Process for bleaching pulps.

摘要

Bleaching of mechanical pulps to high degrees of brightness with the aid of H2O2 in alkaline medium in two successive stages separated by a washing, in which no use is made of sodium silicate or of a compound of the same effectiveness by using a quantity of hydrogen peroxide of between 0.5 % and 3 % in the first stage and a larger quantity of hydrogen peroxide of between 2 % and 5 % in the second stage.