EP 0605565 B1 19960605 - A METHOD IN OZONE BLEACHING OF PULP
Title (en)
A METHOD IN OZONE BLEACHING OF PULP
Title (de)
VERFAHREN ZUM BLEICHEN VON ZELLSTOFF MITTELS OZON
Title (fr)
PROCEDE DE BLANCHIMENT DE PATE A L'OZONE
Publication
Application
Priority
- SE 9102693 A 19910917
- SE 9200635 W 19920916
Abstract (en)
[origin: WO9306297A1] When closing the process of manufacturing cellulose pulp of high brightness, i.e. including the recovery of essentially all waste liquor, there is an untenable enrichment of certain basic elements, such as sodium and sulphur. The present invention provides a partial solution to this problem and is concerned with a method in bleaching with ozone lignocellulosic material (cellulose pulp) which has been at least partially manufactured chemically, in the presence of water at a degree of acidity, expressed as pH, of 2-5. The method is characterized in that the acidity is maintained during the ozone bleaching process by adding a sulphuric acid solution or an acid sodium sulphate solution produced by electrolysis (or electrodialysis) of an essentially neutral sodium sulphate solution obtained by recycling chemicals in a system to which rest solution (waste liquor) from the ozone bleaching process is added.
IPC 1-7
IPC 8 full level
D21C 9/153 (2006.01); D21C 11/00 (2006.01)
CPC (source: EP)
D21C 9/153 (2013.01); D21C 11/0021 (2013.01)
Designated contracting state (EPC)
AT DE ES FR
DOCDB simple family (publication)
WO 9306297 A1 19930401; AT E138989 T1 19960615; AU 2663192 A 19930427; AU 657003 B2 19950223; CA 2116974 A1 19930401; DE 69211351 D1 19960711; DE 69211351 T2 19970123; EP 0605565 A1 19940713; EP 0605565 B1 19960605; ES 2089567 T3 19961001; FI 941238 A0 19940316; FI 941238 A 19940316; PT 100870 A 19940131; PT 100870 B 19990730; SE 500053 C2 19940328; SE 9102693 D0 19910917; SE 9102693 L 19930318
DOCDB simple family (application)
SE 9200635 W 19920916; AT 92920388 T 19920916; AU 2663192 A 19920916; CA 2116974 A 19920916; DE 69211351 T 19920916; EP 92920388 A 19920916; ES 92920388 T 19920916; FI 941238 A 19940316; PT 10087092 A 19920916; SE 9102693 A 19910917