Process for the separation of sulphides from pulping liquors using amphoteric resins
US5942084A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jan 24, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Jan 24, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/928
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A process using an amphoteric ion-exchange resin, also known as a "snake-cage polyelectrolyte" resin separates kraft white liquor into sulphide-rich and caustic-rich components. The sulphide-rich component can be used in the initial stage of pulping, pretreatment of wood chips prior to pulping, or it can be used to make polysulphide-rich liquor. The caustic-rich component can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green and polysulphide liquors into sulphide-rich and sulphide-poor components, and to remove sulphide from other mill caustic streams contaminated with sulphide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.