Title: Method of increasing cellulosic pulp yields in an alkaline digestion process

Abstract: Increased pulp yields are obtained by alkaline digestion of cellulosic material until a pulp yield of not above 65% is obtained, lowering the pH of the digestion liquid is lowered to allow 11 causing organic substances to precipitate from the digestion liquor and then continuing digestion in the presence of the pulp until at least 5% of the organic substances which have been precipitated out are absorbed by the pulp.

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Inventors: Backstrom, Inga L. (Stockholm, SW)
Hartler, Nils J. C. (Lidingo, SW)
Kringstad, Knut P. (Vallingby, SW)

Application Number: 415153
Filing Date: 1973-11-12
Publication_date: 1976-02-10
Assignee: Svenska Traforskningsinstitutet (Stockholm, SW)
Primary Class(es): 162/16 162/61, 530/500
Other Classes:
US Patent Ref:

1859888	May, 1932	Richter	162/16.
2167556	Jul, 1939	Smull	162/16.
2686120	Aug, 1954	Marshall et al.	162/16.
2976273	Mar, 1961	Ball et al.	162/16.
3428520	Feb, 1969	Yiannos	162/16.
3806403	Apr, 1974	Ferguson	162/16.

Other Refs: 130,377

Jul, 1947	AU

Primary Examiner: Lindsay, Jr., Robert L.
Assistant Examiner: Corbin, Arthur L.
Attorney: Oldham & Oldham Co.