Bleaching process of chemical pulp
US8128784B2 · kind B2 · utility
2Cited by
7References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2007 |
| Grant date | Mar 6, 2012 |
| Priority date | — |
| Expiry date | Apr 27, 2028 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/1042
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A process for the bleaching of chemical pulp, comprising a first chlorine dioxide treatment (D) of the initial bleaching and chelation (Q) to be carried out in connection therewith, forming together a DQ treatment. The process is characterized in that the chelation is carried out at the pH of from 2 to 7, and it is followed by an alkalizing stage (N) of the pulp, without intermediate washing for raising the pH of the pulp to above 7 and at most to 12 prior to a following stage which is a washing step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.