| 摘要 |
The method is for bleaching cellulose pulp having an MC consistency in a first step with chlorine dioxide in a bleaching sequence with several bleaching steps. The pulp is bleached in this first chlorine dioxide step in a first phase at a lower temperature of 60±10° C. during a retention time of from 30 seconds to 30 minutes, after which the pulp is heated by at least 10° C. to a reaction temperature of 90±10° C. for a second phase, which has a retention time of 60-200 minutes, With this process modification of a first chlorine dioxide step, an efficient destruction of undesired organic acids is obtained, while at the same time improved viscosity/strength of the pulp can be obtained of the finally bleached pulp with a whiteness of approximately 90% ISO. |
