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IS0
I N T E RN AT I O N A L ORGAN I Z AT1 ON FOR STAND A RD I ZATl O N
IS0 RECOMMENDATION
R 302
DETERMINATION OF THE KAPPA NUMBER OF PULP
(DEGREE OF DELI G NI FICATION)
1st EDITION
April 1963
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The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the oniy valid standard is the national standard of that country.
in Switzerland
Printed
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 302, Determination of the Kappa Number of Pulp (Degree of
Delignification), was drawn up by Technical Committee ISO/TC 6, Paper, the Secretariat of
which is held by the Association Française de Normalisation (AFNOR).
Work on this question by the Technical Committee began in 1961 and led in the same year
to the adoption of a Draft IS0 Recommendation.
In December 1961, this Draft IS0 Recommendation (No. 492) was circulated to all the IS0
Member Bodies for enquiry. It was approved by the following Member Bodies :
Republic of South Africa
Australia Germany
Austria India Romania
Brazil Israel Spain
Bulgaria Italy Sweden
Canada Japan Switzerland
Czechoslovakia Netherlands Turkey
United Kingdom
Denmark Norway
U.S.S.R.
Finland Poland
France Portugal Yugoslavia
One Member Body opposed the approval of the Draft:
Belgium.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in April 1963, to accept it as an IS0 RECOMMENDATION.
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IS0 / R 302 - 1- (E)
IS0 Recommendation R 302 April 1963
DETERMINATION OF TKE KAPPA NCJMBER OF PULP
(DEGREE OF DELIGNEKATION)
1. SCOPE
This method applies to the determination of the relative hardness, bleachability or degree of
delignification of pulp. It may be used for all types and grades of chemical and semi-chemical,
unbleached and semi-bleached pulps obtained in yields under 60 per cent (Note I).
2. DEFINITION
The Kappa number is the number of millilitres of 0.1 N potassium permanganate solution con-
L
IS0 Recommendation by one gramme of oven-dry
sumed under the conditions specified in this
pulp. The results are corrected to 50 per cent consumption of the permanganate added.
3. APPARATUS
Agitator of propeller type, made of glass or other non-corrosive material (a plastics or glass-
3.1
covered magnetic stirrer may be used instead).
3.2 Disintegration apparatus, high speed, wet, e.g. a kitchen mixer or similar apparatus which
disintegrates the pulp completely with a minimum of damage to the fibres.
3.3 Bath capable of maintaining a constant temperature of 25.0 "C f 0.2 "C in the reaction vessel.
4. REAGENTS
4.1 Potassium permanganate solution, standardized 0.1000 N & 0.0005 N.
4.2 Sodium thiosulphate solution, ca. 0.2 N. Normality known with an accuracy of & 0.0005 N.
4.3 Potassium iodide solution, 1 .O M.
4.4 Sulphuric acid, 4.0 N.
4.5 Starch indicator solution, 0.2 per cent.
All reagents should be of analytical grade.
5. PREPARATION OF SAMPLE
5.1 Air-dried pulp sheets. Tear 3 to 10 g of the pulp into small pieces.
5.2 Screened slush pulps. Make a 3 to 10 g air-dry pad by filtering on a Buchner funnel, avoid-
ing any loss of fibres. Air-dry the pad and tear it into small pieces.
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Unscreened pulps. If the pulp sample is taken from unscreened pulp which is normally
5.3
screened before bleaching or other processing, then the shives and knots should be removed
from the sample by screening. The method of screening should be stated along with the
test results and should be chosen to give results similar to those obtained by the industrial
screening of the pulp. Complete the preparation of the screened pulps as in clause 5.2 above.
NOTES
1. Application of method
The method may be used for pulps obtained in yields up to 70 per cent, provided the pulp
has been well screened.
6. PROCEDURE
Prior to weighing the test samples, condition the samples for not less than 20 minutes in the
atmosphere near the balance.
Weigh out to the nearest 0.001 g that amount of pulp which will consume approximately 50 per
cent of the potassium permanganate solution (Note 2). The permanganate consumption should
be between 30 and 70 per cent. At the same time, weigh out a separate test sample for moisture
determination. Determine the moisture content according to IS0 Recommendation R 287*.
Disintegrate the test sample in 500 ml of distilled water until free from fibre clots and from
large fibre bundles. Avoid methods of disintegration which involve extensive cutting of the
fibres. Transfer the disintegrated test sample to a 1500 ml reaction beaker, using about
295 ml of distilled water to rinse out the app
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