EP 0483163 A4 19920805 - ENVIRONMENTALLY IMPROVED PROCESS FOR BLEACHING LIGNOCELLULOSIC MATERIALS
Title (en)
ENVIRONMENTALLY IMPROVED PROCESS FOR BLEACHING LIGNOCELLULOSIC MATERIALS
Publication
Application
Priority
US 9002823 W 19900517
Abstract (en)
[origin: WO9118145A1] A process for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine by partially delignifying the pulp to a K No. of about 10 or less and a viscosity of greater than about 13 cps; and further delignifying the partially delignified pulp with an effective amount of ozone for a sufficient time to obtain a substantially delignified pulp having a K No. of about 5 or less, a viscosity of greater than about 10, and a GE brightness of at least about 50 %. The substantially delignified pulp may be brightened by the addition of a bleaching agent such as chlorine dioxide or a peroxide to obtain a final product having a GE brightness of at least about 65 %, preferably above 70 % to as high as 90 %. Because of the absence of elemental chlorine in this sequence, filtrate from all stages but the chlorine dioxide stage (if used) can be recovered without sewering. Major environmental improvements are thus achieved.
IPC 1-7
IPC 8 full level
D21C 3/26 (2006.01); D21C 9/00 (2006.01); D21C 9/10 (2006.01); D21C 9/14 (2006.01); D21C 9/147 (2006.01); D21C 9/153 (2006.01); D21C 9/16 (2006.01)
IPC 8 main group level
D21C (2006.01)
CPC (source: EP KR SE)
D21C 9/1057 (2013.01 - EP); D21C 9/147 (2013.01 - EP KR); D21C 9/153 (2013.01 - EP SE)
Citation (search report)
[AD] US 4619733 A 19861028 - KOOI BOON-LAM [CA]
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB IT LI LU NL SE
DOCDB simple family (publication)
WO 9118145 A1 19911128; AT E122421 T1 19950515; AU 5676890 A 19911210; AU 638017 B2 19930617; BR 9007533 A 19920428; CA 2063591 A1 19911118; CA 2063591 C 19980203; CN 1043798 C 19990623; CN 1069304 A 19930224; DE 69019350 D1 19950614; DE 69019350 T2 19960215; EP 0483163 A1 19920506; EP 0483163 A4 19920805; EP 0483163 B1 19950510; ES 2073027 T3 19950801; JP 2825346 B2 19981118; JP H05500243 A 19930121; KR 920703922 A 19921218; NO 300929 B1 19970818; NO 920217 D0 19920116; NO 920217 L 19920305; PT 98487 A 19930129; PT 98487 B 19980630; RU 2102547 C1 19980120; SE 9200107 D0 19920115; SE 9200107 L 19920313; ZA 915969 B 19920429
DOCDB simple family (application)
US 9002823 W 19900517; AT 90908787 T 19900517; AU 5676890 A 19900517; BR 9007533 A 19900517; CA 2063591 A 19900517; CN 91108650 A 19910807; DE 69019350 T 19900517; EP 90908787 A 19900517; ES 90908787 T 19900517; JP 50826990 A 19900517; KR 920700104 A 19920117; NO 920217 A 19920116; PT 9848791 A 19910729; SE 9200107 A 19920115; SU 5011189 A 19900517; ZA 915969 A 19910730