Additive composition for reducing anthraquinone requirements in pulping of lignocellulosic material

Abstract

An improved process for delignification of lignocellulosic raw material, such as wood chips, for the production of cellulose pulps for use in the manufacture of paper or paperboard and an improved pulping aid composition for use in said process are disclosed wherein the wood chips are treated in a closed reaction vessel with an alkaline pulping liquor with an amount of a cyclic keto compound, such as anthraquinone, included therein for achievement of a determined pulp yield, wherein the improvement comprises a reduction in the amount of anthraquinone required to achieve said yield by the addition to said alkaline pulping liquor, in addition to a reduced amount of the anthraquinone, a surfactant mixture comprising at least one alkyl alcohol alkoxylate and at least one polyoxyalkylene glycol ether of an ester of an acid selected from the group consisting of ricinoleic acid and 12-hydroxystearic acid.

Dependencies are inferred from the claim text.