EP 0530881 A1 19930310 - Use of wash press for pulp alkali addition process.
Title (en)
Use of wash press for pulp alkali addition process.
Title (de)
Verwendung von einer Waschpresse unter Zugabe von Alkali zum Zellstoff.
Title (fr)
Utilisation d'une presse de lavage pour un procédé d'addition d'alcali à une pâte à papier.
Publication
Application
Priority
US 74822291 A 19910814
Abstract (en)
Unbleached pulp is combined with an aqueous alkaline solution while in a state of low consistency (9) to distribute a first amount of alkaline material substantially uniformly throughout the pulp. The consistency of the pulp is then increased (12) to above about 18%, and the high consistency alkali containing pulp is then treated with oxygen (21) to effect delignification (20). Additional alkali may be applied onto the high consistency pulp prior to oxygen delignification to provide a total amount of between 0.8 and 7% by weight of oven dry pulp. The invention contemplates the use of one or more wash presses (7,30) for reducing the overall amounts of alkaline material utilized in the process. High strength, low lignin pulps (25) are subsequently formed which may be further bleached to high brightness with reduced amounts of chemicals by following the methods of the invention. <IMAGE>
IPC 1-7
IPC 8 full level
D21C 3/00 (2006.01); D21C 9/02 (2006.01); D21C 9/10 (2006.01); D21C 9/147 (2006.01)
CPC (source: EP KR)
D21C 9/02 (2013.01 - EP); D21C 9/10 (2013.01 - KR); D21C 9/1005 (2013.01 - EP); D21C 9/147 (2013.01 - EP KR)
Citation (search report)
- [AD] WO 8604938 A1 19860828 - ELTON EDWARD FRANCIS
- [AP] WO 9212288 A1 19920723 - UNION CAMP PATENT HOLDING [US]
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
EP 0530881 A1 19930310; AU 2095492 A 19930225; AU 647950 B2 19940331; BR 9203170 A 19930330; CA 2075875 A1 19930215; CN 1070969 A 19930414; FI 923585 A0 19920811; FI 923585 A 19930215; JP H05195461 A 19930803; JP H0726350 B2 19950322; KR 930004578 A 19930322; KR 950013196 B1 19951025; NO 923163 D0 19920813; NO 923163 L 19930215; SE 9202338 D0 19920812; SE 9202338 L 19930215; ZA 926092 B 19930302
DOCDB simple family (application)
EP 92202469 A 19920811; AU 2095492 A 19920812; BR 9203170 A 19920814; CA 2075875 A 19920812; CN 92110875 A 19920814; FI 923585 A 19920811; JP 21680692 A 19920814; KR 920014738 A 19920814; NO 923163 A 19920813; SE 9202338 A 19920812; ZA 926092 A 19920813