EP 0561786 A4 19951115 - BLEACHING CHEMICAL PULP USING CHLORINE/CHLORINE DIOXIDE THEN OZONE
Title (en)
BLEACHING CHEMICAL PULP USING CHLORINE/CHLORINE DIOXIDE THEN OZONE
Publication
Application
Priority
- US 9105834 W 19910814
- US 56740990 A 19900814
Abstract (en)
[origin: WO9203609A1] The present invention provides for improvements in the preparation of chemical cellulosic wood pulp for use in papermaking, and specifically to enhancement of the quality of a kraft pulp which has been subjected to a chlorine dioxide/chlorine bleaching stage and thereafter subjected to ozonation prior to an extraction stage in the bleaching sequence. The improved pulp of the present invention exhibits reduced total organically bound chlorine residues in the wood pulp and adsorbed organic halides (AOX) in the effluent, and has good brightness and viscosity. The advantages of the present invention may be accomplished by means of a bleaching sequence that employs a minimum of stages, namely (D->C)ZED or DcZED with attendant relatively lower capital investment than heretofore possible.
IPC 1-7
IPC 8 full level
D21C 9/10 (2006.01); D21C 9/12 (2006.01); D21C 9/14 (2006.01); D21C 9/153 (2006.01)
CPC (source: EP)
D21C 9/1057 (2013.01); D21C 9/14 (2013.01); D21C 9/144 (2013.01); D21C 9/153 (2013.01)
Citation (search report)
- [PX] WO 9013705 A1 19901115 - INT PAPER CO [US]
- See references of WO 9203609A1
Designated contracting state (EPC)
DE ES FR SE
DOCDB simple family (publication)
WO 9203609 A1 19920305; CA 2089477 A1 19920215; DE 69128287 D1 19980108; DE 69128287 T2 19980319; EP 0561786 A1 19930929; EP 0561786 A4 19951115; EP 0561786 B1 19971126; ES 2109273 T3 19980116; FI 930625 A0 19930212; FI 930625 A 19930325; JP 3093263 B2 20001003; JP H06503857 A 19940428
DOCDB simple family (application)
US 9105834 W 19910814; CA 2089477 A 19910814; DE 69128287 T 19910814; EP 91916878 A 19910814; ES 91916878 T 19910814; FI 930625 A 19930212; JP 51585791 A 19910814