EP 0770158 B1 19981021 - METHOD FOR BLEACHING WOOD PULP USING HYDROGEN PEROXIDE
Title (en)
METHOD FOR BLEACHING WOOD PULP USING HYDROGEN PEROXIDE
Title (de)
VERFAHREN ZUM BLEICHEN VON HOLZZELLSTOFF MITTELS WASSERSTOFFPEROXID
Title (fr)
PROCEDE DE BLANCHIMENT DE PATE DE BOIS AU PEROXYDE D'HYDROGENE
Publication
Application
Priority
- US 9508152 W 19950628
- US 27355694 A 19940711
Abstract (en)
[origin: WO9601922A1] A method for bleaching wood pulp using a hydrogen peroxide solution as a bleaching agent, utilizes a two phase reaction, viz. a short high temperature phase followed by a longer second phase to consume virtually all the hydrogen peroxide remaining after the short phase. The method includes the steps of introducing pulp (10), at a consistency of 10-18 %, to a mixer (100) in which the pulp is heated to a temperature between 80 and 100 DEG C; adding sufficient sodium hydroxide (15) to bring the pulp to a pH of 9.5-11.5; adding sufficient hydrogen peroxide (35) to provide a peroxide residual after the first reactor column; passing the pulp through a reactor column (400) at a rate providing a reaction time on the column of between 5 to 60 minutes; introducing the pulp to a mixer (500) and reactivating residual hydrogen peroxide by bringing the pulp to a pH of at least 9; and depositing the pulp in a reaction tower (600) and allowing the reaction to proceed for 1-4 hours until a substantial portion of the residual hydrogen peroxide has been consumed.
IPC 1-7
IPC 8 full level
CPC (source: EP)
D21C 9/1026 (2013.01); D21C 9/163 (2013.01)
Designated contracting state (EPC)
AT DE ES PT SE
DOCDB simple family (publication)
WO 9601922 A1 19960125; AT E172504 T1 19981115; BR 9508390 A 19971028; CA 2194881 A1 19960125; DE 69505536 D1 19981126; EP 0770158 A1 19970502; EP 0770158 B1 19981021; FI 970106 A0 19970110; FI 970106 A 19970110; JP H09508184 A 19970819; ZA 955190 B 19960314
DOCDB simple family (application)
US 9508152 W 19950628; AT 95925355 T 19950628; BR 9508390 A 19950628; CA 2194881 A 19950628; DE 69505536 T 19950628; EP 95925355 A 19950628; FI 970106 A 19970110; JP 50433296 A 19950628; ZA 955190 A 19950622