Other Ways to Use Ozone in a Bleaching Sequence, 1995 Pulping Conference Proceedings
Christine Chirat
Centre Technique du Papier
Dominique Lachenal
Ecole Française de Papeterie
ECF bleaching sequences of the D1 EOP D2 E D3 type (P in EOP and E between D2 and D3 being optional) for softwood and hardwood kraft pulps have been modified by total and partial replacement of chlorine dioxide by ozone in Dl and D2 to give Z EOP D2 E D3 , (D1 Z) EOP D2 E D3 and (D1 Z) EOP (D2 Z) E D3 . In these sequences lkg of ozone replaced up to 4 kg of chlorine dioxide depending on the conditions. AOX formation was decreased, and pulp viscosity was generally maintained. An ozone stage was also added at the end of TCF and ECF sequences to increase the final brightness. Ozone charges as low as 0.2% were found particularly efficient. Acidification was not needed before ozonation. Pulp viscosity and brightness stability were not affected.
Other Ways to Use Ozone in a Bleaching Sequence, 1995 Pulping Conference Proceedings