ) = (0,200 0 ± 0,000 5 ) mol/l.
2 2 3
Dissolve 49,65 g of sodium thiosulfate, Na S O · 5H O, in a 1 000 ml volumetric flask and fill up to the
2 2 3 2
mark with water.
5.5 Starch indicator, 2 g/l solution.
NOTE Commercially available standard solutions may be used.
6 Apparatus and equipment
Ordinary laboratory equipment and the following.
6.1 Agitator, of the propeller type, made of glass or other noncorrosive material (a plastic- or glass-
covered magnetic stirrer may be used instead).
6.2 Wet-disintegration apparatus or blender, high-speed mixer, capable of disintegrating the pulp
completely with minimum damage to the fibres.
6.3 Water bath, capable of maintaining a temperature of (25,0 ± 0,2) °C in the reaction vessel (see 8.3
regarding temperature correction).
2 © ISO 2015 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 302:2015(E)

6.4 Timing device, capable of measuring 10 min to the nearest 1 s.
NOTE Automatic Kappa number analysers can be used if they follow this International Standard and give
the same results.
7 Sampling and preparation of sample
7.1 Sampling
If the test is being made to evaluate a pulp lot, the sample shall be selected in accordance with ISO 7213.
If the test is made on another type of sample, report the source of the sample and if possible the sampling
procedure used.
Make sure that the test portions taken are representative of the pulp.
As the presence of small amounts of spent cooking liquor affects the Kappa number, ensure that the
sample is well washed.
7.2 Sample preparation
Prepare the test material according to one of the following procedures.
7.2.1 Air-dry pulp. Tear or cut the pulp into small pieces.
7.2.2 Screened slush pulp. Dewater the pulp sample by filtering on a Büchner funnel or by
centrifuging, avoiding any loss of fibres or fines. Air-dry the pulp sample, or dry it at a temperature not
exceeding 105 °C, and tear it into small pieces.
7.2.3 Unscreened pulp. If the sample is taken from unscreened pulp, which is normally screened
before bleaching or other processing, remove the shives and knots from the sample by screening. Choose
a procedure that gives results similar to those obtained by industrial screening. State the method of
screening in the test report. Continue the sample preparation as described in 7.2.2.
NOTE If the pulp sample contains a considerable amount of shives, the screening procedure may give rise to
incorrect results. A more reliable value may be obtained by defibrating the pulp sample before the determination.
State the method of defibration in the test report.
8 Procedure
8.1 General
This International Standard includes two different procedures. One is used in the Kappa number range
5 to 100 and the other in the Kappa number range 1 to 5.
The main difference between the procedures is the added amounts of pulp and of KMnO and the
4,
calculation. Due to stirring problems when determining Kappa numbers below 5, decrease the amounts
of pulp and permanganate.
Use 8.2 and 8.3 in both procedures. The separate procedures are described in 8.3.2 and 8.3.3.
Run the determination in duplicate.
NOTE Experimental work in Nordic countries has shown that the Kappa number determination according to
the procedure for Kappa number 5 to 100 gives results equivalent to those obtained by the procedure for Kappa
number 1 to 5, within the Kappa number range from 4 to 6.
© ISO 2015 – All rights reserved 3

---------------------- Page: 7 ----------------------
ISO 302:2015(E)

8.2 Blank
Carry out a blank determination using exactly the procedure described in 8.3, but without the pulp.
Read off the volume, V , to the nearest 0,1 ml, of the sodium thiosulfate (5.4) consumed at the inflection
1
point. The consumption of sodium thiosulfate s
...

SLOVENSKI STANDARD
oSIST ISO 302:2016
01-maj-2016
9ODNQLQH'RORþDQMHãWHYLOD.DSSD
Pulps -- Determination of Kappa number
Pâtes -- Détermination de l'indice Kappa
Ta slovenski standard je istoveten z: ISO 302:2015
ICS:
85.040 Vlaknine Pulps
oSIST ISO 302:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

oSIST ISO 302:2016

---------------------- Page: 2 ----------------------

oSIST ISO 302:2016
INTERNATIONAL ISO
STANDARD 302
Third edition
2015-08-01
Pulps — Determination of Kappa
number
Pâtes — Détermination de l’indice Kappa
Reference number
ISO 302:2015(E)
©
ISO 2015

---------------------- Page: 3 ----------------------

oSIST ISO 302:2016
ISO 302:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

---------------------- Page: 4 ----------------------

oSIST ISO 302:2016
ISO 302:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 2
6 Apparatus and equipment . 2
7 Sampling and preparation of sample . 3
7.1 Sampling . 3
7.2 Sample preparation . 3
8 Procedure. 3
8.1 General . 3
8.2 Blank . 4
8.3 Determination . 4
8.3.1 General. 4
8.3.2 Kappa number range 5 to 100 . 5
8.3.3 Kappa number range 1 to 5 . 5
8.4 Reference pulp . . 6
9 Calculations. 6
9.1 Kappa number 5 to 100 . 6
9.2 Kappa number 1 to 5 . 7
9.3 Expression of results . 8
9.4 Example of calculation . 8
10 Test report . 8
Annex A (informative) Precision .10
Bibliography .12
© ISO 2015 – All rights reserved iii

---------------------- Page: 5 ----------------------

oSIST ISO 302:2016
ISO 302:2015(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 6, Paper, board and pulps.
This third edition cancels and replaces the second edition (ISO 302:2004), which has been
technically revised.
iv © ISO 2015 – All rights reserved

---------------------- Page: 6 ----------------------

oSIST ISO 302:2016
INTERNATIONAL STANDARD ISO 302:2015(E)
Pulps — Determination of Kappa number
1 Scope
This International Standard specifies a method for the determination of the Kappa number of pulp. The
Kappa number is an indication of the lignin content or bleachability of pulp.
This International Standard is applicable to all kinds of chemical pulps and semi-chemical pulps within
the Kappa number range 1 to 100. For pulps with a Kappa number exceeding 100, use the chlorine-
consumption procedure (ISO 3260) to describe the degree of delignification.
To achieve the greatest precision and accuracy, the sample size has to be adjusted so that the
consumption of permanganate falls between 20 % and 60 % of the amount added.
NOTE There is no general and unambiguous relationship between the Kappa number and the lignin content
of pulp. The relationship varies according to the wood species and delignification procedure. All compounds
oxidized by KMnO , not only lignin, will increase the consumption of KMnO , and thereby increase the Kappa
4 4
[8]
number. If the Kappa number is to be used to derive an index of pulp lignin content, specific relationships will
have to be developed for each pulp type.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 638, Paper, board and pulps — Determination of dry matter content — Oven-drying method
ISO 7213, Pulps — Sampling for testing
3 Terms a nd definiti ons
For the purposes of this document, the following terms and definitions apply.
3.1
oxidation capacity
relative amount of potassium permanganate reduced (expressed as MnO ) of the total oxidation capacity
2
3.2
total oxidation capacity
2+
oxidation capacity (permanganate consumption) when all permanganate is reduced into Mn
3.3
Kappa number of pulp
number of millilitres of 0,02 mol/l potassium permanganate solution consumed under the specified
conditions by one gram of pulp (calculated on an oven-dry basis)
Note 1 to entry: The results are corrected to a value corresponding to that obtained when 50 % of the total
oxidation capacity of the permanganate is consumed in the test at a temperature of 25 °C.
4 Principle
Disintegrated pulp is allowed to react with a specified amount of potassium permanganate solution
for a given time. The amount of pulp is chosen so that about 50 % of the total oxidation capacity of the
permanganate is left unconsumed at the end of the reaction time.
© ISO 2015 – All rights reserved 1

---------------------- Page: 7 ----------------------

oSIST ISO 302:2016
ISO 302:2015(E)

The main reactions are as follows:
− +
Residual lignin + other oxidizable compounds + MnO + 4H → oxidized lignin + other oxidized
4
−
compounds + excess MnO + MnO + 2H O
4 2 2
− − + 2+
2MnO + 10I + 16H → 2Mn + 5I + 8H O
4 2 2
+ − 2+
MnO + 4H + 2I → Mn + 2H O + I
2 2 2
2− 2− −
2S O + I → S O + 2I
2 3 2 4 6
NOTE By theoretical calculation and experimental observation, a consumption of 60 % (mass/mass) is
actually the end point of the consumption for the permanganate ions, at which point the ions have been reduced
to MnO . Further oxidation, performed by means of MnO should be considered as “out of range”. By adding
2 2
potassium iodide solution, the reaction is terminated and the free iodine is titrated with sodium thiosulfate
solution. The value so obtained is corrected to 50 % consumption of the total oxidation capacity of permanganate.
5 Reagents and materials
Use only chemicals of recognized analytical grade and only distilled water or water of equivalent purity.
5.1 Sulfuric acid, c(H SO ) = 2,0 mol/l.
2 4
Add with caution 112 ml of sulfuric acid, H SO , of density 1,84 g/ml, to about 600 ml of water. Allow to
2 4
cool and dilute to 1 litre with water.
5.2 Potassium iodide, c(KI) = 1 mol/l.
Dissolve 166 g of potassium iodide, KI, in a 1 000 ml volumetric flask and fill up to the mark with water.
5.3 Potassium permanganate, c(KMnO ) = (0,020 ± 0,001) mol/l.
4
Dissolve 3,161 g of potassium permanganate, KMnO , in a 1 000 ml volumetric flask and fill up to the
4
mark with water.
NOTE Fresh solution is stable for at least 6 months if stored in a dark bottle.
5.4 Sodium thiosulfate, c(Na S O ) = (0,200 0 ± 0,000 5 ) mol/l.
2 2 3
Dissolve 49,65 g of sodium thiosulfate, Na S O · 5H O, in a 1 000 ml volumetric flask and fill up to the
2 2 3 2
mark with water.
5.5 Starch indicator, 2 g/l solution.
NOTE Commercially available standard solutions may be used.
6 Apparatus and equipment
Ordinary laboratory equipment and the following.
6.1 Agitator, of the propeller type, made of glass or other noncorrosive material (a plastic- or glass-
covered magnetic stirrer may be used instead).
6.2 Wet-disintegration apparatus or blender, high-speed mixer, capable of disintegrating the pulp
completely with minimum damage to the fibres.
6.3 Water bath, capable of maintaining a temperature of (25,0 ± 0,2) °C in the reaction vessel (see 8.3
regarding temperature correction).
2 © ISO 2015 – All rights reserved

---------------------- Page: 8 ----------------------

oSIST ISO 302:2016
ISO 302:2015(E)

6.4 Timing device, capable of measuring 10 min to the nearest 1 s.
NOTE Automatic Kappa number analysers can be used if they follow this International Standard and give
the same results.
7 Sampling and preparation of sample
7.1 Sampling
If the test is being made to evaluate a pulp lot, the sample shall be selected in accordance with ISO 7213.
If the test is made on another type of sample, report the source of the sample and if possible the sampling
procedure used.
Make sure that the test portions taken are representative of the pulp.
As the presence of small amounts of spent cooking liquor affects the Kappa number, ensure that the
sample is well washed.
7.2 Sample preparation
Prepare the test material according to one of the following procedures.
7.2.1 Air-dry pulp. Tear or cut the pulp into small pieces.
7.2.2 Screened slush pulp. Dewater the pulp sample by filtering on a Büchner funnel or by
centrifuging, avoiding any loss of fibres or fines. Air-dry the pulp sample, or dry it at a temperature not
exceeding 105 °C, and tear it into small pieces.
7.2.3 Unscreened pulp. If the sample is taken from unscreened pulp, which is normally screened
before bleaching or other processing, remove the shives and knots from the sample by screening. Choose
a procedure that gives results similar to those obtained by industrial screening. State the method of
screening in the test report. Continue the sample preparation as described in 7.2.2.
NOTE If the pulp sample contains a considerable amount of shives, the screening procedure may give rise to
incorrect results. A more reliable value may be obtained by defibrating the pulp sample before the determination.
State the method of defibration in the test report.
8 Procedure
8.1 General
This International Standard includes two different procedures. One is used in the Kappa number range
5 to 100 and the other in the Kappa number range 1 to 5.
The main difference between the procedures is the added amounts of pulp and of KMnO and the
4,
calculation. Due to stirring problems when determining Kappa numbers below 5, decrease the amounts
of pulp and permanganate.
Use 8.2 and 8.3 in both procedures. The separate procedures are described in 8.3.2 and 8.3.3.
Run the determination in duplicate.
NOTE Experimental work in Nordic countries has shown that the Kappa number determination according to
the procedure for Kappa number 5 to 100 gives results equivalent to those obtained by the procedure for Kappa
number 1 to 5, within the Kappa number range from 4 to 6.
© ISO 2015 – All rights reserved 3

---------------------- Page: 9 --------------
...

SLOVENSKI STANDARD
SIST ISO 302:2016
01-junij-2016
1DGRPHãþD
SIST ISO 302:2011
9ODNQLQH'RORþDQMHãWHYLOD.DSSD
Pulps -- Determination of Kappa number
Pâtes -- Détermination de l'indice Kappa
Ta slovenski standard je istoveten z: ISO 302:2015
ICS:
85.040 Vlaknine Pulps
SIST ISO 302:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ISO 302:2016

---------------------- Page: 2 ----------------------

SIST ISO 302:2016
INTERNATIONAL ISO
STANDARD 302
Third edition
2015-08-01
Pulps — Determination of Kappa
number
Pâtes — Détermination de l’indice Kappa
Reference number
ISO 302:2015(E)
©
ISO 2015

---------------------- Page: 3 ----------------------

SIST ISO 302:2016
ISO 302:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

---------------------- Page: 4 ----------------------

SIST ISO 302:2016
ISO 302:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 2
6 Apparatus and equipment . 2
7 Sampling and preparation of sample . 3
7.1 Sampling . 3
7.2 Sample preparation . 3
8 Procedure. 3
8.1 General . 3
8.2 Blank . 4
8.3 Determination . 4
8.3.1 General. 4
8.3.2 Kappa number range 5 to 100 . 5
8.3.3 Kappa number range 1 to 5 . 5
8.4 Reference pulp . . 6
9 Calculations. 6
9.1 Kappa number 5 to 100 . 6
9.2 Kappa number 1 to 5 . 7
9.3 Expression of results . 8
9.4 Example of calculation . 8
10 Test report . 8
Annex A (informative) Precision .10
Bibliography .12
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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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 6, Paper, board and pulps.
This third edition cancels and replaces the second edition (ISO 302:2004), which has been
technically revised.
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SIST ISO 302:2016
INTERNATIONAL STANDARD ISO 302:2015(E)
Pulps — Determination of Kappa number
1 Scope
This International Standard specifies a method for the determination of the Kappa number of pulp. The
Kappa number is an indication of the lignin content or bleachability of pulp.
This International Standard is applicable to all kinds of chemical pulps and semi-chemical pulps within
the Kappa number range 1 to 100. For pulps with a Kappa number exceeding 100, use the chlorine-
consumption procedure (ISO 3260) to describe the degree of delignification.
To achieve the greatest precision and accuracy, the sample size has to be adjusted so that the
consumption of permanganate falls between 20 % and 60 % of the amount added.
NOTE There is no general and unambiguous relationship between the Kappa number and the lignin content
of pulp. The relationship varies according to the wood species and delignification procedure. All compounds
oxidized by KMnO , not only lignin, will increase the consumption of KMnO , and thereby increase the Kappa
4 4
[8]
number. If the Kappa number is to be used to derive an index of pulp lignin content, specific relationships will
have to be developed for each pulp type.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 638, Paper, board and pulps — Determination of dry matter content — Oven-drying method
ISO 7213, Pulps — Sampling for testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
oxidation capacity
relative amount of potassium permanganate reduced (expressed as MnO ) of the total oxidation capacity
2
3.2
total oxidation capacity
2+
oxidation capacity (permanganate consumption) when all permanganate is reduced into Mn
3.3
Kappa number of pulp
number of millilitres of 0,02 mol/l potassium permanganate solution consumed under the specified
conditions by one gram of pulp (calculated on an oven-dry basis)
Note 1 to entry: The results are corrected to a value corresponding to that obtained when 50 % of the total
oxidation capacity of the permanganate is consumed in the test at a temperature of 25 °C.
4 Principle
Disintegrated pulp is allowed to react with a specified amount of potassium permanganate solution
for a given time. The amount of pulp is chosen so that about 50 % of the total oxidation capacity of the
permanganate is left unconsumed at the end of the reaction time.
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The main reactions are as follows:
− +
Residual lignin + other oxidizable compounds + MnO + 4H → oxidized lignin + other oxidized
4
−
compounds + excess MnO + MnO + 2H O
4 2 2
− − + 2+
2MnO + 10I + 16H → 2Mn + 5I + 8H O
4 2 2
+ − 2+
MnO + 4H + 2I → Mn + 2H O + I
2 2 2
2− 2− −
2S O + I → S O + 2I
2 3 2 4 6
NOTE By theoretical calculation and experimental observation, a consumption of 60 % (mass/mass) is
actually the end point of the consumption for the permanganate ions, at which point the ions have been reduced
to MnO . Further oxidation, performed by means of MnO should be considered as “out of range”. By adding
2 2
potassium iodide solution, the reaction is terminated and the free iodine is titrated with sodium thiosulfate
solution. The value so obtained is corrected to 50 % consumption of the total oxidation capacity of permanganate.
5 Reagents and materials
Use only chemicals of recognized analytical grade and only distilled water or water of equivalent purity.
5.1 Sulfuric acid, c(H SO ) = 2,0 mol/l.
2 4
Add with caution 112 ml of sulfuric acid, H SO , of density 1,84 g/ml, to about 600 ml of water. Allow to
2 4
cool and dilute to 1 litre with water.
5.2 Potassium iodide, c(KI) = 1 mol/l.
Dissolve 166 g of potassium iodide, KI, in a 1 000 ml volumetric flask and fill up to the mark with water.
5.3 Potassium permanganate, c(KMnO ) = (0,020 ± 0,001) mol/l.
4
Dissolve 3,161 g of potassium permanganate, KMnO , in a 1 000 ml volumetric flask and fill up to the
4
mark with water.
NOTE Fresh solution is stable for at least 6 months if stored in a dark bottle.
5.4 Sodium thiosulfate, c(Na S O ) = (0,200 0 ± 0,000 5 ) mol/l.
2 2 3
Dissolve 49,65 g of sodium thiosulfate, Na S O · 5H O, in a 1 000 ml volumetric flask and fill up to the
2 2 3 2
mark with water.
5.5 Starch indicator, 2 g/l solution.
NOTE Commercially available standard solutions may be used.
6 Apparatus and equipment
Ordinary laboratory equipment and the following.
6.1 Agitator, of the propeller type, made of glass or other noncorrosive material (a plastic- or glass-
covered magnetic stirrer may be used instead).
6.2 Wet-disintegration apparatus or blender, high-speed mixer, capable of disintegrating the pulp
completely with minimum damage to the fibres.
6.3 Water bath, capable of maintaining a temperature of (25,0 ± 0,2) °C in the reaction vessel (see 8.3
regarding temperature correction).
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6.4 Timing device, capable of measuring 10 min to the nearest 1 s.
NOTE Automatic Kappa number analysers can be used if they follow this International Standard and give
the same results.
7 Sampling and preparation of sample
7.1 Sampling
If the test is being made to evaluate a pulp lot, the sample shall be selected in accordance with ISO 7213.
If the test is made on another type of sample, report the source of the sample and if possible the sampling
procedure used.
Make sure that the test portions taken are representative of the pulp.
As the presence of small amounts of spent cooking liquor affects the Kappa number, ensure that the
sample is well washed.
7.2 Sample preparation
Prepare the test material according to one of the following procedures.
7.2.1 Air-dry pulp. Tear or cut the pulp into small pieces.
7.2.2 Screened slush pulp. Dewater the pulp sample by filtering on a Büchner funnel or by
centrifuging, avoiding any loss of fibres or fines. Air-dry the pulp sample, or dry it at a temperature not
exceeding 105 °C, and tear it into small pieces.
7.2.3 Unscreened pulp. If the sample is taken from unscreened pulp, which is normally screened
before bleaching or other processing, remove the shives and knots from the sample by screening. Choose
a procedure that gives results similar to those obtained by industrial screening. State the method of
screening in the test report. Continue the sample preparation as described in 7.2.2.
NOTE If the pulp sample contains a considerable amount of shives, the screening procedure may give rise to
incorrect results. A more reliable value may be obtained by defibrating the pulp sample before the determination.
State the method of defibration in the test report.
8 Procedure
8.1 General
This International Standard includes two different procedures. One is used in the Kappa number range
5 to 100 and the other in the Kappa number range 1 to 5.
The main difference between the procedures is the added amounts of pulp and of KMnO and the
4,
calculation. Due to stirring problems when determining Kappa numbers below 5, decrease the amounts
of pulp and permanganate.
Use 8.2 and 8.3 in both procedures. The separate procedures are described in 8.3.2 and 8.3.3.
Run the determination in duplicate.
NOTE Experimental work in Nordic countries has shown that the Kappa number determination according to
the procedure for Kappa number 5 to 100 gives results equivalent to those obtained by the procedure for Kappa
number 1 to 5, within the Kappa number range from 4 to 6.
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