| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing breached pulp by treatment in an alkali oxygen bleaching process and treatment in a multistage bleaching process, wherein high strength bleached pulp is obtained and use of bleaching agent required for bleaching the pulp to obtain desired whiteness is much decreased. SOLUTION: The method for producing bleached pulp comprises digesting a lignocellulose material to obtain unbleached pulp, treating the unbleached pulp in an alkali oxygen bleaching process and treating the pulp in a multistage bleaching process, wherein the alkali oxygen bleaching process is performed in a multistage continuing two or more reaction devices of a pump, a mixer and a reactor, at least the reactor in the second stage of the alkali oxygen bleaching process is an upflow type where the pulp slurry is pushed up from a lower part to an upper part, the pressure at the inlet of each reactor is 0.7-1.5 MPa, the difference between the minimum pressure and the maximum pressure is within 0.25 MPa in each reactor, and the treating temperature in each reactor is preferably 95-120°C. COPYRIGHT: (C)2005,JPO&NCIPI
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