Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 18) (First Revision) which is identical with ISO 3260 : 2015 ‘Pulps — Determination of chlorine consumption (Degree of delignification)’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on recommendation of the Paper and Its Products Sectional Committee and approval of the Chemical Division Council.

This standard was originally published in 1979 which was based on ISO 3260 : 1975 ‘Pulps — Determination of chlorine consumption (Degree of delignification)’. The first revision of this standard has been undertaken to align it with the latest version of ISO 3260 : 2015.

The method given in this standard for measuring the degree of delignification of pulp by measuring its chlorine consumption under specified conditions is related to that for determining the degree of delignification of pulp by measuring its potassium permanganate consumption under specified conditions, given in IS 6213 (Part 10). Unlike that method, the method for the determination of chlorine consumption has the merit of not being restricted to pulps obtained in yields under 60 percent.

It has been found experimentally that there is a linear relationship between the chlorine consumption and the total lignin content of pulp. This relationship is independent of the method used in the manufacture of pulp.

The text of the ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.