EP 0263040 B1 19910109 - PROCESS FOR BLEACHING LIGNOCELLULOSIC MATERIALS
Title (en)
PROCESS FOR BLEACHING LIGNOCELLULOSIC MATERIALS
Publication
Application
Priority
FR 8613546 A 19860923
Abstract (en)
[origin: US4812206A] A process for bleaching a lignocellulosic matter in the form of a mechanical, thermomechanical, chemicomechanical or chemicothermomechanical papermaking pulp, or of wood chips while being converted into one of these pulp types by processing in a machine consisting essentially of two interpenetrating spiral surfaces wound around parallel shafts driven in synchronous rotation in the same direction inside a barrel which encloses them, and determining between upstream and downstream in the direction of forward travel of the matter a series of zones for drawing and braking the matter, which comprises combining a bleaching treatment using a reducing agent and a bleaching treatment using an oxidizing agent, characterized in that, after pretreatment using at least one metal-complexing or sequestering agent, the lignocellulosic matter undergoes a washing operation with an efficiency greater than 96% before undergoing in succession a bleaching treatment using a reducing agent at a pH of between about 8 and 12, a washing operation to remove the reducing agent and a bleaching treatment using an oxidizing agent.
IPC 1-7
IPC 8 full level
D21C 9/00 (2006.01); D21B 1/16 (2006.01); D21C 3/22 (2006.01); D21C 9/02 (2006.01); D21C 9/10 (2006.01); D21C 9/16 (2006.01)
CPC (source: EP US)
D21C 9/1057 (2013.01 - EP US)
Citation (examination)
DE 1171723 B 19640604 - MO OCH DOMSJOE AB
Designated contracting state (EPC)
ES FR SE
DOCDB simple family (publication)
EP 0263040 A1 19880406; EP 0263040 B1 19910109; CA 1302018 C 19920602; ES 2002249 A4 19880801; ES 2002249 B3 19911116; FI 86443 B 19920515; FI 86443 C 19920825; FI 874141 A0 19870922; FI 874141 A 19880324; FR 2604197 A1 19880325; FR 2604197 B1 19881118; JP H0210275 B2 19900307; JP S6399388 A 19880430; US 4812206 A 19890314
DOCDB simple family (application)
EP 87420244 A 19870918; CA 547509 A 19870922; ES 87420244 T 19870918; FI 874141 A 19870922; FR 8613546 A 19860923; JP 23858187 A 19870922; US 9976287 A 19870922