| 摘要 |
<p>A method for bleaching sulphate pulp to an ISO brightness of at least 85 via the kraft process and using an acidic peroxide bleaching step (Pa) comprises the use of ozone and/or chlorine dioxide as bleaching chemicals during the peroxide bleaching step. - Preferably between the kraft cooking and (Pa) steps the pulp is treated with acid, EDTA, DTPA and/or enzyme to remove heavy metals, and with acid and/or peroxide to remove lignin.</p> |
