A Study on the Strengthened Oxygen Delignification of NaOH-AQ Pulp of Fast Growing Poplar with Low Kappa Number

In this paper, strengthened oxygen delignification of NaOH-AQ pulp of fast growing poplar with low kappa number (Kappa number 13.5, viscosity 851ml/g, brightness 37%ISO) was introduced. By changing different conditions of strengthened oxygen delignification: alkali dosage, temperature, time, oxygen pressure and assistant agent, etc., and detecting and analyzing the pulp kappa number, viscosity, brightness and delignification of the lignin after strengthened oxygen delignification, conditions better suitable for strengthened oxygen delignification of NaOH-AQ pulp was obtained: pulp consistency 10%, alkali dosage 2.5%, H2O2 dosage 3%, MgSO4 dosage 0.5%, oxygen pressure 0.6Mp, temperature 100°C, time 60min; under the conditions, the brightness of the pulp reached 77.2%ISO , pulp viscosity was 748ml/g, the pulp yield was 95%. This provided an experimental and feasible reference for TCF bleaching of NaOH-AQ pulp of fast growing poplar with low kappa number.