EP 1036237 A1 20000920 - IMPROVEMENTS TO THE BLEACHING PROCESS FOR CHEMICAL PULP AND INTERMEDIATE PULP DISPERSIONS
Title (en)
IMPROVEMENTS TO THE BLEACHING PROCESS FOR CHEMICAL PULP AND INTERMEDIATE PULP DISPERSIONS
Title (de)
BLEICHVERFAHREN FÜR CHEMISCHE PULPE UND FÜR PULPENDISPERSIONEN IN FORM EINES ZWISCHENPRODUKTES
Title (fr)
PERFECTIONNEMENTS APPORTES AU PROCEDE DE BLANCHIMENT DE LA PATE CHIMIQUE ET DISPERSIONS INTERMEDIAIRES DE PATE
Publication
Application
Priority
EP 9706696 W 19971125
Abstract (en)
[origin: WO9927178A1] The invention relates to a process for bleaching chemical pulp, comprising a alkaline oxygen delignification step and a subsequent hydrogen peroxide bleaching step and involving removal of undesirable metal ions before and/or during the peroxide bleaching step by means of a chelating agent, wherein a polyamino disuccinic acid derivative, preferably ethylenediamine disuccinate (EDDS), is used as chelating agent at a pH value above 9.5, preferably at a pH value ranging from 10 to 11. The invention also relates to intermediate pulp dispersions containing a polyamino disuccinic acid derivative, preferably ethylenediamine disuccinate (EDDS), in a concentration of 0.01 to 2.5 % w/w on dry pulp substance and at a pH value above 9.5.
IPC 1-7
IPC 8 full level
D21C 9/10 (2006.01)
CPC (source: EP)
D21C 9/1042 (2013.01)
Citation (search report)
See references of WO 9927178A1
Designated contracting state (EPC)
AT BE CH DE DK ES FI FR GB GR IE IT LI NL PT SE
DOCDB simple family (publication)
WO 9927178 A1 19990603; AU 5657098 A 19990615; CA 2310278 A1 19990603; EP 1036237 A1 20000920
DOCDB simple family (application)
EP 9706696 W 19971125; AU 5657098 A 19971125; CA 2310278 A 19971125; EP 97952831 A 19971125