1 ENHANCED PULP BLEACHING AT SAPPI FINE PAPER’S STANGER MILL USING PEROXYBOOST TM T.A.E.D ACTIVATED PEROXIDE Iain Kerr and Chris Baum Abstract The peroxide bleach activator T.A.E.D (Tetra Acetyl Ethylene Diamine) reacts with peroxide to form a strong oxidant, which has been found to enhance the performance of peroxide. The T.A.E.D granule has been given the trade name PeroxyBoost TM by Warwick International Group Limited UK can be used under both alkaline and near neutral conditions which demonstrates its flexibility in application. The combination of PeroxyBoost TM with peroxide (Pa) and a Q stage (QPa) under near neutral conditions (pH 6 - 8) offers a safe, low capital alternative for delignifying chemical pulps to using preformed peracids or other strong oxidising species. Research studies and now recent commercial experience has shown that the strong oxidant generated from the reaction between PeroxyBoost TM and peroxide under neutral pH provides significant delignification and brightness gain for various chemical pulps (Kraft, sulphite; hard, soft and non-woods) with good maintenance of viscosity. Alternatively, the use of PeroxyBoost TM within an alkaline P stage can enhance brightening of mechanical pulps. The combination of PeroxyBoost TM with peroxide under near neutral conditions can also be applied towards the end of bleaching sequences to give high brightness. Results from studies have shown that the use of PeroxyBoost TM combined with peroxide under near neutral conditions, followed by a conventional alkaline peroxide stage (i.e. Pa-P sequence) to bleach softwood and hardwood Kraft and hardwood sulphite pulps gives rise to higher brightness than two conventional peroxide stages (P-P sequence). Introduction As with most mature industries, there is a continual drive to identify more efficient and cost effective means of producing the final product. The pulp and paper industry is no exception to this and coupled with the ever present market and environmental demands, is in a continuous drive to improve productivity and quality combined with reducing overall working costs and environmental impact. Today’s paper makers are faced with matching a moving base sheet target brightness to compete with the mill’s external competitors. This in turn leads to increasing pressure on the pulp mill manager to increase final pulp brightness without increasing chlorine bleach chemical consumption. The local authorities in and around most mills are scrutinising the quantity and quality of the discarded effluent to ensure stringent adherence to their regulations. New environmental legislation will result in the introduction of a waste discharge charge and a charge for water use.