| 摘要 |
PROBLEM TO BE SOLVED: To raise the whiteness level of mechanical pulp by bleaching it with hydrogen peroxide. SOLUTION: A method for producing bleached mechanical pulp, which involves using a pulping mill incorporated with a primary refiner and a secondary refiner, comprises the 1st step of feeding a cellulosic material (e.g. wood chips) and refining it into pulp, wherein the wood chips have an initial whiteness level, the 2nd step of feeding the refining system of the pulping mill with a bleaching liquid, wherein the bleaching liquid includes a certain amount of an alkali including >0 wt.% but <=100 wt.% of magnesium hydroxide, soda ash or a combination thereof and a certain amount of hydrogen peroxide, and the 3rd step of holding the pulp together with the bleaching liquid at about 85 deg.C to about 160 deg.C for about 2 to about 180 min.
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