| 摘要 |
PCT No. PCT/EP97/04758 Sec. 371 Date Apr. 15, 1999 Sec. 102(e) Date Apr. 15, 1999 PCT Filed Aug. 23, 1997 PCT Pub. No. WO98/11295 PCT Pub. Date Mar. 19, 1998A process for the delignification and bleaching of chemical pulp utilizes an acid treatment stage aimed at reducing the quantity of hexene uronic acids present in the pulp by at least 30%, and a pH adjustment stage of the pulp aimed at depositing or redepositing ions of alkaline-earth metals on the fibres of the pulp. The process further includes a washing stage of the pulp and a treatment stage of the pulp with an oxidizing agent. A chelating agent is added to the pulp before and/or during the acid treatment stage and/or before or during the pH adjustment stage or between the pH adjustment stage and washing stage. |
