Extended delignification during oxygen bleaching of modified kraft pulp

1986 ◽  
Vol 1 (4) ◽  
pp. 12-17
Author(s):  
Olof Samuelson ◽  
Urban Öjteg
Keyword(s):  
Kraft Pulp ◽  
Oxygen Bleaching

Activated Sludge Treatment of Kraft Mill Effluents from Conventional and Oxygen Bleaching

1991 ◽  
Vol 24 (3-4) ◽  
pp. 427-430 ◽  
Author(s):  
J. Nevalainen ◽  
P.-R. Rantala ◽  
J. Junna ◽  
R. Lammi
Keyword(s):  
Activated Sludge ◽  
Kraft Pulp ◽  
Activated Sludge Process ◽  
Chlorinated Phenols ◽  
Pulp Mills ◽  
Main Interest ◽  
Sludge Treatment ◽  
Kraft Pulp Mills ◽  
Activated Sludge Processes ◽  
Oxygen Bleaching

Conventional and oxygen bleaching effluents from hardwood kraft pulp mills were treated in laboratory-scale activated sludge processes. The main interest was the fate of organochlorine compounds in the activated sludge process. In the treatment of conventional bleaching wastewaters the BOD7-reduction was 80-91 % and in oxygen bleaching wastewaters 86-93 %. The respective CODCr removals were about 40 % and about 50 %. The AOX reductions were on average 22 % and 40 % in the treatment of conventional and oxygen bleaching effluents, respectively. The reductions of chlorinated phenols, guajacols and catecols were usually more than 50 % in both reactors. Very little accumulation of AOX into the sludge was observed. The stripping of AOX from aeration unit was insignificant.

A novel approach for the oxidative catalysis employing polyoxometalate–laccase system: application to the oxygen bleaching of kraft pulp

2004 ◽  
Vol 5 (9) ◽  
pp. 485-489 ◽  
Author(s):  
Ana P.M Tavares ◽  
Jose A.F Gamelas ◽  
Armindo R Gaspar ◽  
Dmitry V Evtuguin ◽  
Ana M.R.B Xavier
Keyword(s):  
System Application ◽  
Kraft Pulp ◽  
Novel Approach ◽  
Oxygen Bleaching ◽  
Oxidative Catalysis

Oxygen bleaching of kraft pulp with polyoxometalates and laccase applying a novel multi-stage process

2005 ◽  
Vol 33 (3-6) ◽  
pp. 57-64 ◽  
Author(s):  
Jose A.F. Gamelas ◽  
Ana P.M. Tavares ◽  
Dmitry V. Evtuguin ◽  
Ana M.B. Xavier
Keyword(s):  
Kraft Pulp ◽  
Multi Stage ◽  
Stage Process ◽  
Oxygen Bleaching

Oxygen Bleaching of Kraft Pulp 1. Role of Condensed Units

Holzforschung ◽  
1994 ◽  
Vol 48 (4) ◽  
pp. 355-359 ◽  
Author(s):  
Lai Yuan-Zong ◽  
Funaoka Masamitsu ◽  
Chen Hsin-Tai
Keyword(s):  
Kraft Pulp ◽  
Oxygen Bleaching

Oxygen bleaching of kraft pulp catalysed by Mn(III)-substituted polyoxometalates

2003 ◽  
Vol 239 (1-2) ◽  
pp. 157-168 ◽  
Author(s):  
A. Gaspar ◽  
D.V. Evtuguin ◽  
C. Pascoal Neto
Keyword(s):  
Kraft Pulp ◽  
Oxygen Bleaching

A Pretreatment with Nitrous Acid for Oxygen Bleaching of Kraft Pulp and Its Bleaching Mechanism.

1993 ◽  
Vol 47 (5) ◽  
pp. 635-644 ◽  
Author(s):  
Hiroshi Ohi ◽  
Masanao Tajiri ◽  
Yuzo Iwanaga ◽  
Masato Suzuki ◽  
Tetsuo Aoyagi ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Kraft Pulp ◽  
Oxygen Bleaching

Dissolution of Lignin in Kraft Pulp by Oxygen Bleaching

1993 ◽  
Vol 13 (2) ◽  
pp. 237-259 ◽  
Author(s):  
Per Larsson ◽  
Olof Samuelson
Keyword(s):  
Kraft Pulp ◽  
Oxygen Bleaching

Prebleaching of eucalypt kraft pulp with OP stages: Effect of an acid pretreatment or chelation step

TAPPI Journal ◽  
2012 ◽  
Vol 11 (6) ◽  
pp. 31-38
Author(s):  
TATIANA M. PÓVOAS ◽  
DINA A.G. ANGÉLICO ◽  
ANA P.V. EGAS ◽  
PEDRO E.G. LOUREIRO ◽  
LICÍNIO M. GANDO-FERREIRA ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Comparative Evaluation ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Acid Pretreatment ◽  
High Brightness ◽  
Pulp Viscosity ◽  
Brightness Reversion

We conducted a comparative evaluation of different treatments for the bleaching of eucalypt kraft pulps beginning with OP stages. The treatments tested were (1) an acid chelation stage with DTPA (OQP sequence); (2) a hot acid stage (AOP sequence); and (3) a chelant addition into the alkaline oxygen stage ((OQ)P and A(OQ)P sequences). The latter strategy was also studied for environmental reasons, as it contributes to the closure of the filtrate cycle. The OQP sequence leads to the highest brightness gain and pulp viscosity and the lowest peroxide consumption caused by an efficient metals control. Considering that the low biodegradability of the chelant is a problem, the A(OQ)P sequence is an interesting option because it leads to reduced peroxide consumption (excluding OQP) while still reaching high brightness values and similar brightness reversion to OQP prebleaching, with only a viscosity loss of 160 dm3/kg. Therefore, a hot acid stage could be considered when a separate acid Q stage is absent in a prebleaching sequence of Eucalyptus globulus kraft pulps involving OP stages.

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