| 摘要 |
An improved bleaching process for bleaching pulp having at least one Eop stage or Ep stage which comprises subjecting the pulp to a Q stage in which the pulp is treated with a chelating agent at a pH of from greater than 2.5 to less than 7 followed by interstage washing prior to treating the pulp in the Eop or Ep stage. Q stage washing can be at any stage in the process prov ided that Q stage occurs prior to Eop or Ep stage. For example, Q stage wash ing may occur after brownstock washing at prior to any delignification stage . Q stage washing can also occur after earlier delignification stages or an oxygen delignification stage or a Do delignification stage. Q stage washing immediately preceding the Eop or Ep stage, or can be separated from these st ages by one or more other stage.
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