| 摘要 |
<p>A method for the bleaching of hardwood and softwood pulp without chlorine or chlorine derivatives that provides a pulp with high brightness, good physical strength, and a low degree of brightness reversion. Hardwood pulp can be bleached without chlorine or chlorine derivatives to a high brightness level using the specific sequence OXZP. Optionally, the pulp can be subjected to alkaline extraction or enhanced alkaline extraction steps between the treatment steps to assist the removal of the lignin, as necessary. Softwood pulp can be bleached without chlorine or chlorine derivatives to a high brightness level also using the specific, yet different, optimized, sequence of process steps OXEpZP or OXZ1EpZ2P. Softwood RDH (rapid displacement of heat) pulp is bleached with the sequence XEpZP.</p> |
