| 摘要 |
Scaling problems in, for instance, washing apparatus occur when using fully closed liquid flow patterns in the manufacture of bleached cellulose pulp. The present invention provides a solution to this problem, and relates to a method for minimizing calcium caused scaling problems when washing and/or increasing the consistency of cellulose pulp suspensions and in other cellulose pulp suspension processes where the pulp suspension is treated in at least two stages, including at least one bleaching stage, alternately in a neutral/acidic and alkaline environment, wherein washing liquid (suspension liquid) is passed counter-currently such that the treatment process will be essentially fully closed with respect to the washing liquid (suspension liquid) flow pattern, characterized in that the major part of the calcium present in and on cellulose pulp fibres incoming to the treatment process is prevented from being released in the suspension liquid, by adding a water soluble, oxalate-containing chemical to the suspension liquid downstream of the neutral/acidic treatment stage and/or to the pulp suspension immediately prior to or in the neutral/acidic treatment stage. |
