EP 0208625 B1 19880217 - TREATMENT OF CHEMICAL PULPS WITH HYDROGEN PEROXIDE IN ORDER TO BLEACH THEM
Title (en)
TREATMENT OF CHEMICAL PULPS WITH HYDROGEN PEROXIDE IN ORDER TO BLEACH THEM
Publication
Application
Priority
FR 8508291 A 19850529
Abstract (en)
[origin: ES8802336A1] A two-stage hydrogen peroxide bleaching treatment of chemical pulp at a temperature of about 90 DEG -100 DEG C. comprising subjecting said pulp in a first stage to hydrogen peroxide and to at least about 3 grams/1 of bath of a metal ion sequestering agent selected from nitrogen containing sequestering agents or agents derived from polyphosphoric or polyphosphonic acids at a pH of 8.5 to 9.5 so that hydrogen peroxide of about 0.3 to 2.5 wt. % relative to dry pulp weight is consumed, and subjecting said pulp in a second stage to hydrogen peroxide and to at least about 3x10-3 gram-atoms per 100 grams of dry pulp of magnesium in the form of magnesium hydroxide and a pH of at least about 11 so that about 2 to 5 weight % of hydrogen peroxide per weight of dry pulp is consumed during the two stages.
IPC 1-7
IPC 8 full level
CPC (source: EP US)
D21C 9/163 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE DE FR IT SE
DOCDB simple family (publication)
EP 0208625 A1 19870114; EP 0208625 B1 19880217; AT E32534 T1 19880315; AU 5794486 A 19861204; CA 1273756 A 19900911; DE 3660024 D1 19880324; ES 555395 A0 19870501; ES 8802336 A1 19870501; FI 83239 B 19910228; FI 83239 C 19910610; FI 862257 A0 19860528; FI 862257 A 19861130; FR 2582692 A1 19861205; FR 2582692 B1 19871211; JP H0156194 B2 19891129; JP S61275491 A 19861205; US 4734161 A 19880329
DOCDB simple family (application)
EP 86420138 A 19860527; AT 86420138 T 19860527; AU 5794486 A 19860527; CA 508344 A 19860505; DE 3660024 T 19860527; ES 555395 A 19860528; FI 862257 A 19860528; FR 8508291 A 19850529; JP 12460086 A 19860529; US 84915786 A 19860407