EP 0621915 B1 19970416 - BLEACHING OF CHEMICAL PULP

Title (en)

BLEACHING OF CHEMICAL PULP

Title (de)

BLEICHEN VON CHEMISCHEM ZELLSTOFF

Title (fr)

BLANCHIMENT DE PATE CHIMIQUE

Publication

EP 0621915 B1 19970416 (EN)

Application

EP 93902618 A 19930112

Priority

SE 9200152 A 19920121
SE 9300012 W 19930112

Abstract (en)

[origin: WO9314262A1] A method of bleaching sulphate pulp without using chlorine-containing bleaching agents. The sulphate pulp is oxygen delignified and can possibly also be ozone delignified to a kappa number below 9.5. Thereafter a pretreatment with complexing agent is carried out for 1-60 minutes, at which the pulp consistency is 1-15 %, the temperature 70-110 DEG C and pH 5-7. The pulp thus pretreated is washed and dewatered to a consistency of 18-40 %. Thereafter peroxide bleaching in alkaline environment takes place in the presence of silicate or an organic complexing agent of the type phosphonic or carboxylic acid.

IPC 1-7

D21C 9/16

IPC 8 full level

D21C 9/10 (2006.01); D21C 9/147 (2006.01); D21C 9/153 (2006.01); D21C 9/16 (2006.01)

CPC (source: EP)

D21C 9/1057 (2013.01); D21C 9/147 (2013.01); D21C 9/153 (2013.01); D21C 9/163 (2013.01)

Designated contracting state (EPC)

AT DE ES FR PT SE

DOCDB simple family (publication)

WO 9314262 A1 19930722; AT E151826 T1 19970515; AU 3412593 A 19930803; AU 653467 B2 19940929; BR 9305761 A 19970128; CA 2124088 A1 19930722; DE 69309893 D1 19970522; DE 69309893 T2 19971106; EP 0621915 A1 19941102; EP 0621915 B1 19970416; ES 2102008 T3 19970716; FI 943431 A0 19940720; FI 943431 A 19940720; JP H07503042 A 19950330; NO 942718 D0 19940720; NO 942718 L 19940720; NZ 246713 A 19950427; SE 469842 B 19930927; SE 469842 C 19960115; SE 9200152 D0 19920121; SE 9200152 L 19930722; ZA 93317 B 19930819

DOCDB simple family (application)

SE 9300012 W 19930112; AT 93902618 T 19930112; AU 3412593 A 19930112; BR 9305761 A 19930112; CA 2124088 A 19930112; DE 69309893 T 19930112; EP 93902618 A 19930112; ES 93902618 T 19930112; FI 943431 A 19940720; JP 51237993 A 19930112; NO 942718 A 19940720; NZ 24671393 A 19930112; SE 9200152 A 19920121; ZA 93317 A 19930118