EP 0720675 A1 19960710 - CHLORINE-FREE BLEACHING OF CHEMICAL PULP INVOLVING A TWO STAGE TREATMENT WITH CHELATING AGENT
Title (en)
CHLORINE-FREE BLEACHING OF CHEMICAL PULP INVOLVING A TWO STAGE TREATMENT WITH CHELATING AGENT
Title (de)
CHLORFREIES BLEICHEN VON CHEMISCHEM ZELLSTOFF DURCH EINE ZWEISTUFFENBEHANDLUNG MIT EINEM CHELIERUNGSMITTEL
Title (fr)
BLANCHIMENT DE LA PATE CHIMIQUE SANS CHLORE IMPLIQUANT UN TRAITEMENT EN DEUX PHASES AU MOYEN D'UN AGENT DE CHELATION
Publication
Application
Priority
- SE 9400758 W 19940822
- SE 9303066 A 19930921
Abstract (en)
[origin: WO9508666A1] A method for bleaching lignocellulose-containing fiber material in the form of chemical pulp without using chloric bleaching agents where the pulp is treated with chelating agent and is bleached with ozone and peroxide. Immediately after the ozone bleaching the pulp is treated with chelating agent in a second chelating step at a pulp concentration of 1-10 % for 1-30 minutes at the temperature of 20-90 DEG C and the pH value 1,5-5. The pulp thus treated is washed and dewatered to a concentration of 8-40 % prior to the peroxide bleaching.
IPC 1-7
IPC 8 full level
D21C 9/10 (2006.01); D21C 9/153 (2006.01); D21C 9/16 (2006.01)
CPC (source: EP)
D21C 9/1042 (2013.01); D21C 9/153 (2013.01); D21C 9/163 (2013.01)
Citation (search report)
See references of WO 9508666A1
Designated contracting state (EPC)
AT DE ES FR PT SE
DOCDB simple family (publication)
WO 9508666 A1 19950330; AU 7792394 A 19950410; BR 9407555 A 19961231; CA 2168445 A1 19950330; EP 0720675 A1 19960710; FI 961279 A0 19960320; FI 961279 A 19960320; JP H09503028 A 19970325; NO 961139 D0 19960320; NO 961139 L 19960320; SE 501836 C2 19950522; SE 9303066 D0 19930921; SE 9303066 L 19950322
DOCDB simple family (application)
SE 9400758 W 19940822; AU 7792394 A 19940822; BR 9407555 A 19940822; CA 2168445 A 19940822; EP 94928521 A 19940822; FI 961279 A 19960320; JP 50971195 A 19940822; NO 961139 A 19960320; SE 9303066 A 19930921