Abstract

Various ways were explored to reduce Mn-induced peroxide decomposition under conditions similar to industrial bleaching of mechanical pulps. It was found that hydrogen peroxide is more stable if Mn (II) or (III) are stabilized prior to peroxide addition. Sodium silicate/magnesium sulfate solution stabilized hydrogen peroxide in the presence of both Mn(II) and Mn(III), while diethylenetriamine pentaacetic acid (DTPA) effectively stabilized alkaline peroxide in the presence of Mn(II), but not Mn(III).Magnesium hydroxide/sodium silicate solution was not effective in stabilizing both Mn (II) and (III); however, microwave assisted sodium silicate-Mn complex modification resulted in complete peroxide stabilization of both Mn (II) and (III).

Key words: Manganese, peroxide decomposition, bleaching, stabilizers, chelant.