CHLORINE FREE PROCESS FOR BLEACHING LIGNOCELLULOSIC PULP

摘要

IP 2379 CHLORINE FREE PROCESS FOR BLEACHING LIGNOCELLULOSIC PULP A chlorine-free bleaching process for lignocellulosic pulp characterized by a series of bleaching stages comprising in sequence a peroxide bleaching stage, the per oxide being selected from the group consisting of alkaline hydrogen peroxide, acidic hydrogen peroxide, and peroxy acid and at least one ozone bleaching stage and in one embodiment the sequence including an initial oxygen bleaching stage before the peroxide bleaching stage. In continuous operation the effluent from each of these sequential stages provides the preferred wash for the preceding washing step and the diluent for the preceding bleaching stage, the final effluent being recyclable for effective closed cycle operation.