Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station

GeoTreesearch - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

(596 KB bytes)

Title: Optimization of ECF bleaching of kraft pulp. Part 1, Optimal bleaching of hardwood pulps made with different alkali charges

Author: McDonough, Thomas J.; Uno, Shunichiro; Rudie, Alan W.; Courchene, Charles E.;

Date: 2008

Source: Tappi journal. (Jan. 2008): Pages 4-10

Publication Series: Miscellaneous Publication

Description: In an earlier modeling study, we showed that when a hardwood kraft pulp is bleached in the D0(EO)D1ED2 sequence with a D0 stage kappa factor of 0.20, the brightness of the pulp emerging from the D2 stage can be accurately predicted from the brightness of the pulp entering that stage. The entering brightness, in turn is a well-defined function of the ratio of the D1 stage CIO2 charge to the (EO) stage kappa number. In the present study, we use the results of pulping and bleaching experiments on southern U.S. red oak chips to extend the model to account for the effect of changing the D0 kappa factor and use it to assess the effect of digester alkali charge on pulp bleachability. We also show how this approach can be used to minimize the total CIO2 requirement for any desired final brightness and to optimize the allocation of CIO2 to the three D stages of the D(EO)DED sequence of the two D stages of the D(EO)D sequence. Among the conclusions resulting from application of the model are that the combination of high effective alkali and high D0 kappa factor gives pulp with a higher final brightness ceiling than any other combination, but that for brightness targets of 91 or lower, the combination of low effective alkali and low kappa factor is the most economical.

Keywords: Chemical reactions, mathematical models, sulphate pulping process, pulping, bleaching, red oak, chlorine dioxide, wood pulp, bleaching, chlorine dioxide, hardwoods, sulfate pulping, bleaching, red oak, pulping, brightness

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.



McDonough, Thomas J.; Uno, Shunichiro; Rudie, Alan W.; Courchene, Charles E. 2008. Optimization of ECF bleaching of kraft pulp. Part 1. Optimal bleaching of hardwood pulps made with different alkali charges. Tappi Journal. 5(1): 4-10.


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.