Process for enhanced oxygen delignification using high consistency and a split alkali addition
US5173153A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1991 |
| Grant date | Dec 22, 1992 |
| Priority date | — |
| Expiry date | Jan 3, 2011 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/147
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Unbleached pulp is combined with an aqueous alkaline solution while in a state of low consistency to distribute a first amount of alkaline material substantially uniformly throughout the pulp. The consistency of the pulp is then increased to above about 20%. Additional alkali is applied onto the high consistency pulp to provide a total amount of between 0.8 and 7% by weight of oven dry pulp. The high consistency alkali containing pulp is then treated with oxygen to effect delignification. High strength, low lignin pulps are formed which may be further bleached to high brightness with reduced amounts of chemicals by following the methods of the invention.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.