Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Alan W. Rudie; Peter W. Hart
    Date: 2006
    Source: 2006 Engineering, Pulping, and Environmental Conference, Nov. 5-8, 2006, Atlanta, GA. Atlanta, GA : TAPPI, 2006: [10] pages.
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (218 KB)


    The majority of the barium present in the pulping process exits the digester as barium carbonate. Barium carbonate dissolves in the bleach plant when the pH drops below 7 and, if barium and sulfate concentrations are too high, begins to precipitate as barium sulfate. Barium is difficult to control because a mill cannot avoid this carbonate-to-sulfate transition using common bleaching technology. An advantage in controlling barium scales is that the sulfate, once formed, will not redissolve to any appreciable extent, and this reduces the rate at which barite scale can form in other locations in the bleach plant. A mill has relatively few options for controlling barium sulfate scale. The first is to ensure very good debarking to minimize barium entering the mill with the wood. The second option is to minimize sulfate content of the first chlorine dioxide stage in the bleach plant. Sulfate is minimized through good brown stock washing and by using sulfuric acid for pH control instead of chlorine dioxide generator spent acid. Sulfate can also be reduced by operating the initial chlorine dioxide stage at higher pH, but this will work only in mills where calcium scales are not a concern. A third option is to use crystal modifiers (scale inhibitors). Scale inhibitors can be an expensive solution but are effective at delaying precipitation, and if the location can be moved from pumps and process piping into a tower, the impact of the scale is reduced. Because barium sulfate will not redissolve in the bleach plant, a barite deposit is less likely to reoccur somewhere else in the bleach plant.

    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.


    Rudie, Alan W.; Hart, Peter W. 2006. Modeling and minimization of barium sulfate scale. 2006 Engineering, Pulping, and Environmental Conference, Nov. 5-8, 2006, Atlanta, GA. Atlanta, GA : TAPPI, 2006: [10] pages.


    Barium carbonate, chlorine dioxide, bleaching, barium sulphate, water quality management, barium, water pollution, pulping, wood-pulp, bleaching, pulp mills, incrustations, scale, digesters, pulp and paper processes, trace metals

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page