The peroxide bleaching of neutro-sulfite reed pulp

摘要

The peroxide bleaching of neutro-sulfite reed pulp was studied in the paper. The result showed that for the removal of lignin and bleaching effect peracetic acid (Pa) bleaching is superior to the acidic hydrogen peroxide bleaching with Na{sub}2MoO{sub}4 as catalyst. The suitable condition of Pa stage is: 1.2% CH{sub}3 COOOH, pH7.0, 70°C, 12% pulp consistency, 30 min. The condition of the subsequent treatment is: 2%H{sub}2O{sub}2, 1% Na{sub}2 SiO{sub}3, 0.2% MgSO{sub}4, NaOH/H{sub}2O{sub}2=1.8, 12% pulp consistency, 70°C, 120 min. Multistage bleaching Q-Pa-P-P is superior to Q-P-Pa-P (Q stage condition: 0.4% DTPA, normal temperature, and 30 min). Neutro-sulfite reed pulp can be bleached to a high brightness of 81% with a Q-Pa-P-P sequence.