Method of papermaking having zero liquid discharge
US6071380A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 9, 1998 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Mar 9, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/64
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method of papermaking having zero liquid discharge. A pulp slurry is produced from recycled cellulosic material and the slurry contains suspended cellulosic fiber material, solid contaminants and dissolved water soluble solids. The pulp slurry is subjected to a cleaning operation to produce a first flow stream containing the cellulosic fiber material and dissolved solids and a second flow stream containing dissolved solids along with solid contaminants. The first flow stream is washed with water to remove a substantial portion of the dissolved solids and provide a washed pulp which is used in a papermaking machine to produce a paper sheet. The second flow stream from the cleaning operation is compacted to produce a solid residue that can be landfilled and a liquid residue containing dissolved solids that can be recycled to the pulp cleaning operation. In a modified form of the invention, the liquid residue from the compaction can be subjected to a process, such as evaporation, to provide a solid residue and a purified water or condensate which can be used in the papermaking machine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.