The main objective of bleaching is to produce a brighter pulp. This is accomplished in chemical pulps primarily through lignin removal. The removal of other compounds is another objective of the bleaching process. These compounds include resins, fatty acids and other extractives.
The Pulp and Paper Process Development Center has worked closely with the pulp and paper industry to develop new and effective bleaching sequences. We can perform a wide range of bleaching sequences on mechanical, recycle and chemical pulps. Both Totally Chlorine Free (TCF) and Elemental Chlorine Free (ECF) sequences are routinely performed. The sequences may be comprised of a variety of stages, including chelation, enzyme, oxygen, ozone, chlorine, chlorine dioxide, extraction and hydrogen peroxide stages. Oxygen delignification and hydrogen peroxide bleaching at high temperature and high pressure are carried out in reactor vessels. Ozonation at high consistency takes place in a rotating glass vessel. For liquid bleaching agents, the more conventional technique involving polyester bags is used.
Bleach Effluent Analysis
To begin working with us, please visit our Planning Your Project page.
To find out more about our organization and how to work with us, please refer back to our Home page. To learn more about stock preparation and refining at the PDC, please continue on to the next page.
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