| 摘要 |
<p>The invention relates to a process for the bleaching of chemical pulp, process which comprises one or several oxidation steps and one or several alkali treatment steps and in which the pulp is treated with an enzyme. The essential idea of the invention is that the pulp is treated with an enzyme in two or more different steps of the process, an oxidation and/or alkali treatment being most preferably carried out between the enzyme treatment steps. The oxidizing chemical used is most preferably oxygen, although peroxide and/or chlorine and/or chlorine dioxide can also be used in addition to or instead of it, and in the enzyme treatment steps, which preferably number 2-4, the same enzyme or alternatively two or more different enzymes may be used. By the enzyme treatment according to the invention, the amount of toxic organic compounds inthe bleaching effluent is decreased and at the same time the chemical oxygen consumption of the effluent is decreased.</p> |
