Bleaching recycled pulp with a reductive-oxidative sequence
US5464501A · kind A · utility
17Cited by
2References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1993 |
| Grant date | Nov 7, 1995 |
| Priority date | — |
| Expiry date | Dec 23, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/64
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a method of bleaching waste paper pulp. The pulp is first treated to a reductive chemical followed by acidification and washing or dewatering. The pulp is then subjected to ozone and then to hydrogen peroxide. The reductive chemical used is either formamidine sulphinic acid or sodium hydrosulfite.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.