Replacement of elemental chlorine-free (ECF) with the traditional method for bagasse soda pulp bleaching

The aim of this study was to solve the environmental problems caused after the bleaching of bagasse pulp by hypochlorite sodium in Pars paper mill. For this purpose, ECF bleaching method was used by performing OQPDEP sequence. The properties of bleached paper were compared to the bagasse unbleached paper as control and some paper properties that made from bagasse bleached pulp by EH sequence in Pars paper mill. The results showed that increasing the bleaching time of bagasse pulp from 30 to 120 minutes by oxygen had no significant effect on paper brightness, but paper density, burst and tear indices decreased. Pulp bleaching by O1QP3D(EP) sequence compared to bagasse unbleached paper led to the paper brightness of about 75% ISO that is about 5% ISO more than the Pars commercial bleached paper. Paper strengths were similar to Pars commercial paper made of soda bagasse and the national standard of Iran (ISIRI 4120). Soda pulp bleaching using O1QP3D(EP) sequence has led to acceptable physical, optical and mechanical properties in addition to environmental benefits such as reduce pollution. So, it is recommended to replace the current bleaching method of Pars paper mill by the mentioned sequence.