EP 1088130 A2 20010404 - PEROXIDE, OXYGEN, AND PEROXIDE/OXYGEN BRIGHTENING OF CHEMICAL AND MIXED WASTE PULPS
Title (en)
PEROXIDE, OXYGEN, AND PEROXIDE/OXYGEN BRIGHTENING OF CHEMICAL AND MIXED WASTE PULPS
Title (de)
PEROXIDE, SAUERSTOFF, UND PEROXIDE/SAUERSTOFF BLEICHEN VON ZELLSTOFFEN UND ALTPAPIERFASERSTOFFEN
Title (fr)
ECLAIRCISSEMENT DE PATES CHIMIQUES ET DE PATES DE VIEUX PAPIERS MELANGES, AU MOYEN DE PEROXYDE, D'OXYGENE OU DE PEROXYDE/OXYGENE
Publication
Application
Priority
US 9810070 W 19980515
Abstract (en)
[origin: WO9960201A3] A composition and method for use in the peroxide, oxygen, or peroxide/oxygen stage of brightening pulps with less than 18 % lignin utilize a megnesium compound in a sodium silicate solution to form a higher percentage of high molecular weight silicates. Such high molecular weight silicates preferentially adsorb transition metal impurities which, if left in solution, would tend to decompose hydrogen peroxide and organic peroxides. Hydrogen peroxide is added to peroxide and peroxide/oxygen stages, while it is generated, along with organic peroxides, during an oxygen stage. Decomposition decreases the amount of peroxide that actually reacts with lignin and generates free radicals that attack the desired product, carbohydrate fibers. The high molecular weight silicates can be formed by using any magnesium compound which dissociates to form Mg(OH)<+> cations, which in turn cause a silicate polymerization reaction. The formation of Mg(OH)<+> cations from magnesium compounds occurs most realidy over a pH range of at least about 8 and preferably between about 8 and about 12. The magnesium compound is added in an amount to achieve an Mg:SiO2 mass ratio of between about 1:46 to about 1:2, and preferably between about 1:15 to about 1:3.
IPC 1-7
IPC 8 full level
D21C 9/10 (2006.01); D21C 9/147 (2006.01); D21C 9/16 (2006.01)
CPC (source: EP)
D21C 9/1036 (2013.01); D21C 9/147 (2013.01); D21C 9/163 (2013.01)
Designated contracting state (EPC)
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
WO 9960201 A2 19991125; WO 9960201 A3 20000803; AT E263268 T1 20040415; AU 7493898 A 19991206; CA 2332304 A1 19991125; CA 2332304 C 20050111; DE 69822893 D1 20040506; EP 1088130 A2 20010404; EP 1088130 B1 20040331; MX PA00011196 A 20030422
DOCDB simple family (application)
US 9810070 W 19980515; AT 98922379 T 19980515; AU 7493898 A 19980515; CA 2332304 A 19980515; DE 69822893 T 19980515; EP 98922379 A 19980515; MX PA00011196 A 19980515