Method for lignin separation from black liquor
US9777033B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2012 |
| Grant date | Oct 3, 2017 |
| Priority date | — |
| Expiry date | Jul 19, 2032 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P40/40
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The method is for separation of lignin from original black liquor (BLIN) that has a first precipitation phase (PR1/PR2) for precipitation of lignin by a first acidification using acidifier, CO2, at alkaline conditions, then separating a lignin cake with subsequent suspension of the lignin cake in a strong acid in order to leach out metals from the lignin followed by dewatering and obtaining a clean lignin product LP. Lignin germ particles (LG) are added to the original black liquor in the first precipitation stage, preferably between two phases in said precipitation stage, in order to increase lignin particle growth on such lignin germ particles instead of spontaneous nucleation of lignin particles in said original black liquor. This results in improved filterability in subsequent dewatering and lignin cake formation and hence an increased lignin yield.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.