Abstract: The present invention provdes an additive for reducing brightness loss upon pulp refining comprising in combination at least one anionic polymeric compound and at least one inorganic polymer, preferably such combinations wherein any of such anionic polymeric compounds are of low molecular weight. The preferred inorganic polyphosphates of such combination are those having average polymerization numbers of from about 10 to about 45. The weight proportion of inorganic polyphos-hate to anionic polymeric compound in such combination can be within the range of about 1:10::10:1.The present invention also provides pulp refining processes wherein such additive is added at a sufficient amount to the pulp material being refined to reduce brightness loss, such as at dosages of from about 0.0025 to about 0.5 weight percent additive actives to dry pulp, and end product pulps produced by such processes.

Abstract: A method for increasing the final brightness of pulp contaminated with iron or manganese in a chlorine bleaching process of the type comprising one or more alkaline stages which comprises treating the pulp with at least 0.1 lbs. per ton of a water-soluble chelating agent.