DQP BLEACHING OF EUCALYPTUS UROPHYLLA ×EUCALYPTUS GR ANDIS LH 107 OXYGEN DELIGNIFIED KRAFT PULP

On the basis of optimum variables of parameters was determined that there was operating conditions was achived as follows for DQP bleaching of E. urophylla ×E. grandis LH 107 oxygen delignified kraft pulp: GIF pretreatment stage: 80 °C, 5.0 h, 1.2 % NaOH (o.d.p.), 1.4 % H2O2 (o.d.p.), 0.06 % CuSO 4 (o.d.p.), 2.8 % pyridine (o.d.p.), 0.2 MPa O 2, 5 % pulp consistency; Co-salen pretreatment stage: 70 °C, 5.0 h, 3 % NaOH (o.d.p.), 1.5 % H 2O2 (o.d.p.), 0.03 % Co-salen(o.d.p.), 1:1 pyridine/Co-salen (molar ratio), 0.2 MPaO 2, 5 % pulp consistency; D stage: 60 °C, 0.5 h, 0.2 % ClO2 (o.d.p.), 1:3 NaOH/ClO 2 (dosage ratio), 10 % pulp consistency; Q stage: 50 °C, 1.0 h, 0.5 % DTPA (o.d.p.), 10 % pulp consistency; P stage: 90 °C, 1.5 h, 0.7 % H 2O2 (o.d.p.), 0.7 % NaOH (o.d.p.), 0.6 % Na 2SiO3 (o.d.p.), 10 % pulp consistency. The maximum increase of brightness (2.8 % ISO for GIF pretreatment; 2.2 % ISO for Cosalen pretreatment), tensile index (except for GIF biomimetic pretreatment ) and burst index was observed adding GIF and Co-salen biomimetic pretreatment to DQP.