Use of oxygen in the delignification and bleaching of pulps

摘要

There has been a growing trend worldwide in recent years to use elemental chlorine free(ECF)and totally chlorine free(TCF)pulp bleaching processes,so much so that the annual output of pulp bleached in this way has risen from 5 to nearly 90 million tonnes.In parallel,the annual output of traditionally bleached pulp has fallen from 70 to less than 20 million tonnes(1).