Method for treatment of lignocellulosic material with chlorine
US4222818A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1978 |
| Grant date | Sep 16, 1980 |
| Priority date | — |
| Expiry date | Jul 3, 1998 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/12
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A pulp containing lignocellulosic fibers is treated with chlorine in two steps. In the first step, chlorine in the amount of 0.6-0.9 grams per gram of lignin in the fibers, is mixed in the gaseous state into the pulp and in a second step the reaction products, which contain chlorinated lignin, are removed by displacing the liquid in the pulp with a chlorine solution, the amount of active chlorine in the solution in the second step being between 0.1 and 0.3 grams per gram of the lignin initially present in the pulp. In this manner 92% delignification is achieved without any intermediate washing between the two steps and with a total amount of chlorine between 0.7 and 1.2 grams per gram of lignin. The consistency of the pulp in both steps is the same and is between 6 and 12%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.