Use of Zeolites for the Bleaching of Mechanical Pulp, 2001 Pulping Conference Proceedings

C. Leduc, S. Rouaix, C. Daneault--The use of zeolites for inhibition of transition metal catalysed decomposition of hydrogen peroxide was evaluated. Zeolites with different compositions of aluminum and silicon were tested in pretreatment experiments using commercial mechanical pulp. This ratio aluminum-silicon of zeolites have an impact on the efficiency of the chelating process of manganese ions. The effect of the pH pretreatment reaction was investigated. The hydrogen peroxide bleaching of these pretreated pulps with zeolites was evaluated in terms of ISO brightness, color coordinate b* and residual peroxide. These results were compared to a conventional chelating agent DTPA used by the industry. Zeolites allow similar brightness gains compared to those obtained with DTPA. Zeolites represents an interesting alternative to DTPA for the industry considering the fact that we use an inorganic compound and that could result in a reduction of the total charge regarding the environment.