| 摘要 |
The method involves an acid bleaching stage, an intermediate treatment after the acid bleaching stage during which at least one complex building is added, an extraction stage during which the pulp is treated with hydrogen peroxide in conjunction with which magnesium ions are added to the pulp. The pulp is not washed between the acid bleaching stage and the addition of complex builders and magnesium ions. The pulp is bleached with ozone before the complex builders and magnesium ions are added. The pulp is pretreated with acid to give a final pH between 2 and 4 before ozone treatment. The pulp is pretreated with complex builders before ozone treatment, which is followed by further treatment with complex builders and addition of magnesium ions before hydrogen peroxide treatment. |
