| 摘要 |
A process for the removal of transition metal ions from wood fiber slurries (cellulose pulp, including mechanical and chemical pulps), such as manganese, applies a pulse of solution containing beneficial metal ions, such as magnesium, chelant, or ion exchange chemical (or acid at a pH between about 1-4) through a pulp mat or pad. This leads to an efficient removal of manganese and a good retention of magnesium in pulp fibers at a magnesium sulfate charge as low as about 1 % (on pulp). Results from subsequent peroxide bleaching show that the MgSO4 eluted pulp has a similar bleaching performance as that of the conventional DTPA chelated pulp. More efficient removal of manganese from pulp fibers can be achieved when DTPA chelation is performed by applying a pulse of DTPA solution through a pulp pad or mat compared to that of a conventional chelation stage. |
