Peroxide bleaching process for pref. chemical pulp

摘要

In the process for bleaching cellulosic pulp with peroxide, using at least one pressurised bleaching vessel: (a) peroxide is blended with the pulp to form an intimate mixt.; (b) the mixt. is added to the pressurised bleaching vessel where the pulp is bleached in a superatmospheric pressure to form oxygen and reaction gases; (c) at least 20 % of the oxygen and reaction gases are removed from the mixt. before all the peroxide is used up; (d) the mixt. is added to a second vessel where the temp. is greater, pressure is lower and treatment time is longer than in the first vessel; and (e) the remaining oxygen and reaction gases are removed from the pulp.