Chemical pulp

In the bleaching of kraft pulp, the internationally most important pulp type, hydrogen peroxide is one of the chemicals applied in multi-stage processes. Alkaline conditions are required to generate the active bleaching species from H₂O₂, the perhydroxyl anion. Consequently, extraction stages can be used for peroxide addition to boost the effects on extraction and brightness.

The application of H₂O₂ allows

• top brightness levels with improved brightness stability
• optimized economy through savings in the total chemicals required
• low residual of halogenated compounds, both in pulp (OX) and in effluent (AOX)
• low effluent color

Hydrogen peroxide is applied as the exclusive bleaching agent in sulfite pulp brightening. In single or two-stage processes it allows bleaching to full brightness.

Evonik's Applied Technology Center offers technical assistance to customers for the evaluation and the optimization of existing processes, as well as the evaluation of alternatives for the bleaching procedure. Information and assistance in setting up storage tanks and dosing units from our Engineering Services is available. Internationally presented papers on chemical pulp bleaching are available on a wide number of important technical topics.