| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for bleaching pulp, capable of performing a high efficiency chlorine dioxide bleaching and hexeneuronic acid removal simultaneously, reducing the using amount of the chemical in the later stage and also obtaining the pulp having a high whiteness and less discoloration, also provide a technology for improving an efficiency of an oxygen-based bleaching chemical in the later stage by dissolving for removing metals by an acid produced in the chlorine dioxide bleaching and suppressing the generation of a scale by dissolving for removing the metals. SOLUTION: This method for bleaching the pulp is provided by elevating temperature to 80-110°C in the chlorine dioxide bleaching stage and setting pH after the completion of the bleach as acidic, preferably pH=1-4 to perform the bleaching by the chlorine dioxide efficiently and at the same time, capable of performing the decomposition and removal of the hexeneuronic acid. Also, by washing the pulp treated with the chlorine dioxide, the efficiency of the oxygen-based bleaching chemical in the later stage can be improved, and further the generation of an organic acid metal scale in the bleaching process of later stage can be suppressed. COPYRIGHT: (C)2003,JPO
|
