EP 0262988 A2 19880406 - Manufacture of pulp.
Title (en)
Manufacture of pulp.
Title (de)
Herstellung einer Pulpe.
Title (fr)
Fabrication d'une pâte.
Publication
Application
Priority
NZ 21778686 A 19861002
Abstract (en)
Processes for producing pulp from lignocellulosic material in which the delignification agent comprises an alkali metal hydroxide together with a small amount of a sulphite in the range between 0.1 and 15% expressed as Na2SO3 by mass on an oven dry basis of said lignocellulose. The addition of the small amount of sulphite gives a marked improvement in both the quality of the paper produced from the pulp and the rate of delignification. The rate of delignification is improved further by the use of a redox agent such as anthraquinone, anthrahydroquinone, homologues and derivatives thereof. Optionally, the process may be carried out in two stages, including a first stage in which lignocellulose is digested in a liquor containing between 0.1 and 15% of a sulphite, and another further stage in which said lignocellulose is digested in a liquor containing an alkali metal hydroxide. The pulping liquors may also contain other alkaline compounds such as sodium carbonate which act as buffers.
IPC 1-7
IPC 8 full level
CPC (source: EP)
D21C 3/022 (2013.01); D21C 3/222 (2013.01)
Designated contracting state (EPC)
AT BE CH DE ES FR GB GR IT LI LU NL SE
DOCDB simple family (publication)
EP 0262988 A2 19880406; EP 0262988 A3 19880629; BR 8705254 A 19880524; FI 874289 A0 19870930; FI 874289 A 19880403; PT 85862 A 19871101; PT 85862 B 19900112; ZA 877379 B 19890426
DOCDB simple family (application)
EP 87308780 A 19871002; BR 8705254 A 19871002; FI 874289 A 19870930; PT 8586287 A 19871002; ZA 877379 A 19870930