BS ISO 3260:2015 pdf download – Pulps — Determination of chlorine consumption (Degree of delignification).
1 Scope This International Standard specifies a method for the determination of the degree of delignification of pulp by measuring its chlorine consumption. This method is applicable to all kinds of pulp. 2 Normative references The following referenced documents are indispensable for the application of this document. 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 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 chlorine consumption of a pulp amount of active chlorine consumed by a pulp under the conditions specified in this International Standard Note 1 to entry: The chlorine consumption of a pulp is expressed as a percentage by mass. 4 Principle Treatment of a test portion of pulp for 15 min, at room temperature of 25 °C ± 1 °C, with chlorine generated by acidification of a sodium hypochlorite solution. Determination of the residual chlorine, which shall be more than 50 % of the amount added (see the note in Clause 9), by iodometric titration. Correction of the chlorine consumption so obtained to the consumption at constant concentration of available chlorine.
6 Apparatus Ordinary laboratory apparatus, and 6.1 High-speed wet disintegration apparatus, for example a kitchen mixer or similar apparatus which disintegrates the pulp completely with a minimum of damage to the fibres. 6.2 Apparatus for the determination of chlorine consumption, as shown in Figure 1, consisting of the following. 6.2.1 Thick-walled conical flask (D), of capacity 750 ml, with a standard ground joint (C). 6.2.2 Separating funnel (E), of capacity 50 ml to 100 ml, with standard ground joints (B and C) and a glass stopper (A). 6.3 Motor-driven coated magnetic stirrer, providing efficient stirring when the magnet and the motor table are approximately 40 mm apart. 6.4 Water bath, capable of maintaining a temperature of 25 °C ± 1 °C for at least 20 min and provided with a support for the flask. 6.5 Vacuum-pump. 6.6 Stop-watch.