Title:
BLEACHING OF CHEMICAL PULP FOR PAPERMAKING
Document Type and Number:
Japanese Patent JP3509832
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent the environmental pollution due to wastewater from bleaching and to carry out good delignification and bleaching in the delignifying and bleaching treatments of a chemical pulp with a mixture of a peroxide with dicyandiamide in an alkaline medium after cooking treatment.
SOLUTION: A chemical pulp for papermaking is cooked or cooked and then treated with oxygen at a high temperature under a high pressure or further treated with an acid or a chelating agent or chlorine dioxide or ozone after cooking and then treated with a mixture of a peroxide such as hydrogen peroxide with dicyandiamine or delignification and bleaching treatments thereof are subsequently carried out in a system of the peroxide, dicyanediamide and oxygen in an alkaline medium such as caustic soda when delignifying and bleaching the chemical pulp. Thereby, the consumption of a chlorine-based bleaching agent is suppressed to thereby suppress the formation of an organic chlorine compound as a by-product.
Inventors:
Fukushima, Takamasa
Koshizuka, Tetsuo
Miyauchi, Takeshi
Shimada, Akiyo
Koshizuka, Tetsuo
Miyauchi, Takeshi
Shimada, Akiyo
Application Number:
JP34067295A
Publication Date:
March 22, 2004
Filing Date:
December 27, 1995
Export Citation:
Assignee:
MITSUBISHI GAS CHEM CO INC
International Classes:
D21C9/16; (IPC1-7): D21C9/16